HSC Physics Sample Exams

2001 H I G H E R S C H O O L C E R T I F I C AT E E X A M I N AT I O N

Physics

Total marks – 100 General Instructions • Reading time – 5 minutes • Working time – 3 hours • Write using black or blue pen • Draw diagrams using pencil • Board-approved calculators may be used • A data sheet, formulae sheets and Periodic Table are provided at the back of this paper • Write your Centre Number and Student Number at the top of pages 13, 15, 17 and 21

Section I

Pages 2–23

75 marks This section has two parts, Part A and Part B Part A – 15 marks • Attempt Questions 1–15 • Allow about 30 minutes for this part Part B – 60 marks • Attempt Questions 16–26 • Allow about 1 hour and 45 minutes for this part Section II

Pages 25–31

25 marks • Attempt ONE question from Questions 27–31 • Allow about 45 minutes for this section 433

Section I 75 marks Part A – 15 marks Attempt Questions 1–15 Allow about 30 minutes for this part

Use the multiple-choice answer sheet. Select the alternative A, B, C or D that best answers the question. Fill in the response oval completely. Sample:

2+4=

(A) 2 A

(B) 6

(C) 8

B

C

(D) 9 D

If you think you have made a mistake, put a cross through the incorrect answer and fill in the new answer. A

B

C

D

If you change your mind and have crossed out what you consider to be the correct answer, then indicate the correct answer by writing the word correct and drawing an arrow as follows.

correct A

B

C

–2–

D

1

A person has a mass of 70.0 kg. What is the weight of the person at the Earth’s surface? (A) 70.0 kg (B)

70.0 N

(C)

686 kg

(D) 686 N

2

At a particular moment, a positively charged particle is moving with velocity v in a magnetic field as shown.

Magnetic field out of page

v

At this moment, what is the direction of the force on the positively charged particle? (A) To the right (B)

To the left

(C)

Into the page

(D) Out of the page

–3–

3

The resistance of mercury at various temperatures is shown in the graph.

Resistance (Ω)

0.16

0.08

0.00 0

2

4 6 Temperature (K)

8

Between which two temperatures does mercury always act as a superconductor? (A) 0 K and 4.2 K (B)

4.2 K and 4.5 K

(C)

4.5 K and 8.0 K

(D) 0 K and 8.0 K

4

Two types of generator are shown.

N

N S

S

Resistance Resistance Generator 2

Generator 1

What type of current is produced by each generator when connected to an external resistance? (A) Both produce d.c. (B)

Both produce a.c.

(C)

Generator 1 produces d.c. and Generator 2 produces a.c.

(D) Generator 1 produces a.c. and Generator 2 produces d.c. –4–

The graph shows the forces experienced by an astronaut during a rocket launch into a stable orbit.

Forces on astronaut

5

S

T

U

V

W

Time In which time interval was the acceleration of the rocket the greatest? (A) S–T (B)

T–U

(C)

U– V

(D) V–W

6

The signal from a microwave transmitter can be thought of as a beam of photons. The photons from a particular transmitter have a wavelength of 3.5 × 10–2 m. What is the approximate energy of each photon? (A) 7.73 × 10–44 J (B)

5.68 × 10–24 J

(C)

2.32 × 10–35 J

(D) 1.89 × 10–32 J

–5–

7

An astronaut is standing on Mars. The astronaut throws an object of mass 0.30 kg vertically upward at an initial speed of 9.0 m s–1. It reaches a maximum height of 11 metres. What is the magnitude of the acceleration of the object? (A) 1.4 m s–2 (B)

3.7 m s–2

(C)

9.0 m s–2

(D) 9.8 m s–2

8

A light rod has a coil of insulated copper wire fixed at one end and is pivoted at the other end. The result is a pendulum which is free to swing back and forth. A magnet is placed underneath this pendulum. The arrangement is shown in the diagram. Pivot

Rod

Coil

Magnet

The pendulum is pulled back and then allowed to swing. Which of the following would cause the pendulum to come to rest most quickly? (A) Replacing the magnet with a stronger one (B)

Shortening the pendulum

(C)

Replacing the rod with a heavier one

(D) Connecting the ends of the coil by a piece of copper wire

–6–

9

Which is the most suitable means of reliable and continuous communication between an orbiting satellite and Earth? (A) Light from a green laser (B)

Microwaves

(C)

Radio waves

(D) Sound waves

10

An electric motor is connected to a power supply of constant voltage. The motor is allowed to run at different speeds by adjusting a brake. Which graph best shows how the current through the motor varies with speed? (B)

0

Current

Current

(A)

0

Speed

0

11

Current

(D) Current

(C)

Speed

0

Speed

Speed

A transformer has a primary coil with 60 turns and a secondary coil with 2300 turns. If the primary voltage to the transformer is 110 V, what is the secondary voltage? (A) 2.4 × 10–4 V (B)

2.4 × 102 V

(C)

1.3 × 103 V

(D) 4.2 × 103 V

–7–

12

Which of the following statements best describes the reason why some materials become superconducting at very low temperatures? (A) The ions in the superconductor form a regular crystal lattice. There are long channels through the lattice along which the electrons can pass without colliding with the lattice. (B)

Vibrations of the crystal lattice are so small that they do not interfere with the motion of the electrons.

(C)

Electrons in a superconductor have very low energy. Their energy is so low that they cannot transfer energy to the crystal lattice in a collision.

(D) Electrons ‘pair up’. These electron pairs pass through the crystal lattice of the superconductor without losing energy in collisions with the lattice.

13

A rocket car moves on a straight horizontal track. Half of the initial mass of the rocket car is propellant. During the run, propellant is consumed at a constant rate and ejected at a constant nozzle velocity. Which of the following best describes the force propelling the rocket car, and the magnitude of the acceleration of the rocket car while the propellant is being ejected? Force

Acceleration

(A)

constant

constant

(B)

increasing

constant

(C)

constant

increasing

(D)

increasing

increasing

–8–

14

Two straight metal rods, P and Q, have the same length. They are each pivoted at one end and rotated with the same angular velocity so that they sweep out horizontal circular paths as shown in diagrams X and Y. A constant current I is flowing along each rod, as shown. In diagram X, a constant magnetic field is applied at right angles to the plane of the circular path. In diagram Y, a uniform magnetic field of the same magnitude is applied in the plane of the circular path.

I

I P

Diagram X

Q

Diagram Y

Which of the following statements about the forces acting on rod P and rod Q is correct? (A) The magnitude of the force on P is exactly the same as the magnitude of the force on Q at all times. (B)

The magnitude of the force on P is constant and the magnitude of the force on Q is zero.

(C)

The magnitude of the force on P is constant and the magnitude of the force on Q varies with time.

(D) The magnitude of the force on P varies with time and the magnitude of the force on Q is constant.

–9–

A student releases a ball from eye level. The ball bounces several times. Which velocity vs time graph best represents the ball’s motion?

Velocity

Time

Velocity

Time

Velocity

(A)

Time

Velocity

15

Time

(B)

(C)

(D)

– 10 –

2001 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I (continued) Part B – 60 marks Attempt Questions 16–26 Allow about 1 hour and 45 minutes for this part

Student Number

Answer the questions in the spaces provided. Show all relevant working in questions involving calculations.

Marks Question 16 (4 marks) Muons are very short-lived particles that are created when energetic protons collide with each other. A beam of muons can be produced by very-high-energy particle accelerators. The high-speed muons produced for an experiment by the Fermilab accelerator are measured to have a lifetime of 5.0 microseconds. When these muons are brought to rest, their lifetime is measured to be 2.2 microseconds. (a)

Name the effect demonstrated by these observations of the lifetimes of the muons.

1

............................................................................................................................... (b)

Calculate the velocity of the muons as they leave the accelerator. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

434

– 13 –

3

Marks Question 17 (6 marks) A rocket was launched vertically to probe the upper atmosphere. The vertical velocity of the rocket as a function of time is shown in the graph. 5.0

Velocity (km s–1)

4.0 3.0 2.0 1.0 0

(a)

0

40

80 120 160 200 Time after lift-off (s)

240

Using either words or calculations, compare the acceleration of the rocket at t = 20 s with its acceleration at t = 100 s.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Account for the shape of the graph over the range of time shown. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... – 14 – © Board of Studies NSW 2001

4

2001 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 18 (6 marks) A 30 kg object, A, was fired from a cannon in projectile motion. When the projectile was at its maximum height of 25 m, its speed was 20 m s –1. An identical object, B, was attached to a mechanical arm and moved at a constant speed of 20 m s–1 in a vertical half-circle. The length of the arm was 25 m. A

B

20 m s –1

25 m

20 m s –1

25 m

Ground

Ground Pivot

Ignore air resistance. (a)

Calculate the force acting on object A at its maximum height.

1

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Calculate the time it would take object A to reach the ground from its position of maximum height.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (c)

Describe and compare the vertical forces acting on objects A and B at their maximum heights. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

435

– 15 –

3

Marks Question 19 (4 marks) How does Einstein’s Theory of Special Relativity explain the result of the Michelson–Morley experiment?

4

......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

Question 20 (4 marks) The electrical supply network uses a.c. and a variety of transformers between the generating stations and the final consumer. Explain why transformers are used at various points in the network. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 16 – © Board of Studies NSW 2001

4

2001 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 21 (3 marks) A fan that ventilates an underground mine is run by a very large d.c. electric motor. This motor is connected in series with a variable resistor to protect the windings in the coil. When the motor is starting up, the variable resistor is adjusted to have a large resistance. The resistance is then lowered slowly as the motor increases to its operating speed. Explain why no resistance is required when the motor is running at high speed, but a substantial resistance is needed when the motor is starting up. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

436

– 17 –

3

Marks Question 22 (7 marks) Two parallel wires are separated by a distance of 0.75 m. Wire X is 3.0 m long and carries a current of 2.0 A. Wire Y can be considered to be infinitely long and carries a current of 5.0 A. Both currents flow in the same direction along the wires. 3.0 m Wire X 2.0 A 0.75 m Wire Y 5.0 A (a)

What is the direction of the force that exists between the two wires?

1

............................................................................................................................... On the axes, sketch a graph that shows how the force between the two wires would vary if the length of Wire X was increased.

2

Force

(b)

Length of Wire X (c)

In your Physics course you have performed a first-hand investigation to demonstrate the motor effect. Explain how your results demonstrated that effect. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... – 18 –

4

Marks Question 23 (6 marks) Discuss the effects of the development of electrical generators on society and the environment. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 19 –

6

2001 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 24 (6 marks) Sir William Bragg and his son Sir Lawrence Bragg shared the Nobel prize for physics in 1915 for their work on X-ray diffraction and crystal structure analysis. (a)

Describe ONE way in which an understanding of crystal structure has impacted on science.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Outline the methods of X-ray diffraction used by the Braggs to determine the structure of crystals. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

437

– 21 –

4

Marks Question 25 (6 marks) A student carried out an experiment on the photoelectric effect. The frequency of the incident radiation and the energy of the photoelectrons were both determined from measurements taken during the experiment. The results obtained are shown in the table:

(a)

Frequency of incident radiation (× 1014 Hz)

Energy of photoelectrons (× 10 –19 J)

6.9

1.22

8.2

1.70

9.1

3.70

9.9

3.05

10.6

3.38

11.8

3.91

Graph these results on the grid, including the line of best fit.

Question 25 continues on page 23 – 22 –

4

Marks Question 25 (continued) (b)

How could the reliability of the experiment be improved?

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

Question 26 (8 marks) In the context of semiconductors, explain the concept of electrons and holes. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 23 –

8

2001 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics Section II 25 marks Attempt ONE question from Questions 27–31 Allow about 45 minutes for this section Answer the question in a writing booklet. Extra writing booklets are available. Show all relevant working in questions involving calculations.

Pages

438

Question 27

Geophysics ..................................................................... 26

Question 28

Medical Physics ............................................................. 27

Question 29

Astrophysics ............................................................. 28–29

Question 30

From Quanta to Quarks .................................................. 30

Question 31

The Age of Silicon ......................................................... 31

– 25 –

Marks Question 27 — Geophysics (25 marks) (a)

(b)

(i)

Name the instrument used in local gravity surveys.

1

(ii)

Describe how that instrument is used in resource exploration.

2

The diagram shows a map of the part of an ocean that includes two chains of features, a chain of islands and a chain of seamounts.

Continent

Chain

63

ounts

of seam

Ocean

56 54 47 43

N

28 22

Chai

n of

12 7 54 2

islan

ds

0

Age (Ma)

(i)

Name the geophysical phenomenon that accounts for the shape of the chain of islands.

1

(ii)

Account for the formation and alignment of the chain of islands and the chain of seamounts.

3

(c)

Describe how you carried out a first-hand investigation to determine the relationship between the nature of a surface and the radiation reflected from it.

4

(d)

When the theory of plate tectonics was first proposed, some parts of the scientific community were reluctant to accept it.

6

Discuss the theory of plate tectonics and the evidence leading to its acceptance.

(e)

Discuss how information gathered from seismic observations has led to greater understanding of the structure of the Earth.

– 26 –

8

Marks Question 28 — Medical Physics (25 marks) (a)

(b)

(i)

Identify the purpose of a coherent bundle of optical fibres in an endoscope.

1

(ii)

An optical fibre consists of a central core surrounded by cladding. Describe the role of the core and cladding.

2

The table shows information relating to the transmission of sound through some types of body tissue. Tissue

Acoustic impedance (× 106 kg m–2 s–1)

Density (kg m–3)

Velocity of sound (m s–1)

Muscle

1.70

1040

1630

Fat

1.38

945

1460

Bone

7.80

2560

3050

(i)

Identify ONE property of ultrasound.

1

(ii)

Justify why, in an ultrasound scan, a boundary between muscle and bone would show up more clearly than would a boundary between muscle and fat.

3

(c)

You have conducted a first-hand investigation to demonstrate the Doppler effect. Describe your investigation and conclusions.

4

(d)

‘CAT scans provide more information than X-rays, so they should be used whenever possible.’ Discuss this statement.

6

(e)

Explain why MRI can be used to detect cancerous tissues.

8

– 27 –

Marks Question 29 — Astrophysics (25 marks) (a)

(b)

(i)

Define the term binary stars.

1

(ii)

Describe the characteristics of its spectrum that identify a spectroscopic binary.

2

The table shows information about three stars in the Milky Way galaxy. Name

Spectral class

Distance from Sun (parsecs)

Apparent magnitude

Betelgeuse

M2

184

+0.41

Achernar

B5

20

+0.47

Deneb

A2

429

+1.24

(i)

Identify which of the stars has the greatest surface temperature.

1

(ii)

If Deneb and Betelgeuse were viewed from the same distance, which would appear brighter? Justify your answer.

3

Question 29 continues on page 29

– 28 –

Marks Question 29 (continued) (c)

A student carried out an experiment to examine the spectra of various light sources through spectroscopes as shown in the diagram. The student observed three different spectra.

4

Full range of colours

X Incandescent lamp

Spectroscope

Two yellow lines on a dark background

Y Sodium vapour lamp

Spectroscope

Range of colours with two black lines

Z Incandescent lamp

Sodium vapour

Spectroscope

Account for the differences in the three observed spectra. (d)

A new generation of Earth-based optical telescopes is advancing optical astronomy. Describe the advances in design that have been incorporated in large telescopes over recent years.

6

(e)

Explain how the data presented in Hertzsprung–Russell diagrams may be used to understand the evolution of stars.

8

End of Question 29 – 29 –

Marks Question 30 — From Quanta to Quarks (25 marks) (a)

(b)

(i)

Define nucleon.

1

(ii)

Contrast ONE property of nucleons.

2

The table shows the quantum numbers of the four lowest states of the hydrogen atom, together with the energies of those states. Quantum number, n

Energy (joule)

1 (Ground state)

0

2

1.63 × 10 –18

3

1.94 × 10 –18

4

2.04 × 10 –18

(i)

What is the energy of the photon emitted when an electron in the n = 4 level makes a transition to the n = 3 level?

1

(ii)

Use the data to draw the energy level diagram for hydrogen, and indicate on this diagram where the energy levels lie for quantum numbers greater than 4.

3

(c)

Describe how you carried out a first-hand investigation to determine the penetrating power of alpha, beta and gamma radiation on a range of materials.

4

(d)

The Manhattan Project is the codename given to the development of atomic (nuclear fission) bombs during World War II.

6

Discuss the significance of this project for society.

(e)

Analyse how Chadwick’s and Fermi’s work resulted in a greater understanding of the atom.

– 30 –

8

Marks Question 31 — The Age of Silicon (25 marks) (i)

State the name of the transducer that is commonly used in a light meter of a camera.

1

(ii)

Describe the relationship between the amount of light incident on the transducer referred to in part (i), and its resistance.

2

(a)

(b)

An ideal differential-input operational amplifier is connected into the following circuit. 500 kΩ 25 kΩ Vin = + 0.4 V

– Op. amp. Vout

+

(c)

(i)

Explain the function of the 500 kΩ resistor in this circuit.

1

(ii)

Determine the output voltage, Vout.

3

A student constructed the following circuit in which four different logic gates were used. The circuit had two inputs, A and B, and one output, S.

B

Key

Gate 1

A

P Gate 2 Q

4

Gate Function Gate 4

R

S

Gate 3

1 2 3 4

NAND NOT NOR OR

For each of the possible input states of A and B, construct a truth table showing the output of Gate 1 at P, Gate 2 at Q, Gate 3 at R and Gate 4 at S. (d)

Discuss the possibility that there may be a limit on the growth of computer power.

6

(e)

Discuss the impact that developments in electronics have had on society.

8

End of paper – 31 –

2001 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics DATA SHEET Charge on the electron, qe

–1.602 × 10–19 C

Mass of electron, me

9.109 × 10–31 kg

Mass of neutron, mn

1.675 × 10–27 kg

Mass of proton, mp

1.673 × 10–27 kg

Speed of sound in air

340 m s–1

Earth’s gravitational acceleration, g

9.8 m s–2

Speed of light, c

3.00 × 108 m s–1

µ Magnetic force constant,  k ≡ 0  2π  

2.0 × 10–7 N A–2

Universal gravitational constant, G

6.67 × 10–11 N m2 kg–2

Mass of Earth

6.0 × 1024 kg

Planck’s constant, h

6.626 × 10–34 J s

Rydberg’s constant, RH

1.097 × 107 m–1

Atomic mass unit, u

1.661 × 10–27 kg 931.5 MeV/ c 2

1 eV

1.602 × 10–19 J

Density of water, ρ

1.00 × 103 kg m–3

Specific heat capacity of water

4.18 × 103 J kg–1 K–1

– 33 –

FORMULAE SHEET c = fλ Intensity

Gm1 m2

F=−

∝

r2

1 d2

r3 T2

v1 sin i = v2 sin r

GM

=

4π 2

m1 + m2 = E=

R=

F q

4π 2 r 3 GT 2

d M = m − 5 log   10

V I

IA

P = VI

= 100

IB

(mB − mA )

Energy = VIt d= vav =

∆s ∆t

aav =

∆v v − u = ∆t t

F = BIl sin θ

Σ F = ma

F l

Ek =

1 p

1 2 mv 2

=k

I1 I2 d

τ = Fd

p = mv

τ = nBIA cosθ

∆ p = Ft

Vp Vs

– 34 –

=

np ns

5

FORMULAE SHEET Ep = −

F = qvB sin θ

Gm1 m2 r

E =

v = u + at

E = hf

v x 2 = ux 2 v y 2 = uy 2 + 2 ay ∆ y

Z = ρv

∆ x = ux t

Ir Io

1 2

∆ y = uy t + ay t 2 s u+v = t 2

2 Z2 − Z1 ] [ = [ Z2 + Z1 ] 2

 1 1 1 = RH  2 − 2  λ  n f ni 

lv = lo 1 −

tv =

V d

v2 c2

λ =

h mv

to 1−

v2 c2

Amplifier gain =

Ao =

– 35 –

Vo V+ − V−

Vout Vin

– 36 –

Yttrium

57–71

Strontium

56 Ba 137.3

Barium

88 Ra [226.0]

Radium

Rubidium

55 Cs 132.9

Caesium

87 Fr [223.0]

Francium

Rutherfordium

104 Rf [261.1]

Hafnium

72 Hf 178.5

Zirconium

90 Th 232.0

Thorium

Actinides 89 Ac [227.0]

Actinium

Protactinium

91 Pa 231.0

Praseodymium

59 Pr 140.9

Dubnium

105 Db [262.1]

Tantalum

73 Ta 180.9

Niobium

41 Nb 92.91

Vanadium

Uranium

92 U 238.0

Neodymium

60 Nd 144.2

Seaborgium

106 Sg [263.1]

Tungsten

74 W 183.8

Molybdenum

42 Mo 95.94

Chromium

Neptunium

93 Np [237.0]

Promethium

61 Pm [146.9]

Bohrium

107 Bh [264.1]

Rhenium

75 Re 186.2

Technetium

43 Tc [98.91]

Manganese

Plutonium

94 Pu [239.1]

Samarium

Americium

95 Am [241.1]

Europium

Curium

96 Cm [244.1]

Gadolinium

64 Gd 157.3

Ununnilium

Meitnerium

Hassium

63 Eu 152.0

110 Uun —

109 Mt [268]

62 Sm 150.4

Platinum

Iridium

78 Pt 195.1

Palladium

46 Pd 106.4

Nickel

108 Hs [265.1]

77 Ir 192.2

Rhodium

45 Rh 102.9

Cobalt

28 Ni 58.69

Osmium

76 Os 190.2

Ruthenium

44 Ru 101.1

Iron

27 Co 58.93

Berkelium

97 Bk [249.1]

Terbium

65 Tb 158.9

Unununium

111 Uuu —

Gold

79 Au 197.0

Silver

47 Ag 107.9

Copper

Californium

98 Cf [252.1]

Dysprosium

66 Dy 162.5

Ununbium

112 Uub —

Mercury

80 Hg 200.6

Cadmium

48 Cd 112.4

Zinc

30 Zn 65.39

Einsteinium

99 Es [252.1]

Holmium

67 Ho 164.9

113

Thallium

81 Tl 204.4

Indium

49 In 114.8

Gallium

31 Ga 69.72

Fermium

100 Fm [257.1]

Erbium

68 Er 167.3

Ununquadium

114 Uuq —

Lead

82 Pb 207.2

Tin

50 Sn 118.7

Germanium

32 Ge 72.61

Silicon

14 Si 28.09

Carbon

6 C 12.01

Sulfur

Phosphorus

Mendelevium

101 Md [258.1]

Thulium

69 Tm 168.9

115

Bismuth

83 Bi 209.0

Antimony

51 Sb 121.8

Arsenic

Nobelium

102 No [259.1]

Ytterbium

70 Yb 173.0

Ununhexium

116 Uuh —

Polonium

84 Po [210.0]

Tellurium

52 Te 127.6

Selenium

34 Se 78.96

16 S 32.07

15 P 30.97 33 As 74.92

Fluorine

Oxygen

Nitrogen

Lawrencium

103 Lr [262.1]

Lutetium

71 Lu 175.0

117

Astatine

85 At [210.0]

Iodine

53 I 126.9

Bromine

35 Br 79.90

Chlorine

17 Cl 35.45

9 F 19.00

8 O 16.00

7 N 14.01

Where the atomic weight is not known, the relative atomic mass of the most common radioactive isotope is shown in brackets. The atomic weights of Np and Tc are given for the isotopes 237Np and 99Tc.

Cerium

Lanthanum

Lanthanides 57 58 La Ce 138.9 140.1

Actinides

89–103

Lanthanides

39 Y 88.91

38 Sr 87.62

40 Zr 91.22

Titanium

Scandium

Calcium

26 Fe 55.85

29 Cu 63.55

37 Rb 85.47

25 Mn 54.94

Potassium

24 Cr 52.00

Aluminium

23 V 50.94

20 Ca 40.08

19 K 39.10

22 Ti 47.87

Magnesium

Sodium

21 Sc 44.96

13 Al 26.98

Boron

12 Mg 24.31

Name of element

11 Na 22.99

Atomic Weight Gold

Beryllium

Lithium

Symbol of element

5 B 10.81

79 Au 197.0

4 Be 9.012

3 Li 6.941 Atomic Number

KEY

PERIODIC TABLE OF THE ELEMENTS

Hydrogen

1 H 1.008

Ununoctium

118 Uuo —

Radon

86 Rn [222.0]

Xenon

54 Xe 131.3

Krypton

36 Kr 83.80

Argon

18 Ar 39.95

Neon

10 Ne 20.18

Helium

2 He 4.003

2002 H I G H E R S C H O O L C E R T I F I C AT E E X A M I N AT I O N

Physics

Total marks – 100 General Instructions • Reading time – 5 minutes • Working time – 3 hours • Write using black or blue pen • Draw diagrams using pencil • Board-approved calculators may be used • A data sheet, formulae sheets and Periodic Table are provided at the back of this paper • Write your Centre Number and Student Number at the top of pages 13, 17, 21 and 23

Section I

Pages 2–25

75 marks This section has two parts, Part A and Part B Part A – 15 marks • Attempt Questions 1–15 • Allow about 30 minutes for this part Part B – 60 marks • Attempt Questions 16–27 • Allow about 1 hour and 45 minutes for this part Section II

Pages 27–37

25 marks • Attempt ONE question from Questions 28–32 • Allow about 45 minutes for this section 433

Section I 75 marks Part A – 15 marks Attempt Questions 1–15 Allow about 30 minutes for this part

Use the multiple-choice answer sheet. Select the alternative A, B, C or D that best answers the question. Fill in the response oval completely. Sample:

2+4=

(A) 2 A

(B) 6

(C) 8

B

C

(D) 9 D

If you think you have made a mistake, put a cross through the incorrect answer and fill in the new answer. A

B

C

D

If you change your mind and have crossed out what you consider to be the correct answer, then indicate the correct answer by writing the word correct and drawing an arrow as follows.

correct A

B

C

–2–

D

1

The diagram shows the trajectory of a golf ball. P

Q

Which set of arrows shows the direction of the acceleration of the ball at points P and Q respectively? At P

At Q

(A) (B) (C) (D)

2

A spaceship is travelling at a very high speed. What effects would be noted by a stationary observer? (A) Time runs slower on the spaceship and it contracts in length. (B)

Time runs faster on the spaceship and it contracts in length.

(C)

Time runs slower on the spaceship and it increases in length.

(D) Time runs faster on the spaceship and it increases in length.

3

The table shows the value of the acceleration due to gravity on the surface of Earth and on the surface of Mercury. Acceleration due to gravity (m s–2 ) Earth

9.8

Mercury

3.8

A person has a weight of 550 N on the surface of Earth. What would be the person’s weight on the surface of Mercury? (A)

56.1 N

(B)

213 N

(C)

550 N

(D) 1420 N –3–

4

The diagram shows four positions of a car on a roller coaster ride.

Direction of travel

S R

P

Q At which point during this ride would the occupant experience maximum ‘g force’? (A) P (B)

Q

(C)

R

(D) S

5

The table contains information related to two planets orbiting a distant star. Planets

Mass (kg)

Orbital radius (m)

Radius of planet (m)

Length of day (s)

Orbital period (s)

Alif

1.21 × 1025

4.00 × 1011

8.0 × 106

9.5 × 104

8.75 × 107

Ba

1.50 × 1024

8.00 × 1011

4.0 × 106

4.7 × 104

____

The orbital period of the planet Ba can be determined by using data selected from this table. What is the orbital period of the planet Ba? (A) 3.10 × 107 s (B)

5.51 × 107 s

(C)

1.39 × 108 s

(D) 2.47 × 108 s

–4–

6

What is the role of a transformer at an electrical power station? (A) To reduce heating in the transmission lines by stepping up the voltage (B)

To reduce heating in the transmission lines by stepping up the current

(C)

To increase heating in the transmission lines by stepping up the voltage

(D) To increase heating in the transmission lines by stepping up the current

7

A student performed an experiment to measure the force on a long current-carrying conductor placed perpendicular to an external magnetic field. The graph shows how the force on a 1.0 m length of the conductor varied as the current through the conductor was changed. Force (N)

0.7

3.0

Current (A)

What was the magnitude of the external magnetic field in this experiment? (A) 0.23 T (B)

1.1 T

(C)

2.1 T

(D) 4.3 T

–5–

8

A single-turn coil of wire is placed in a uniform magnetic field B, so that the plane of the coil is parallel to the field, as shown in the diagrams. The coil can move freely. An electric current I flows around the coil in the direction shown. In which direction does the coil begin to move as a consequence of the interaction between the external magnetic field and the current? (A)

(B)

B

B

I

I

(C)

(D)

B

B

I

I

–6–

9

In a student experiment, a bar magnet is dropped through a long plastic tube of length l and diameter d. The time taken for it to hit the floor is recorded. N S

d

N S

l

Plastic

d

Copper

The experiment is repeated using a copper tube of the same length and diameter. Which of the following statements is correct? (A) The magnet will take the same time to hit the floor in both cases. (B)

The magnet will come to rest in the middle of the copper tube.

(C)

The magnet will take longer to fall through the copper tube.

(D) The magnet will take longer to fall through the plastic tube.

–7–

10

The coil of an AC generator rotates at a constant rate in a magnetic field as shown. B

P

B

B

Q

B

R

S

B

T

Which of the following diagrams represents the curve of induced emf against position? (A) Q Induced emf P

R

T

Position

S

(B) T

P Induced emf

Q

S

Position

R

(C) Induced emf P

Q

S

T

R

Position

(D) P

R

T

Induced emf

Position Q

S

–8–

11

Which of the following describes an n-type semiconductor? (A) A semiconductor doped to produce extra free electrons (B)

A semiconductor doped to remove free electrons

(C)

A semiconductor doped to produce extra holes

(D) An undoped semiconductor

12

Which of the following graphs shows the behaviour of a superconducting material? (A)

(B)

Resistance (Ω) 0

Resistance (Ω) 0

Temperature (K)

(C)

Temperature (K)

(D)

Resistance (Ω) 0

Resistance (Ω) 0

Temperature (K)

–9–

Temperature (K)

13

The diagram shows the side view of a simple cathode ray tube.

+

R

Fluorescent screen

–

R

What is the function of the components labelled R? (A) To produce cathode rays (B)

To stop cathode rays striking the screen

(C)

To deflect the cathode rays vertically

(D) To deflect the cathode rays horizontally

14

During the early 1950s most transistors were manufactured using germanium. Why was germanium used instead of silicon? (A) Silicon is more brittle than germanium. (B)

Germanium could be more easily produced in a purified form.

(C)

Germanium is a more abundant raw material.

(D) Silicon does not retain its semiconductor properties at high temperatures.

– 10 –

15

A student carried out an experiment during which light of different frequencies was shone onto a metal surface to produce photoelectrons. The student measured the maximum kinetic energy of the emitted photoelectrons as the frequency of light was altered. The relationship between the maximum kinetic energy of the photoelectrons and the frequency of the light incident on the metal surface is given by: Ek(max) = hf − ø where Ek(max) = maximum kinetic energy of the photoelectrons f = frequency of light used h = Planck’s constant ø = a constant dependent on the metal used. How could the student best analyse the data to determine a value for Planck’s constant? (A) Plot Ek(max) against f and find the gradient of the line of best fit. (B)

Plot Ek(max) against ø and find the gradient of the line of best fit.

(C)

Plot Ek(max) against f and find the intercept of the line of best fit.

(D) Plot Ek(max) against ø and find the intercept of the line of best fit.

– 11 –

BLANK PAGE

– 12 – © Board of Studies NSW 2002

2002 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I (continued) Part B – 60 marks Attempt Questions 16–27 Allow about 1 hour and 45 minutes for this part Answer the questions in the spaces provided. Show all relevant working in questions involving calculations.

Question 16 (8 marks)

Please turn over

434

– 13 –

Student Number

Question 16 (8 marks) Two students, Kim and Ali, performed an experiment to determine the acceleration due to gravity (g) using a simple pendulum consisting of a small mass hanging from a light string.

L

θ

Their procedure was as follows: 1.

Adjust the length of the string (L) to measure 0.08 m.

2.

Hold the mass to the side to give a small angular displacement, θ.

3.

Release the mass and measure the time for one period (T).

4.

Record the result in a table.

5.

Repeat using a string length (L) of 0.09 m and continue until the string length is 0.19 m (going up in 0.01 m increments, using the same initial angular displacement each time). L . Calculate g using the relationship T = 2π g

6.

The results are shown in the table: L (m)

0.08 0.09 0.10 0.11 0.12 0.13 0.14 0.15 0.16 0.17 0.18 0.19

T (s)

0.57 0.62 0.65 0.67 0.70 0.73 0.76 0.80 0.81 0.84 0.86 0.89

Kim used the data in the table to obtain a mean value for g. Kim’s result was g = 9.3 m s−2. Ali used the results to produce the following graph. Ali’s line of best fit was used to calculate g. 1.2 1.0 T 2(s2)

0.8 0.6 Ali’s line of best fit

0.4 0.2 0

0.04

0.08

0.12

0.16

0.20

L (m)

Question 16 continues on page 15 – 14 –

0.24

Marks Question 16 (continued) (a)

Outline TWO changes that could be made to the experimental procedure that would improve its accuracy.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Compare Kim’s and Ali’s methods of calculating g and identify the better approach.

3

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (c)

Calculate the value of g from the line of best fit on Ali’s graph. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

End of Question 16

– 15 –

3

Marks Question 17 (4 marks) Describe TWO difficulties associated with effective or reliable communications between satellites and Earth. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 16 – © Board of Studies NSW 2002

4

2002 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 18 (3 marks) The graph shows the percentage transmission of electromagnetic radiation of various wavelengths through the Earth’s atmosphere.

% transmission through atmosphere

100 80 60 40 20 0

10–10 10–9 10–8 10–7 10–6 10–5 10–4 10–3 10–2 10–1 100 101 102 Wavelength (m)

The Voyager II spacecraft transmits electromagnetic radiation to Earth at a frequency of 2295 MHz. Use the graph to justify the use of this transmission frequency. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

435

– 17 –

3

Marks Question 19 (4 marks) In one of Einstein’s famous thought experiments, a passenger travels on a train that passes through a station at 60% of the speed of light. According to the passenger, the length of the train carriage is 22 m from front to rear. (a)

A light in the train carriage is switched on. Compare the velocity of the light beam as seen by the passenger on the train and a rail worker standing on the station platform.

1

............................................................................................................................... ............................................................................................................................... (b)

Calculate the length of the carriage as observed by the rail worker on the station platform. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 18 –

3

Marks Question 20 (3 marks) A student is investigating inertial and non-inertial frames of reference. The student carries out a series of activities on a boat floating on a large, calm lake. The boat remained level during these activities. Each activity and the student’s observed results are recorded in the table. Activity

Observation

Dropped a ball from a set height

Ball fell vertically with increasing velocity

Rolled a ball from one side of the boat to the other

Ball rolled across the floor with a constant velocity

Rolled a ball from the back of the boat towards the front of the boat

Ball rolled across the floor with a constant velocity

Justify the student’s conclusion that: ‘The boat can be regarded as an inertial frame of reference’. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 19 –

3

Marks Question 21 (4 marks) In his science fiction novel From the Earth to the Moon, Jules Verne describes how to launch a capsule from a cannon to land on the moon. To reach the moon, the capsule must leave the cannon with a speed of 1.06 × 104 m s−1. The cannon has a length of 215 m, over which the capsule can be assumed to accelerate constantly. (a)

Calculate the magnitude of the acceleration required to achieve this speed using this cannon.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Referring to your answer in part (a), explain why Jules Verne’s method is unsuitable for sending a living person to the moon. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 20 – © Board of Studies NSW 2002

2

2002 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 22 (6 marks) Two types of generator are shown in the diagram. B To external circuit

B To external circuit

Generator P (a)

Generator Q

What is the function of the brush in a generator?

1

............................................................................................................................... ............................................................................................................................... (b)

Which of these generators is a DC generator? Justify your choice.

3

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (c)

Outline why AC generators are used in large-scale electrical power production. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

436

– 21 –

2

Marks Question 23 (7 marks) (a)

1

State Lenz’s law. ............................................................................................................................... ...............................................................................................................................

(b)

When the metal rod is moved upwards through the magnetic field as shown in the diagram, an emf is induced between the two ends. Direction of motion

S

S

N

End Y

N

End X (i)

Which end of the rod is negative?

1

................................................................................................................... (ii)

Explain how the emf is produced in the rod.

3

................................................................................................................... ................................................................................................................... ................................................................................................................... ................................................................................................................... ................................................................................................................... ................................................................................................................... (c)

Explain how the principle of induction can be used to heat a conductor. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 22 – © Board of Studies NSW 2002

2

2002 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 24 (8 marks) In terms of band structures and relative electrical resistance, describe the differences between a conductor, an insulator and a semiconductor. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

437

– 23 –

8

Marks Question 25 (6 marks) A pair of parallel metal plates, placed in a vacuum, are separated by a distance of 5.00 × 10−3 m and have a potential difference of 1000 V applied to them. (a)

Calculate the magnitude of the electric field strength between the plates.

1

............................................................................................................................... ............................................................................................................................... (b)

Calculate the magnitude of the electrostatic force acting on an electron between the plates.

1

............................................................................................................................... ............................................................................................................................... (c)

A beam of electrons is fired with a velocity of 3.00 × 106 m s−1 between the plates as shown. A magnetic field is applied between the plates, sufficient to cancel the force on the electron beam due to the electric field.

+ 1000 V −

Beam of electrons

Calculate the magnitude and direction of the magnetic field required between the plates to stop the deflection of the electron beam. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 24 –

4

Marks Question 26 (3 marks) Some materials become superconductors when cooled to extremely low temperatures. Identify THREE properties of superconductors.

3

......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

Question 27 (4 marks) There are two areas in which energy savings can be made by the use of superconductors. These are: • electricity generation and transmission; • transportation. Discuss how energy savings can be achieved in each of these two areas. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 25 –

4

BLANK PAGE

– 26 – © Board of Studies NSW 2002

2002 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics Section II 25 marks Attempt ONE question from Questions 28–32 Allow about 45 minutes for this section Answer the question in a writing booklet. Extra writing booklets are available. Show all relevant working in questions involving calculations.

Pages

438

Question 28

Geophysics ........................................................................... 28–29

Question 29

Medical Physics ................................................................... 30–31

Question 30

Astrophysics ......................................................................... 32–33

Question 31

From Quanta to Quarks ....................................................... 34–35

Question 32

The Age of Silicon ............................................................... 36–37

– 27 –

Marks Question 28 — Geophysics (25 marks) (a)

(i)

Describe Earth’s current magnetic field.

2

(ii)

The diagram represents the magnetic anomalies of the oceanic crust located near the island of Iceland in the mid-Atlantic.

4

Mid-ocean ridge Explain the origin of the pattern of magnetic anomalies on either side of the mid-ocean ridge.

(b)

2

(i)

Recount the steps involved in gravity data reduction.

(ii)

The diagram shows the surface height and gravity anomaly curve in a region near the Red Sea.

Gravity anomaly

Height (metres) WEST

EAST

2000

+100

1000 X

0

Y

Sea level

−100 0

100

200

300

400

500

600 km

Key Land mass

Red Sea

Gravity anomaly curve

(1) Propose reasons for the difference in the gravity anomaly at the locations marked X and Y.

2

(2) Predict the likely variation in orbital path for a satellite moving from West to East across the region shown in the diagram.

2

Question 28 continues on page 29 – 28 –

Marks Question 28 (continued) (c)

The graph shows the travel time for P waves and S waves at different surface distances from an earthquake epicentre.

25

Travel time (minutes)

P' P''

20 S

P''

15

10 P 5

0

5000

10 000

15 000

20 000

Surface distance from epicentre (km)

(d)

(i)

Contrast the properties of P waves and S waves.

2

(ii)

Account for the absence of S waves at distances greater than 11 000 km from the earthquake epicentre.

2

(iii)

Identify how this graph supports the existence of a solid inner core of Earth.

2

Assess the application and advantages of TWO geophysical methods in mineral exploration.

7

End of Question 28

– 29 –

Marks Question 29 — Medical Physics (25 marks)

(b)

(i)

Briefly describe how an endoscope works.

2

(ii)

Explain how a computed axial tomography (CAT) scan is produced.

4

Technetium 99m is an artificial isotope which is frequently used to obtain a scan of the human body. (i)

Using the graph, determine the half life of technetium 99m.

1

100

% of technetium 99m remaining in sample

(a)

75

50

25

0 0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 Time (hours) (ii)

A patient is given an injection containing 6.0 × 10−18 kg of technetium 99m. The scan is taken four hours after the injection.

2

How much technetium 99m remains undecayed when the scan is taken? (Give your answer in kilograms.) (iii)

Propose reasons why scans are best taken between two and five hours after injection of this radioisotope.

Question 29 continues on page 31

– 30 –

3

Marks Question 29 (continued) (c)

The diagrams shown are an MRI of the human upper arm, an X-ray of a human hand and a CAT scan of the human pelvis (hip bone) as seen in cross-section from above.

MRI of human upper arm Procedure time: 30–60 minutes

X-ray of human hand Procedure time: 5 minutes

CAT scan of human pelvis (hipbone) Procedure time: 40 minutes

(i)

Identify TWO advantages of MRI scans over CAT scans.

2

(ii)

A patient is brought into a hospital out-patients ward complaining of a severe headache. He explains that he hit his head while playing football. The doctor thinks that the patient may be suffering from a fractured skull.

2

Explain why the doctor would order an X-ray to confirm the diagnosis of a fractured skull. (iii)

The patient, now diagnosed with a fractured skull, complains of other symptoms that may indicate that he is suffering from brain damage.

2

Suggest ONE additional scan which may be required to confirm this diagnosis. Justify your choice.

(d)

Assess the impact of medical applications based on ultrasound and the magnetic field of particles within the body on modern society.

End of Question 29

– 31 –

7

Marks Question 30 — Astrophysics (25 marks) (a)

(i)

2

The star Algol is an eclipsing binary as viewed from Earth. Describe the observations made by astronomers to identify a star as an eclipsing binary.

(ii)

4

Binary stars are important in determining stellar masses. Explain how the total mass of a binary star system can be calculated.

(b)

The table gives information about various nearby stars. Star

Distance (parsecs)

Apparent visual magnitude

Colour Index

Proxima Centauri

1.29

11.01

1.90

Barnard’s Star

1.82

9.54

1.74

Lalande 21185

2.55

7.49

1.51

Ross 154

2.97

10.37

1.75

(i)

Which star from the table is the most blue in colour?

1

(ii)

Calculate how much brighter Ross 154 is than Proxima Centauri when viewed from Earth.

2

(iii)

Sketch a labelled diagram indicating the information required to use the trigonometric parallax method to determine the distance to Barnard’s Star.

3

Question 30 continues on page 33

– 32 –

Marks Question 30 (continued) (c)

An H-R diagram can be used to show the evolutionary track of stars.

R

104 103

in se

qu

102

e

nc

10 1

e

S 100 000

(d)

Q

ma

Solar luminosities

105

P

30 000 10 000 3000 Surface Temperature (K)

(i)

Select the position P, Q, R or S on the H-R diagram in which white dwarfs would be found. Justify your choice.

2

(ii)

A white dwarf is considered to be in a stable condition. Explain why a white dwarf does not continue to shrink in size.

2

(iii)

Describe ONE nuclear reaction taking place in a star located on the main sequence.

2

Discuss how the development of adaptive optics and at least one other development have improved resolution and sensitivity of ground based astronomy.

7

End of Question 30

– 33 –

Marks Question 31 — From Quanta to Quarks (25 marks) (a)

(b)

(i)

Describe Davisson and Germer’s experiment that confirmed the de Broglie hypothesis of wave-particle duality.

2

(ii)

Explain the stability of the electron orbits in the Bohr atom, using de Broglie’s hypothesis.

4

The diagram shows the kinetic energy distribution of the electrons emitted in the 210 β-decay of 210 83 Bi into 84 Po. The energy released during β-decay depends on the mass defect in the transmutation, as it does in nuclear fission.

Relative number of electrons

9 Nucleus or particle

8 7 6 5 4

Mass (amu)

210Bi

209.938 57

210Po

209.936 78

e

0.000 55

3 2

End-point Ek(max)

1 0

0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0 1.1 1.2 1.3 Kinetic energy of electrons, Ek (MeV)

(i)

Identify the scientist who suggested that the existence of the neutrino relates to the need to account for the energy distribution of electrons emitted in β-decay.

1

(ii)

Use the data to calculate the mass defect in the β-decay of (Assume that the neutrino is a massless particle.)

210 83 Bi.

2

(iii)

Account for the energy distribution of electrons emitted in this β-decay.

3

Question 31 continues on page 35

– 34 –

Marks Question 31 (continued) (c)

The diagram represents the four spectral lines in the visible region of the hydrogen spectrum known as the Balmer Series.

Hδ

(d)

Hγ

Hβ

Hα

410 434

486

656

NOT TO SCALE

Wavelength (nm)

(i)

Explain how the Balmer Series provides strong experimental evidence in support of Bohr’s model of the hydrogen atom.

3

(ii)

Calculate the wavelength of the next line in the Balmer Series.

3

Discuss how neutron scattering and ONE other process have been used to increase our understanding of the structure of matter.

End of Question 31

– 35 –

7

Marks Question 32 — The Age of Silicon (25 marks)

(b)

(i)

Describe the structure of an LED.

2

(ii)

Explain why, in some applications, it is preferable to use an LED rather than an ordinary light source.

4

(i)

The diagram shows how the resistance of a light-dependent resistor (LDR) depends on the intensity of the light falling on it (illumination). 2000 1800 1600 LDR resistance (Ω)

(a)

1400 1200 1000 800 600 400 200 0

(ii)

0

2

4 6 Illumination (lux)

8

10

(1) Describe qualitatively how the resistance of this LDR changes as the illumination increases.

1

(2) What is the resistance of this LDR when the intensity of light falling on it is 4 lux?

1

This LDR is connected in series with the coil of a relay to a 12 volt power supply as shown.

4

12 V

LDR Coil of relay

This relay switches on when the current through the coil reaches 4.8 mA. When connected in this circuit, the relay switches on when the illumination on the LDR is 2 lux. Calculate the resistance of the coil of the relay. Question 32 continues on page 37 – 36 –

Marks Question 32 (continued) (c)

The table gives the output voltage of an amplifier as a function of the input voltage. Input voltage (microvolt) –300 –250 –200 –150 –100 –50 0 50 100 150 200 250 300

(d)

Output voltage (volt) 8.0 8.0 8.0 6.0 4.0 2.0 0.0 –2.0 –4.0 –6.0 –8.0 –8.0 –8.0

(i)

Describe the properties of an ideal amplifier.

2

(ii)

Calculate the gain of this amplifier.

2

(iii)

Propose why this amplifier is not suitable for input signals that vary from −250 microvolt to +250 microvolt.

2

Early computers used thermionic devices. Later computers used transistors and today computers use integrated circuits. Discuss the impact and limitations of these developments.

7

End of paper

– 37 –

BLANK PAGE

– 38 – © Board of Studies NSW 2002

2002 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics DATA SHEET Charge on the electron, qe

–1.602 × 10–19 C

Mass of electron, me

9.109 × 10–31 kg

Mass of neutron, mn

1.675 × 10–27 kg

Mass of proton, mp

1.673 × 10–27 kg

Speed of sound in air

340 m s–1

Earth’s gravitational acceleration, g

9.8 m s–2

Speed of light, c

3.00 × 108 m s–1

µ Magnetic force constant,  k ≡ 0  2π  

2.0 × 10–7 N A–2

Universal gravitational constant, G

6.67 × 10–11 N m2 kg–2

Mass of Earth

6.0 × 1024 kg

Planck’s constant, h

6.626 × 10–34 J s

Rydberg’s constant, RH

1.097 × 107 m–1

Atomic mass unit, u

1.661 × 10–27 kg 931.5 MeV/ c 2

439

1 eV

1.602 × 10–19 J

Density of water, ρ

1.00 × 103 kg m–3

Specific heat capacity of water

4.18 × 103 J kg–1 K–1

– 39 –

FORMULAE SHEET c = fλ Intensity

Gm1 m2

F=−

∝

r2

1 d2

r3 T2

v1 sin i = v2 sin r

GM

=

4π 2

m1 + m2 = E=

R=

F q

4π 2 r 3 GT 2

d M = m − 5 log   10

V I

IA

P = VI

= 100

IB

(mB − mA )

Energy = VIt d=

1 p

r t where r = displacement

vav = ∆

F = BIl sin θ

aav

F

∆v v − u = = ∆t t

l

Σ F = ma Ek =

=k

I1 I2 d

τ = Fd

1 2 mv 2

τ = nBIA cosθ

p = mv

Vp

∆ p = Ft

Vs

– 40 –

=

np ns

5

FORMULAE SHEET Ep = −

F = qvB sin θ

Gm1 m2 r

E =

v = u + at

E = hf

v x 2 = ux 2 v y 2 = uy 2 + 2 ay ∆ y

Z = ρv

∆ x = ux t

Ir Io

1 2

∆ y = uy t + ay t 2 s u+v = t 2

2 Z2 − Z1 ] [ = [ Z2 + Z1 ] 2

 1 1 1 = RH  2 − 2  λ  n f ni 

lv = lo 1 −

tv =

V d

v2 c2

λ =

h mv

to 1−

v2 c2

Amplifier gain =

Ao =

– 41 –

Vo V+ − V−

Vout Vin

– 42 –

Yttrium

57–71

56 Ba 137.3

Barium

88 Ra [226.0]

Radium

Caesium

87 Fr [223.0]

Francium

Rutherfordium

104 Rf [261.1]

Hafnium

90 Th 232.0

Thorium

Actinides 89 Ac [227.0]

Actinium

Protactinium

91 Pa 231.0

Praseodymium

59 Pr 140.9

Dubnium

105 Db [262.1]

Tantalum

73 Ta 180.9

Niobium

Uranium

92 U 238.0

Neodymium

60 Nd 144.2

Seaborgium

106 Sg [263.1]

Tungsten

74 W 183.8

Molybdenum

Neptunium

93 Np [237.0]

Promethium

61 Pm [146.9]

Bohrium

107 Bh [264.1]

Rhenium

75 Re 186.2

Technetium

43 Tc [98.91]

Manganese

Plutonium

94 Pu [239.1]

Samarium

Americium

95 Am [241.1]

Europium

63 Eu 152.0

Curium

96 Cm [244.1]

Gadolinium

64 Gd 157.3

Ununnilium

Meitnerium

Hassium

62 Sm 150.4

110 Uun —

109 Mt [268]

108 Hs [265.1]

Platinum

78 Pt 195.1

Palladium

46 Pd 106.4

Nickel

28 Ni 58.69

Iridium

77 Ir 192.2

Rhodium

45 Rh 102.9

Cobalt

27 Co 58.93

111 Uuu —

Gold

79 Au 197.0

Silver

47 Ag 107.9

Copper

29 Cu 63.55

Berkelium

97 Bk [249.1]

Terbium

65 Tb 158.9

Unununium

Name of element

Osmium

76 Os 190.2

Ruthenium

44 Ru 101.1

Iron

26 Fe 55.85

Atomic Weight

Symbol of element

Californium

98 Cf [252.1]

Dysprosium

66 Dy 162.5

Ununbium

112 Uub —

Mercury

80 Hg 200.6

Cadmium

48 Cd 112.4

Zinc

30 Zn 65.39

Einsteinium

99 Es [252.1]

Holmium

67 Ho 164.9

113

Thallium

81 Tl 204.4

Indium

49 In 114.8

Gallium

31 Ga 69.72

Aluminium

13 Al 26.98

Boron

5 B 10.81

Fermium

100 Fm [257.1]

Erbium

68 Er 167.3

Ununquadium

114 Uuq —

Lead

82 Pb 207.2

Tin

50 Sn 118.7

Germanium

32 Ge 72.61

Silicon

14 Si 28.09

Carbon

6 C 12.01

Mendelevium

101 Md [258.1]

Thulium

69 Tm 168.9

115

Bismuth

83 Bi 209.0

Antimony

51 Sb 121.8

Arsenic

33 As 74.92

Phosphorus

15 P 30.97

Nitrogen

7 N 14.01

Where the atomic weight is not known, the relative atomic mass of the most common radioactive isotope is shown in brackets. The atomic weights of Np and Tc are given for the isotopes 237Np and 99Tc.

Cerium

Lanthanum

Lanthanides 57 58 La Ce 138.9 140.1

Actinides

89–103

Lanthanides

72 Hf 178.5

Zirconium

42 Mo 95.94

Chromium

Strontium

41 Nb 92.91

Vanadium

55 Cs 132.9

40 Zr 91.22

Rubidium

Titanium

39 Y 88.91

38 Sr 87.62

Scandium

Calcium

37 Rb 85.47

25 Mn 54.94

Potassium

24 Cr 52.00

20 Ca 40.08

19 K 39.10

23 V 50.94

Magnesium

Sodium

22 Ti 47.87

12 Mg 24.31

11 Na 22.99

21 Sc 44.96

Beryllium

Lithium Gold

79 Au 197.0

4 Be 9.012

3 Li 6.941 Atomic Number

KEY

PERIODIC TABLE OF THE ELEMENTS

Hydrogen

1 H 1.008

Nobelium

102 No [259.1]

Ytterbium

70 Yb 173.0

Ununhexium

116 Uuh —

Polonium

84 Po [210.0]

Tellurium

52 Te 127.6

Selenium

34 Se 78.96

Sulfur

16 S 32.07

Oxygen

8 O 16.00

Lawrencium

103 Lr [262.1]

Lutetium

71 Lu 175.0

117

Astatine

85 At [210.0]

Iodine

53 I 126.9

Bromine

35 Br 79.90

Chlorine

17 Cl 35.45

Fluorine

9 F 19.00

Ununoctium

118 Uuo —

Radon

86 Rn [222.0]

Xenon

54 Xe 131.3

Krypton

36 Kr 83.80

Argon

18 Ar 39.95

Neon

10 Ne 20.18

Helium

2 He 4.003

2003 H I G H E R S C H O O L C E R T I F I C AT E E X A M I N AT I O N

Physics

Total marks – 100 General Instructions • Reading time – 5 minutes • Working time – 3 hours • Write using black or blue pen • Draw diagrams using pencil • Board-approved calculators may be used • A data sheet, formulae sheets and Periodic Table are provided at the back of this paper • Write your Centre Number and Student Number at the top of pages 13, 17, 21 and 25

Section I

Pages 2–28

75 marks This section has two parts, Part A and Part B Part A – 15 marks • Attempt Questions 1–15 • Allow about 30 minutes for this part Part B – 60 marks • Attempt Questions 16–27 • Allow about 1 hour and 45 minutes for this part Section II

Pages 29–42

25 marks • Attempt ONE question from Questions 28–32 • Allow about 45 minutes for this section 433

Section I 75 marks Part A – 15 marks Attempt Questions 1–15 Allow about 30 minutes for this part

Use the multiple-choice answer sheet. Select the alternative A, B, C or D that best answers the question. Fill in the response oval completely. Sample:

2+4=

(A) 2 A

(B) 6

(C) 8

B

C

(D) 9 D

If you think you have made a mistake, put a cross through the incorrect answer and fill in the new answer. A

B

C

D

If you change your mind and have crossed out what you consider to be the correct answer, then indicate the correct answer by writing the word correct and drawing an arrow as follows.

correct A

B

C

–2–

D

1

1 The weight of an astronaut on the Moon is – of her weight on Earth. 6 What is the acceleration due to gravity on the Moon? 6 (A)   m s −2  9.8  (B)

 9.8  m s −2  6 

(C)

9.8 m s −2

(D) (9.8 × 6) m s −2 2

A satellite moves in uniform circular motion around Earth. The following table shows the symbols used in the diagrams below. These diagrams are NOT drawn to scale. Key F

net force on satellite

v

velocity of satellite

Which diagram shows the direction of F and v at the position indicated? Satellite

(A)

F

v

F

v

Earth

Earth

Satellite

(C)

Satellite

(B)

Satellite

(D)

F v

v F Earth

Earth

–3–

3

For a satellite moving in uniform circular motion around Earth, the centripetal force is provided by the gravitational force. The mass of Earth is ME . The mass of the satellite is MS . The distance of the satellite from the centre of Earth is d. Which of the following equations should be used to calculate the speed of this satellite? GME d

(A)

v=

(B)

v=

GME d

(C)

v=

GME d

(D)

4

v=

2

GME MS d

Two planets, X and Y, travel around a star in the same direction, in circular orbits. Planet X completes one revolution about the star in time T. The radii of the orbits are in the ratio 1 : 4.

Y 4r

r X

How many revolutions does planet Y make about the star in the same time T? (A) –18 revolution (B) –12 revolution (C)

2 revolutions

(D) 8 revolutions –4–

5

An astronaut set out in a spaceship from Earth orbit to travel to a distant star in our galaxy. The spaceship travelled at a speed of 0.8 c. When the spaceship reached the star the on-board clock showed the astronaut that the journey took 10 years. An identical clock remained on Earth. What time in years had elapsed on this clock when seen from the astronaut’s spaceship? (A)

3.6

(B)

6.0

(C)

10.0

(D) 16.7

The diagram shows a DC generator connected to a cathode ray oscilloscope (CRO).

N S

CRO

What output voltage would be observed for this generator on the CRO?

0

Time (s)

(C)

Voltage (V)

(B)

0

Time (s)

0

Time (s)

(D)

0

Time (s)

–5–

Voltage (V)

Voltage (V)

(A)

Voltage (V)

6

7

A non-magnetic metal disk is balanced on a support as shown in the diagram below. The disk is initially stationary. A magnet is moved in a circular path just above the surface of the disk, without touching it. Path

S

N Disk

As a result of this movement the disk begins to rotate in the same direction as the magnet. The observed effect demonstrates the principle most applicable to the operation of the (A) DC motor. (B)

galvanometer.

(C)

generator.

(D) induction motor.

8

A neon sign requires a 6000 V supply for its operation. A transformer allows the neon sign to operate from a 240 V supply. What is the ratio of the number of secondary turns to the number of primary turns for the transformer? (A)

1 : 40

(B)

1 : 25

(C)

25 : 1

(D)

40 : 1

–6–

9

A current of 5.0 A flows in a wire that is placed in a magnetic field of 0.5 T. The wire is 0.7 m long and is at an angle of 60° to the field. B = 0.5 T

0.7 m

I = 5.0 A

60°

What is the approximate magnitude of the force on the wire? (A)

0N

(B)

0.9 N

(C)

1.5 N

(D)

1.8 N

–7–

10

A flexible wire loop is lying on a frictionless table made from an insulating material. The wire can slide around horizontally on the table and change shape freely, but it cannot move vertically. The loop is connected to a power supply, a switch and two terminals fixed to the table as shown.

Wire loop

Switch

When the switch is closed, a current I flows around the loop. Which of the following diagrams most closely represents the final shape of the loop after the switch is closed? (A)

(B) I

I

(C)

(D)

I

I

–8–

11

Which of the following did the Braggs investigate using X-ray diffraction? (A) Cathode rays (B)

Crystal structure

(C)

Photoelectric effect

(D) Superconductivity

12

In a first-hand investigation that you performed, you used a discharge tube containing a Maltese Cross. You would have observed an image similar to the one shown below.

Which of the following statements is a valid conclusion from the observations made in this Maltese Cross investigation? (A) Cathode rays pass through glass. (B)

Cathode rays pass through metals.

(C)

Cathode rays are charged particles.

(D) Cathode rays travel in straight lines.

–9–

13

An n-type semiconductor is produced when silicon crystal is doped with small quantities of phosphorus. How will this doping change the crystal’s electrical conductivity? (A) The conductivity will decrease because there are fewer holes in the valence band. (B)

The conductivity will increase because there are more holes in the valence band.

(C)

The conductivity will decrease because there are fewer electrons in the conduction band.

(D) The conductivity will increase because there are more electrons in the conduction band.

14

Heinrich Hertz used a set-up similar to the one shown below to investigate the production and detection of electromagnetic radiation. Transmitter

Receiver

High voltage source of radio waves

A glass sheet was placed between the transmitter and receiver. Which of the following observations is consistent with the photoelectric effect that Hertz produced? (A) Radio waves were blocked when the glass sheet was in place. (B)

Ultraviolet waves were blocked when the glass sheet was in place.

(C)

The maximum spark length was longer when the glass sheet was in place.

(D) The maximum spark length was shorter when the glass sheet was in place.

– 10 –

15

A positively-charged ion travelling at 250 m s−1 is fired between two parallel charged plates, M and N. There is also a magnetic field present in the region between the two plates. The direction of the magnetic field is into the page as shown. The ion is travelling perpendicular to both the electric and the magnetic fields. M

N The electric field between the plates has a magnitude of 200 V m−1. The magnetic field is adjusted so that the ion passes through undeflected. What is the magnitude of the adjusted magnetic field, and the polarity of the M terminal relative to the N terminal? Magnitude of magnetic field (teslas)

Polarity of M relative to N

(A)

0.8

positive

(B)

0.8

negative

(C)

1.25

positive

(D)

1.25

negative

– 11 –

BLANK PAGE

– 12 – © Board of Studies NSW 2003

2003 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I (continued) Part B – 60 marks Attempt Questions 16–27 Allow about 1 hour and 45 minutes for this part Answer the questions in the spaces provided. Show all relevant working in questions involving calculations.

Question 16 (6 marks)

Please turn over

434

– 13 –

Student Number

Marks Question 16 (6 marks) A student performed a first-hand investigation to examine projectile motion. A ball resting on a horizontal table was given an initial push at X, resulting in the ball following the path XYZ as shown. Motion sensor

X

Y

NOT TO SCALE

Z

Range A data logger used the motion sensor to measure the horizontal distance to the ball. When the ball was at position Y, a distance of 1.50 m from the motion sensor, it left the edge of the table. In the first trial, the range was 0.60 m. The graph below was obtained from the data logger. 2.0

Distance (m)

1.5

1.0 Linear fit: y = mx + b m (slope): 1.85 b (y-intercept): 0.512 Correlation: 1.00

0.5

0

0

0.2

0.4 0.6 Time (s)

0.8

Question 16 continues on page 15 – 14 –

Marks Question 16 (continued) (a)

For this trial, determine the horizontal speed of the ball as it left the edge of the table.

1

............................................................................................................................... ............................................................................................................................... (b)

The experiment was repeated with the ball leaving the table at different speeds. Graph the relationship between the range and the horizontal speed at Y. Identify on your graph the results from the first trial.

3

0

(c)

The apparatus described in this first-hand investigation was used to carry out an identical experiment on another planet where the acceleration due to gravity is less than that on Earth. The horizontal speed of the ball as it left the table on the planet was the same as in part (a). Compare the range of the ball on the planet to that on Earth. Explain your answer. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... End of Question 16 – 15 –

2

Marks Question 17 (6 marks) A satellite of mass 150 kg is launched from Earth’s surface into a uniform circular orbit of radius 7.5 × 106 m. (a)

Calculate the magnitude of the gravitational potential energy Ep of the satellite.

1

............................................................................................................................... ............................................................................................................................... (b)

3

From this uniform circular orbit, the satellite can escape Earth’s gravitational field when its kinetic energy is equal to the magnitude of the gravitational potential energy. Use this relationship to calculate the escape velocity of the satellite. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

(c)

Discuss the effect of Earth’s rotational motion on the launch of this satellite. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 16 – © Board of Studies NSW 2003

2

2003 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 18 (6 marks) Michelson and Morley set up an experiment to measure the velocity of Earth relative to the aether. (a)

Outline TWO features of the aether model for the transmission of light.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Recount the Michelson and Morley experiment, which attempted to measure the relative velocity of Earth through the aether, and describe the results they anticipated. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

435

– 17 –

4

Marks Question 19 (3 marks) Two straight copper wires are suspended so that their lower ends dip into a conducting salt solution in a beaker as shown. The length of the straight section of each wire above the conducting salt solution is 35 cm and they are placed 1.5 cm apart. The ends of the wire do not touch the bottom of the beaker. The two wires are connected to a DC power supply.

1.5 cm 35 cm

NOT TO SCALE

Conducting salt solution A current of 2 amperes flows from the battery. Calculate the magnitude and direction of the initial force on each wire. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 18 –

3

Marks Question 20 (4 marks) Two solenoids (coils) with hollow cores are suspended using string so that they are hanging in the positions shown below. The solenoids are free to move in a pendulum motion.

Support

Support

Copper wire A

B

A

N

Figure 1 – First investigation

S

B

N

S

Figure 2 – Second investigation

In the first investigation shown in Figure 1, a strong bar magnet is moved towards the solenoid until the north end of the magnet enters the solenoid and then the motion of the magnet is stopped. In the second investigation, shown in Figure 2, a thick copper wire is connected between the two terminals, A and B, at the ends of the solenoid. The motion of the magnet is repeated exactly in this second investigation. Explain the effect of the motion of the magnet on the solenoid in the two investigations. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 19 –

4

BLANK PAGE

– 20 – © Board of Studies NSW 2003

2003 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 21 (5 marks) (a)

Explain the relationship between the current in the primary coil and the current in the secondary coil of an ideal step-down transformer in relation to the conservation of energy.

3

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Explain why a transformer will work in an AC circuit but not in a DC circuit. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

436

– 21 –

2

Marks Question 22 (5 marks) Describe a first-hand investigation to demonstrate the effect on a generated electric current when the strength of the magnet is varied. In your description, include: • a labelled sketch of the experimental set-up; • how you varied the magnetic field strength; • how other variables were controlled.

......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 22 –

5

Marks Question 23 (6 marks) (a)

The following image shows a magnet hovering above a superconducting disk.

3

Explain why the magnet is able to hover above the superconductor. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Compare the model for the conduction of electricity in metals at room temperature with the model for conduction of electricity in superconductors below the critical temperature. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 23 –

3

BLANK PAGE

– 24 – © Board of Studies NSW 2003

2003 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 24 (4 marks) Outline Thomson’s experiment to measure the charge/mass ratio of an electron. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

437

– 25 –

4

Marks Question 25 (5 marks) A physics student was conducting an investigation on the photoelectric effect. The student used an infrared laser with a wavelength of 1.55 × 10−6 m for this investigation. (a)

Calculate the energy of a photon from this laser.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

When the laser light was shone onto a photo-cell, no current was detected. The student increased the intensity of the light but still detected no current. Explain this observation. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 26 –

3

Marks Question 26 (6 marks) Describe Einstein’s contributions to Special Relativity and to Quantum Theory and how these contributions changed the direction of scientific thinking in the Twentieth Century. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 27 –

6

Marks Question 27 (4 marks) In a particle accelerator called a synchrotron, magnetic fields are used to control the motion of an electron so that it follows a circular path of fixed radius. Describe the changes required in the magnetic field to accelerate an electron to near the speed of light. Support your answer with appropriate mathematical relationships. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 28 – © Board of Studies NSW 2003

4

2003 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics Section II 25 marks Attempt ONE question from Questions 28–32 Allow about 45 minutes for this section Answer the question in a writing booklet. Extra writing booklets are available. Show all relevant working in questions involving calculations.

Pages

438

Question 28

Geophysics ........................................................................... 31–33

Question 29

Medical Physics ................................................................... 34–35

Question 30

Astrophysics ......................................................................... 36–38

Question 31

From Quanta to Quarks ....................................................... 39–40

Question 32

The Age of Silicon ............................................................... 41–42

– 29 –

BLANK PAGE

– 30 –

Marks Question 28 — Geophysics (25 marks) (a)

(b)

(c)

(i)

Identify THREE principal methods used by geophysicists to investigate the structure of Earth and the properties of Earth materials.

1

(ii)

Describe the role that geophysicists play in the monitoring of nuclear test-ban treaties.

2

Summarise the geophysical evidence that supports the theory of plate tectonics.

3

(i)

Describe how absorption and reflection of radiation can provide information about a reflecting surface.

2

(ii)

The picture below shows a satellite image of a bushfire burning in a forested area. Images such as the one below can be used as a part of the process of monitoring changes in vegetation.

3

Burnt land

Smoke

Explain how remote-sensing techniques can be used to monitor the spread of a bushfire, and the regrowth of vegetation in regions affected by a bushfire.

Question 28 continues on page 32 – 31 –

Marks Question 28 (continued) (d)

(i)

Outline the structure and function of a geophone.

(ii)

The method of seismic refraction is depicted in the diagram below. A series of eight geophones, G1 to G8, are arranged in a straight line along level ground. They are each separated by a distance of 10 m. At a distance of 20 m from the first geophone, a hammer is used to strike the ground to produce seismic waves. The geophones are attached to a seismograph that records the time of arrival of the waves after the hammer strikes the ground. Geophones

Hammer

G1 G2 G3 G4 G5 G6 G7 G8 20 m

10 m

Soft rock Hard rock

The data from the geophones are analysed and the arrival times of the direct and refracted waves that reach each geophone are recorded. These data are shown in the graph on page 33. On the graph, a circle represents the arrival of the first wave to reach a geophone, and a square represents the arrival time of the second wave to reach a geophone. The points on the graph associated with the direct seismic wave and the refracted seismic wave are shown.

Question 28 continues on page 33

– 32 –

2

Marks Question 28 (continued)

Time after hammer impact (second)

0.16 0.14 0.12 0.10 0.08 0.06 0.04 0.02 0

0

10

20 G1

30 40 50 60 70 80 G2 G3 G4 G5 G6 G7 Distance to geophones (metres)

90 G8

Legend Time of arrival of first wave at geophone Time of arrival of second wave at geophone Refracted wave Direct wave

(e)

(1) Explain why the line for the refracted wave crosses the line for the direct wave on the graph.

2

(2) From the graph, calculate the speed of the direct wave in the soft rock layer.

2

Outline the application of Newton’s theory of universal gravitation to the field of geophysics, and discuss how information obtained from gravity surveys has led to a greater understanding of the structure of Earth.

8

End of Question 28

– 33 –

Marks Question 29 — Medical Physics (25 marks) (i)

Identify the property of the hydrogen nucleus that makes it useful in magnetic resonance imaging.

1

(ii)

Describe how X-rays are produced when electrons strike the anode in an X-ray tube.

2

(b)

Outline the production of gamma rays and their use in the diagnostic procedure of positron emission tomography (PET).

3

(c)

This question refers to the bone scan of a person with cancer, and a chest X-ray of a healthy person.

(a)

Bone-scan image

X-ray image

(i)

Compare how radiation is used to produce a bone scan image and an X-ray image.

3

(ii)

Describe how a bone scan is able to provide information that an X-ray cannot provide.

2

Question 29 continues on page 35

– 34 –

Marks Question 29 (continued) (d)

The table below shows the speed of sound in, and density of, several different tissues. Speed of sound in tissue (m s−1)

Density (kg m−3)

Fat

1450

952

Blood

1570

1025

Kidney

1560

1038

Liver

1550

1065

Muscle

1580

1076

Tissue

(e)

(i)

Calculate the acoustic impedance of kidney tissue.

1

(ii)

Ultrasound travelling through kidney tissue in the body encounters a different type of tissue. Identify the type of tissue that will result in the greatest proportion of the incident pulse being reflected at the boundary between the kidney and the other tissue. Justify your choice.

2

(iii)

Describe the properties of ultrasound that led to its use in the measurement of bone density.

3

An understanding of the properties of electrons, and our ability to control their behaviour, have played key roles in the development of CAT scans and positron emission tomography imaging technologies.

8

Justify this statement with reference to the production and display of images used for medical diagnosis.

End of Question 29

– 35 –

Marks Question 30 — Astrophysics (25 marks)

(b)

(i)

Define the term resolution of a telescope.

1

(ii)

Describe ONE method by which the resolution of a ground-based system can be improved.

2

An H-R diagram for the globular cluster M3 is shown below. 12

14 Apparent magnitude

(a)

Lyrae Gap

16

18

20

10 000

7 500

5 000

Temperature (K) The stars in the Lyrae gap have an absolute magnitude of 0.6. Use this information and their position on the H-R diagram to determine the distance of M3 from Earth.

Question 30 continues on page 37

– 36 –

3

Marks Question 30 (continued) (c)

The diagram below is a comparison of the spectrum of quasar 3C 273 and a spectrum from a light source on Earth. Hγ

Hδ

Hβ

3C 273 Comparison spectrum on Earth Hδ

Hγ

Hβ

400 nm

500 nm

600 nm

(i)

From this comparison, identify the feature of the quasar spectrum that is representative of the spectra produced by quasars.

(ii)

The spectra above are both examples of absorption spectra.

1

(1) Account for the production of a star’s absorption spectrum.

2

(2) Describe how a spectrum from a star can provide information on the surface temperature of that star. Give a specific example to illustrate your answer.

2

Question 30 continues on page 38

– 37 –

Marks Question 30 (continued) (d)

The H-R diagram for a cluster is shown below. −10

1 000 000

−5 Cluster

100

0

Star X

Main s eque nce

1

+5 Star Z

0.01

+10 +15

0.0001 0. 000 001

(e)

Apparent magnitude

Luminosity (Sun = 1)

10 000

O

B

A F Spectral class

G

K

M

+20

(i)

Why is the cluster considered young?

(ii)

Stars X and Z are both part of the same cluster but have different main sequence nuclear reactions and different evolutionary pathways.

1

(1) Contrast the fusion reactions in star X and star Z.

2

(2) Predict TWO possible evolutionary pathways for star X.

3

Evaluate the impact of studying the visible spectrum of light on our understanding of celestial objects.

End of Question 30

– 38 –

8

Marks Question 31 — From Quanta to Quarks (25 marks) (a)

(b)

(i)

Identify the structure of the Rutherford model of the atom.

1

(ii)

Describe how Bohr refined Rutherford’s model of the hydrogen atom.

2

The table below shows the different types of quarks and their charge. Quark

3

Charge

Up

+ –23 e

Down

− –13 e

Strange

− –13 e

Charm

+ –23 e

Bottom

− –13 e

Top

+ –23 e

The standard model of matter says that protons and neutrons are composed of up and down quarks. There are three quarks in each particle. Compare protons and neutrons in terms of their quark composition.

(c)

The equations shown below describe three different types of transmutation reactions involving uranium. (1)

238 92

U

(2)

238 92

U

(3)

235 92

U

+

+

1 0

1 0

n

n

→

239 92

U

→

234 90

Th +

4 2

→

141 56

Ba +

92 Kr 36

He +

3 10 n

(i)

Identify which reaction is naturally occurring, and justify your answer.

2

(ii)

Identify ONE transmutation reaction above that has a practical application, and describe the application.

3

Question 31 continues on page 40

– 39 –

Marks Question 31 (continued) (d)

The two graphs below show the gravitational and electrostatic forces acting between two protons in the nucleus of an atom.

F (× 10−34 N)

Gravitational force

0 −1 −2 −3 −4 −5 −6 −7 −8

0

Nucleon distance d (× 10−15 m) 1 2 3

4

Electrostatic force 1000

F (N)

800 600 400 200 0

(e)

0

1 2 3 −15 Nucleon distance d (× 10 m)

4

(i)

If the distance between protons in a nucleus is 1.0 × 10−15 m, determine both the gravitational and the electrostatic force at this distance.

2

(ii)

Explain why these two forces cannot explain the stability of the nucleus, and why there is a need for the strong nuclear force.

2

(iii)

Describe TWO properties of the strong nuclear force.

2

Describe the requirements for a nuclear fission explosion, and describe how these are controlled in a nuclear reactor.

End of Question 31

– 40 –

8

Marks Question 32 — The Age of Silicon (25 marks) (i)

Identify ONE electronic system that is digital, and ONE electronic system that is analogue.

1

(ii)

Use diagrams to describe the variation between digital and analogue voltage outputs with time.

2

Construct a truth table showing the outputs at P, Q and R for each of the possible input states of A and B in the following circuit.

3

(a)

(b)

Gate 3 A

Gate 1

Gate 2

R

P Q

B

The graph below shows how the density of transistors on a silicon chip has increased over the last 30 years. 108 Transistor density (cm−2)

(c)

Gate 1 Inverter Gate 2 OR Gate 3 AND

107 106 105 104 103 1970

1980

1990 Year

2000

2010

(i)

Use the data in the graph to predict the change in computer performance from 1970 to 2005. Justify your answer.

3

(ii)

Discuss the validity of using the graph to predict computer performance up to 2060.

2

Question 32 continues on page 42

– 41 –

Marks Question 32 (continued) (d)

The circuit below uses a thermistor as a temperature sensor to control the operation of a relay. The relay will close when the voltage across the relay coil is greater than 6 volts. The resistance of the thermistor, RTHERM , is given in the graph. +12 V R 22 kΩ 100 kΩ −

A

+

Thermistor

Relay coil

3.0

RTHERM (kΩ)

2.5 2.0 1.5 1.0 0

5

10

15

20

25

Temperature (°C)

(e)

(i)

Calculate the voltage at point A at a temperature of 15°C. Neglect the effect of the 100 kΩ resistor and the operational amplifier on the voltage at point A.

3

(ii)

Determine the value of R so that the relay will close only when the temperature falls below 15°C.

3

Describe and compare the physical principles underlying the operation of input and output transducers. Use an analogue ammeter and a solar cell as examples.

8

End of paper – 42 –

BLANK PAGE

– 43 –

BLANK PAGE

– 44 – © Board of Studies NSW 2003

2003 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics DATA SHEET Charge on electron, qe

–1.602 × 10–19 C

Mass of electron, me

9.109 × 10–31 kg

Mass of neutron, mn

1.675 × 10–27 kg

Mass of proton, mp

1.673 × 10–27 kg

Speed of sound in air

340 m s–1

Earth’s gravitational acceleration, g

9.8 m s–2

Speed of light, c

3.00 × 108 m s–1

µ Magnetic force constant,  k ≡ 0  2π  

2.0 × 10–7 N A–2

Universal gravitational constant, G

6.67 × 10–11 N m2 kg–2

Mass of Earth

6.0 × 1024 kg

Planck constant, h

6.626 × 10–34 J s

Rydberg constant, R (hydrogen)

1.097 × 107 m–1

Atomic mass unit, u

1.661 × 10–27 kg 931.5 MeV/ c 2

439

1 eV

1.602 × 10–19 J

Density of water, ρ

1.00 × 103 kg m–3

Specific heat capacity of water

4.18 × 103 J kg–1 K–1

– 45 –

FORMULAE SHEET v = fλ I

m1 m2 r

Ep = − G

1

∝

F = mg

d2

v1 sin i = v2 sin r

v x 2 = ux 2 v = u + at

E =

F q

v y 2 = uy 2 + 2 ay ∆ y

R =

V I

∆ x = ux t

P = VI

1 2

∆ y = uy t + ay t 2

Energy = VIt

r3 T

vav =

aav

∆r ∆t

2

=

F =

∆v v−u therefore aav = = ∆t t

GM 4π 2

Gm1 m2 d2

E = mc 2

Σ F = ma F = Ek =

v2

lv = l0 1 −

mv 2 r

tv =

1 2 mv 2

t0 1−

W = Fs mv =

p = mv

v2 c2

m0 1−

Impulse = Ft

– 46 –

c2

v2 c2

FORMULAE SHEET F l

I1 I2

= k

1 p

d =

d

F = BIl sin θ

d M = m − 5 log    10 

τ = Fd IA IB

τ = nBIA cosθ Vp Vs

=

(mB − mA )

m1 + m2 =

np

4π 2 r 3

 1 1 1 = R 2 − 2  λ  n f ni 

V d

λ =

h mv

E = hf c = fλ

A0 = Vout

Z = ρv

Vin Ir I0

GT 2

ns

F = qvB sin θ E =

= 100

2 Z2 − Z1 ] [ = [ Z2 + Z1 ] 2

– 47 –

Vout Vin = −

Rf Ri

5

– 48 –

Yttrium

57–71

Strontium

56 Ba 137.3

Barium

88 Ra [226.0]

Radium

Rubidium

55 Cs 132.9

Caesium

87 Fr [223.0]

Francium

Rutherfordium

104 Rf [261.1]

Hafnium

72 Hf 178.5

Zirconium

90 Th 232.0

Thorium

Actinides 89 Ac [227.0]

Actinium

Protactinium

91 Pa 231.0

Praseodymium

59 Pr 140.9

Dubnium

105 Db [262.1]

Tantalum

73 Ta 180.9

Niobium

41 Nb 92.91

Vanadium

Uranium

92 U 238.0

Neodymium

60 Nd 144.2

Seaborgium

106 Sg [263.1]

Tungsten

74 W 183.8

Molybdenum

42 Mo 95.94

Chromium

Neptunium

93 Np [237.0]

Promethium

61 Pm [146.9]

Bohrium

107 Bh [264.1]

Rhenium

75 Re 186.2

Technetium

43 Tc [98.91]

Manganese

Plutonium

94 Pu [239.1]

Samarium

Americium

95 Am [241.1]

Europium

Curium

96 Cm [244.1]

Gadolinium

64 Gd 157.3

Ununnilium

Meitnerium

Hassium

63 Eu 152.0

110 Uun —

109 Mt [268]

62 Sm 150.4

Platinum

Iridium

78 Pt 195.1

Palladium

46 Pd 106.4

Nickel

108 Hs [265.1]

77 Ir 192.2

Rhodium

45 Rh 102.9

Cobalt

28 Ni 58.69

Osmium

76 Os 190.2

Ruthenium

44 Ru 101.1

Iron

27 Co 58.93

Berkelium

97 Bk [249.1]

Terbium

65 Tb 158.9

Unununium

111 Uuu —

Gold

79 Au 197.0

Silver

47 Ag 107.9

Copper

Californium

98 Cf [252.1]

Dysprosium

66 Dy 162.5

Ununbium

112 Uub —

Mercury

80 Hg 200.6

Cadmium

48 Cd 112.4

Zinc

30 Zn 65.39

Einsteinium

99 Es [252.1]

Holmium

67 Ho 164.9

113

Thallium

81 Tl 204.4

Indium

49 In 114.8

Gallium

31 Ga 69.72

Fermium

100 Fm [257.1]

Erbium

68 Er 167.3

Ununquadium

114 Uuq —

Lead

82 Pb 207.2

Tin

50 Sn 118.7

Germanium

32 Ge 72.61

Silicon

14 Si 28.09

Carbon

6 C 12.01

Sulfur

Phosphorus

Mendelevium

101 Md [258.1]

Thulium

69 Tm 168.9

115

Bismuth

83 Bi 209.0

Antimony

51 Sb 121.8

Arsenic

Nobelium

102 No [259.1]

Ytterbium

70 Yb 173.0

Ununhexium

116 Uuh —

Polonium

84 Po [210.0]

Tellurium

52 Te 127.6

Selenium

34 Se 78.96

16 S 32.07

15 P 30.97 33 As 74.92

Fluorine

Oxygen

Nitrogen

Lawrencium

103 Lr [262.1]

Lutetium

71 Lu 175.0

117

Astatine

85 At [210.0]

Iodine

53 I 126.9

Bromine

35 Br 79.90

Chlorine

17 Cl 35.45

9 F 19.00

8 O 16.00

7 N 14.01

Where the atomic weight is not known, the relative atomic mass of the most common radioactive isotope is shown in brackets. The atomic weights of Np and Tc are given for the isotopes 237Np and 99Tc.

Cerium

Lanthanum

Lanthanides 57 58 La Ce 138.9 140.1

Actinides

89–103

Lanthanides

39 Y 88.91

38 Sr 87.62

40 Zr 91.22

Titanium

Scandium

Calcium

26 Fe 55.85

29 Cu 63.55

37 Rb 85.47

25 Mn 54.94

Potassium

24 Cr 52.00

Aluminium

23 V 50.94

20 Ca 40.08

19 K 39.10

22 Ti 47.87

Magnesium

Sodium

21 Sc 44.96

13 Al 26.98

Boron

12 Mg 24.31

Name of element

11 Na 22.99

Atomic Weight Gold

Beryllium

Lithium

Symbol of element

5 B 10.81

79 Au 197.0

4 Be 9.012

3 Li 6.941 Atomic Number

KEY

PERIODIC TABLE OF THE ELEMENTS

Hydrogen

1 H 1.008

Ununoctium

118 Uuo —

Radon

86 Rn [222.0]

Xenon

54 Xe 131.3

Krypton

36 Kr 83.80

Argon

18 Ar 39.95

Neon

10 Ne 20.18

Helium

2 He 4.003

2004 H I G H E R S C H O O L C E R T I F I C AT E E X A M I N AT I O N

Physics

Total marks – 100 General Instructions • Reading time – 5 minutes • Working time – 3 hours • Write using black or blue pen • Draw diagrams using pencil • Board-approved calculators may be used • A data sheet, formulae sheets and Periodic Table are provided at the back of this paper • Write your Centre Number and Student Number at the top of pages 13, 17, 21 and 23

Section I

Pages 2–26

75 marks This section has two parts, Part A and Part B Part A – 15 marks • Attempt Questions 1–15 • Allow about 30 minutes for this part Part B – 60 marks • Attempt Questions 16–27 • Allow about 1 hour and 45 minutes for this part Section II

Pages 27–38

25 marks • Attempt ONE question from Questions 28–32 • Allow about 45 minutes for this section 433

Section I 75 marks Part A – 15 marks Attempt Questions 1–15 Allow about 30 minutes for this part

Use the multiple-choice answer sheet. Select the alternative A, B, C or D that best answers the question. Fill in the response oval completely. Sample:

2+4=

(A) 2 A

(B) 6

(C) 8

B

C

(D) 9 D

If you think you have made a mistake, put a cross through the incorrect answer and fill in the new answer. A

B

C

D

If you change your mind and have crossed out what you consider to be the correct answer, then indicate the correct answer by writing the word correct and drawing an arrow as follows.

correct A

B

C

–2–

D

1

The picture shows a game of cricket. Neglect air resistance

P

Q

The picture shows two consecutive shots by the batsman. Both balls reach the same maximum height above the ground but ball Q travels twice as far as ball P. Which of the following is DIFFERENT for balls P and Q? (A) Time of flight (B)

Initial velocity

(C)

Gravitational force

(D) Gravitational acceleration

–3–

2

The diagram shows two planets X and Y of mass m and 4m respectively.

d

d

Planet X of mass m Planet Y of mass 4m At the distance d from the centre of planet Y the acceleration due to gravity is 4.0 m s−2. What is the acceleration due to gravity at distance d from the centre of planet X? (A) 1.0 m s−2 (B)

2.0 m s−2

(C)

2.8 m s−2

(D) 4.0 m s−2

3

A spaceship at a distance r metres from the centre of a star experiences a gravitational r force of x newtons. The spaceship moves a distance – towards the star. 2 What is the gravitational force acting on the spaceship when it is at this new location?

(B)

x – newtons 2 x newtons

(C)

2x newtons

(A)

(D) 4x newtons

–4–

4

An object of rest mass 8.0 kg moves at a speed of 0.6c relative to an observer. What is the observed mass of the object? (A) 6.4 kg (B)

10.0 kg

(C)

12.5 kg

(D) 13.4 kg

5

Two spaceships are both travelling at relativistic speeds. Spaceship Beta shines a light beam forward as shown.

Beta

Light beam

Alpha

What is the speed of the light beam according to an observer on spaceship Alpha? (A) The speed of the light beam is equal to c. (B)

The speed of the light beam is less than c.

(C)

The speed of the light beam is greater than c.

(D) More information is required about the relative speed of the spaceships.

–5–

6

A ball is dropped by a person sitting on a vehicle that is accelerating uniformly to the right, as shown by the arrow.

Ignore air resistance

Which of the following represents the path of the ball, shown at equal time intervals, observed from the frame of reference of the vehicle? (B)

(A)

Direction of travel of vehicle

Direction of travel of vehicle

(D)

(C) Direction of travel of vehicle

Direction of travel of vehicle

–6–

7

Why do some electrical appliances in the home need a transformer instead of operating directly from mains power? (A) They require a voltage lower than the mains voltage. (B)

They require a source of energy that is DC rather than AC.

(C)

They require an alternating current at a frequency other than 50 Hz.

(D) They consume less energy than a similar device without a transformer.

8

A transformer which has 60 turns in the primary coil is used to convert an input of 3 V into an output of 12 V. Which description best fits this transformer? Type of transformer

9

Number of turns in secondary coil

(A)

Step up

15

(B)

Step down

240

(C)

Step up

240

(D)

Step down

15

An electric DC motor consists of 500 turns of wire formed into a rectangular coil of dimensions 0.2 m × 0.1 m. The coil is in a magnetic field of 1.0 × 10−3 T. A current of 4.0 A flows through the coil. What is the magnitude of the maximum torque, and the orientation of the plane of the coil relative to the magnetic field when this occurs? (A) 0.04 N m, parallel to the field (B)

0.04 N m, perpendicular to the field

(C)

0.4 N m, parallel to the field

(D) 0.4 N m, perpendicular to the field

–7–

10

A disc magnet has its poles on its opposing flat surfaces. An insulated copper wire was placed on the disc magnet as shown in the diagram. Y

X Disc magnet The instant the wire was connected to a DC battery, the wire was observed to move in the direction of the arrow. Which statement describes the direction of the magnet’s field and the direction of the current in the wire, consistent with this observation? (A) The field was vertically upward and the current was from X to Y. (B)

The field was vertically upward and the current was from Y to X.

(C)

The field was in the direction of the arrow and the current was from X to Y.

(D) The field was in the direction of the arrow and the current was from Y to X.

11

An electromagnet is attached to the bottom of a light train which is travelling from left to right, as shown. I v

When a large current is passed through the coils of the electromagnet, the train slows down as a direct result of the law of conservation of energy. In which of the following devices is the law of conservation of energy applied in the same way? (A) DC motor (B)

Loudspeaker

(C)

Induction motor

(D) Induction cooktop –8–

12

Photographs of two gas discharge tubes are shown.

What causes the variations of the pattern of striations in the gas discharge tubes? (A) Different gases in the tubes (B)

Different gas pressures in the tubes

(C)

Different voltages applied to the tubes

(D) Different electrode materials used in the tubes

–9–

13

Compared to silicon atoms, phosphorus atoms have one more electron in their outer shell. Boron atoms have one less electron than silicon atoms in their outer shell. Which of the following is the correct statement? (A) An n-type semiconductor is produced when silicon is doped with phosphorus, and a p-type semiconductor when silicon is doped with boron. (B)

A p-type semiconductor is produced when silicon is doped with phosphorus, and an n-type semiconductor when silicon is doped with boron.

(C)

The addition of phosphorus atoms turns silicon into a conductor but the addition of boron atoms turns silicon into an insulator.

(D) The addition of boron atoms turns silicon into a conductor but the addition of phosphorus atoms turns silicon into an insulator.

14

The minimum amount of energy needed to eject an electron from a clean aluminium surface is 6.72 × 10–19 J. What is the maximum wavelength of incident light that can be shone on this aluminium surface in order to eject electrons? (A) 9.86 × 10−16 m (B)

2.96 × 10−7 m

(C)

3.38 × 106 m

(D) 1.02 × 1015 m

– 10 –

The graph shows the intensity–wavelength relationship of electromagnetic radiation emitted from a black body cavity. 1.0 0.8 Intensity

15

0.6 0.4 0.2 0.0 0

200

400

600

800

1000

1200

1400

Wavelength (nm) In 1900, Planck proposed a mathematical formula that predicted an intensity–wavelength relationship consistent with the experimental data. The success of this formula depended on which of the following hypotheses? (A) The intensity of light is dependent on the wavelength. (B)

Light is quantised, with the energy of light quanta depending on the frequency.

(C)

Light is a wave whose intensity is readily expressed using mathematical formulae.

(D) Light is quantised, with the energy of the light quanta depending on the size of the cavity from which it is emitted.

– 11 –

BLANK PAGE

– 12 – © Board of Studies NSW 2004

2004 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I (continued) Part B – 60 marks Attempt Questions 16–27 Allow about 1 hour and 45 minutes for this part

Student Number

Answer the questions in the spaces provided. Show all relevant working in questions involving calculations.

Marks Question 16 (4 marks) A projectile is fired at a velocity of 50 m s–1 at an angle of 30° to the horizontal. Determine the range of the projectile. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

434

– 13 –

4

Marks Question 17 (6 marks) In July 1969 the Apollo 11 Command Module with Michael Collins on board orbited the Moon waiting for the Ascent Module to return from the Moon’s surface. The mass of the Command Module was 9.98 × 103 kg, its period was 119 minutes, and the radius of its orbit from the Moon’s centre was 1.85 × 106 metres. (a)

Assuming the Command Module was in circular orbit, calculate (i)

2

the mass of the Moon; ................................................................................................................... ................................................................................................................... ................................................................................................................... ................................................................................................................... ................................................................................................................... ...................................................................................................................

(ii)

the magnitude of the orbital velocity of the Command Module.

2

................................................................................................................... ................................................................................................................... ................................................................................................................... ................................................................................................................... ................................................................................................................... ................................................................................................................... (b)

The docking of the Ascent Module with the Command Module resulted in an increase in mass of the orbiting spacecraft. The spacecraft remained at the same altitude. This docking procedure made no difference to the orbital speed. Justify this statement. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... – 14 –

2

Marks Question 18 (4 marks) A car with a mass of 800 kg travels at a constant speed of 7.5 m s−1 on a roundabout so that it follows a circular path with a radius of 16 m.

Path that car follows

A person observing this situation makes the following statement. ‘There is no net force acting on the car because the speed is constant and the friction between the tyres and the road balances the centripetal force acting on the car.’ Assess this statement. Support your answer with an analysis of the horizontal forces acting on the car, using the numerical data provided above. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 15 –

4

Marks Question 19 (6 marks) On 11 June 2003 the Mars Rover called Spirit was launched on a satellite from Earth when the planets were in the positions shown in the diagram below. The satellite arrived at Mars on 3 December 2003.

Sun

Earth North pole Mars

(a)

Indicate on the diagram the approximate positions of Earth and Mars on 3 December 2003 and show the satellite’s trajectory to Mars.

3

(b)

Discuss the effect of Earth’s motion on the launch and trajectory to Mars of this satellite.

3

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 16 – © Board of Studies NSW 2004

2004 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 20 (2 marks) The photograph below shows a transmission line support tower. The inset shows details of the top section of the tower.

A A

B

B

Describe the role of each of the parts labelled A and B in the photograph. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

435

– 17 –

2

Marks Question 21 (6 marks) (a)

The diagram shows a two-pole DC motor as constructed by a student. Coils of copper wire (50 turns)

Pin

N

Bar magnet

Copper split-ring commutator

N Pin

Copper brushes touching the commutator

Identify THREE mistakes in the construction of this DC motor as shown in the diagram. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

Question 21 continues on page 19

– 18 –

3

Marks Question 21 (continued) (b)

An ammeter was used to measure the current through a small DC motor. While it was running freely, a current of 2.09 A was recorded. While the motor was running, the axle of the motor was held firmly, preventing it from rotating, and the current was then recorded as 2.54 A.

Explain this observation. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

End of Question 21

– 19 –

3

Marks Question 22 (3 marks) The photograph below shows parts of an AC electric motor.

Describe the main features of this type of motor and its operation. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 20 – © Board of Studies NSW 2004

3

2004 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 23 (6 marks) In the past 50 years electrical technology has developed from the widespread use of thermionic devices to the use of solid state devices and superconductors. (a)

List THREE disadvantages of thermionic devices that led to their replacement.

3

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Outline ONE advantage of using superconductors, with reference to TWO applications. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

436

– 21 –

3

Marks Question 24 (6 marks) In the late nineteenth century Westinghouse and Edison were in competition to supply electricity to cities. This competition led to Edison holding public demonstrations to promote his system of DC generation over Westinghouse’s system of AC generation. Propose arguments that Westinghouse could have used to convince authorities of the advantages of his AC system of generation and distribution of electrical energy over Edison’s DC supply. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 22 – © Board of Studies NSW 2004

6

2004 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 25 (6 marks) 6

An example of a solar cell is shown below. Direction of light Thin, transparent p-type layer n-type layer

The solar cell is able to produce a current due to the photoelectric effect and the electrical properties of the n-type and p-type layers. Use this information to outline the process by which light shining on the solar cell produces an electric current that can light up a light globe. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

437

– 23 –

Question 26 (7 marks) The diagram shows part of an experiment designed to measure the force between two parallel current-carrying conductors.

1

cm

.0 A

1 I1 =

I2 20

cm

The experimental results are tabulated below. I2 (A)

Force (× 10−6 N)

0

0

2.0

7

3.0

11

4.0

14

5.0

18

Question 26 continues on page 25

– 24 –

Marks Question 26 (continued) (a)

3

Plot the data and draw the line of best fit. 20 18 16

F (×10−6 N)

14 12 10 8 6 4 2 0 0

1.0

2.0

3.0

4.0

5.0

I2 (A) (b)

Calculate the gradient of the line of best fit from the graph.

1

.................................................................................................................................. .................................................................................................................................. (c)

Write an expression for the magnetic force constant k in terms of the gradient and other variables.

2

.................................................................................................................................. .................................................................................................................................. (d)

Use this expression and the gradient calculated in part (b) to determine the value of the magnetic force constant k. .................................................................................................................................. .................................................................................................................................. End of Question 26 – 25 –

1

Marks Question 27 (4 marks) A sports magazine commenting on the athletic ability of Michael Jordan, the famous basketball player said: ‘Being an athlete takes more brains than brawn. It takes time and effort. It takes endurance and commitment. It takes an athlete who can stay in the air for 2.5 seconds while shooting a goal; an athlete who knows which laws of physics keep him there.’ Assess the information presented in this magazine, using appropriate calculations to support your argument. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 26 – © Board of Studies NSW 2004

4

2004 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics Section II 25 marks Attempt ONE question from Questions 28–32 Allow about 45 minutes for this section Answer the question in a writing booklet. Extra writing booklets are available. Show all relevant working in questions involving calculations.

Pages

438

Question 28

Geophysics ........................................................................... 28–29

Question 29

Medical Physics ................................................................... 30–32

Question 30

Astrophysics ......................................................................... 33–34

Question 31

From Quanta to Quarks ....................................................... 35–36

Question 32

The Age of Silicon ............................................................... 37–38

– 27 –

Marks Question 28 — Geophysics (25 marks)

(a)

(i)

The magnetic properties of rocks (Earth materials) are useful in the study of geophysics.

1

Recall TWO other properties of Earth materials that are studied in geophysics.

(b)

(ii)

Describe the magnetic properties of Earth materials and outline how these properties have led to an understanding of the variation in Earth’s magnetic field over time.

3

(i)

The period of a simple pendulum can be used to calculate a value for g, using the relationship

4

T = 2π

l g

where l = length of the pendulum string in metres. An experiment was performed in which a pendulum 40.0 cm long had a period of 1.268 s. Use these data to calculate a value for g and hence calculate the radius of Earth at this location. (ii)

The pendulum was moved to a new location on the surface of Earth at the same latitude and same distance from the centre of Earth. At this new location the pendulum had a longer period.

2

Account for its longer period with reference to Earth’s gravitational field and propose a physical basis for this variation.

(c)

Explain the uses of satellites in providing information about Earth. Include in your answer a comparison of geostationary and low Earth orbits, proposing which would be preferred for remote sensing.

Question 28 continues on page 29

– 28 –

7

Marks Question 28 (continued) The diagram below summarises the changes of properties with depth in Earth. Density (tonnes/m3) Temperature °C 0 2 4 6 8 10 12 0 1000 2000 3000 4000

0

Seismic velocity (km/s) 2 4 6 8 10 12 14 0 100 200 300 400 500

P wave velocity

Depth (km)

1000 S wave velocity

(d)

2000

2895

5150

(i)

During your study of geophysics you carried out a first-hand investigation to analyse the variation in density of different rock types.

3

Describe how your investigation was carried out to ensure that the densities you determined were reliable. (ii)

Referring to the density graph above, account for the discontinuities (abrupt changes) at 50 km and 2895 km.

2

(iii)

The right-hand section of the diagram shows the velocity of P waves and S waves.

3

Account for the changes in velocity shown, including an explanation for the effects at 50 km and 2895 km for both P and S waves.

End of Question 28 – 29 –

Marks Question 29 — Medical Physics (25 marks) (a)

(i)

Describe how the piezoelectric material used in an ultrasound transducer can be made to vibrate to produce compressions and rarefactions in body tissues.

1

(ii)

Examine the following image showing the heads of unborn twins.

3

Describe how the image of the heads of the twins was produced. (b)

Different medical imaging technologies are used to enhance the information available to scientists and doctors. (i)

The following PET images of the brain show the active areas when the same words were seen on a video screen (left image) and heard through earphones (right image). To produce these images, glucose tagged with the radioisotope F-18 was first injected into the person’s body.

With reference to these images and the role of the tagged glucose, evaluate how PET imaging technology is changing our understanding of the way the brain functions. Question 29 continues on page 31 – 30 –

3

Marks Question 29 (continued) Identify the imaging technology used to obtain blood flow characteristics of blood moving through the heart, and describe the principle that enables information about the movement of blood to be measured.

3

Nobel Prizes are awarded annually ‘to those who . . . have conferred the greatest benefit to mankind’ (quote from Alfred Nobel’s will). The following table shows information about some people who have received Nobel Prizes, and the reasons for their award.

7

(ii)

(c)

Award

Recipients

Citation (reasons for award)

1956 Nobel Prize for Physics

William Bradford Shockley Walter Houser Brattain John Bardeen

‘for their researches on semiconductors and their discovery of the transistor effect’

1972 Nobel Prize for Physics

John Bardeen Leon Neil Cooper John Robert Schrieffer

‘for their jointly developed theory of superconductivity, usually called the BSC-theory’

2003 Nobel Prize for Physics

Alexei Abrikosov Vitaly Ginzburg Anthony Leggett

‘for their pioneering contributions to the theory of superconductors and superfluids’

2003 Prize for Medicine

Peter Mansfield Paul Lauterbur

‘for their discoveries concerning magnetic resonance imaging’

With reference to the physical processes upon which MRI depends, assess the impact of advances in knowledge about semiconductors and superconductors on the development of magnetic resonance imaging.

Question 29 continues on page 32

– 31 –

Marks Question 29 (continued) (d)

(i)

During your study of medical physics you carried out a first-hand investigation of the transfer of light by optical fibres. The diagram below shows part of the cross-section of an optical fibre, with the critical angle labelled.

2

Normal Cladding

P

Glass fibre

Ic

Sketch the diagram in your answer booklet and show a ray of light that is totally internally reflected at the point P in the fibre. (ii)

The photograph shows a normal endoscopic image of the transverse part of the large intestine.

3

www.gastrolab.net

Describe how the optical fibres in an endoscope are used to produce an image such as the one shown. (iii)

Describe how an endoscope could be used to obtain tissue samples from inside the large intestine, and outline why the endoscope is of particular use in this procedure.

End of Question 29

– 32 –

3

Marks Question 30 — Astrophysics (25 marks)

(a)

(b)

(i)

Identify the initial and final elements of the principal sequence of nuclear reactions for a star on the Main Sequence.

2

(ii)

Identify the type of star that the Sun will initially turn into after it completes its Main Sequence evolution. State the main source of energy in the core at this stage.

2

The apparent magnitudes of three stars are measured with a telescope equipped with a camera, first with a red filter placed in front of the detector, and then with a blue filter placed in front of it. The absolute magnitudes of the three stars can be determined from their spectra, and are listed in the fourth column of the table for the red filter. The results are shown in the table. Star

Absolute magnitude red filter

Betelgeuse

−0.89

+0.41

−6.47

Rigel

+0.18

+0.14

−6.69

Sirius

−1.46

−1.46

+1.46

(i) (ii)

(c)

Apparent magnitude Apparent magnitude red filter blue filter

Use the data in the table to determine which is the bluest of these three stars.

3

Calculate the distance to Rigel in parsecs.

3

Describe how the spectrum of a star can be used to determine its temperature, chemical composition and aspects of its motion.

Question 30 continues on page 34

– 33 –

7

Marks Question 30 (continued) An astronomer made regular measurements of the intensity of a star over the course of several days and obtained the light curve shown below. Light curve 101 100 99 Intensity

(d)

98 97 96 95 0

5

10 Time (days)

15

20

(i)

Describe the features of this light curve that suggest that the astronomer is observing an eclipsing binary system.

2

(ii)

If both stars have equal masses of 2 × 1030 kg, determine the separation of the two stars.

3

(iii)

The astronomer concludes that the system is a white dwarf eclipsing the other star. The intensity of light from the star is proportional to its cross-sectional area.

3

That is, I ∝ π r 2. Using the data and diagram, calculate the radius of the white dwarf as a fraction of the radius of the other star. Assume that the white dwarf has negligible luminosity.

End of Question 30

– 34 –

Marks Question 31 — From Quanta to Quarks (25 marks) (a)

(i)

Identify TWO features of the strong nuclear force that binds the nucleons together within the nucleus of an atom.

2

(ii)

When Chadwick discovered the neutron he estimated its mass as 1.15 times the mass of the proton, quite close to its true value.

2

State the TWO laws of physics he used to make this estimate.

(b)

(i)

The table below lists the first generation of quarks and antiquarks. Quarks Name

2

Antiquarks

Symbol

Charge

Up

u

+ 23 e

Down

d

− 13 e

Name

Symbol

Charge

Antiup

u

− 23 e

Antidown

d

+ 13 e

The Standard Model of matter states that baryons, like protons and neutrons, are comprised of three quarks, while mesons, like the pions π+ and π−, are comprised of one quark and one antiquark. Using the table above, state the quark composition of the neutron and the negative pion. (ii)

The first atomic bomb was a simple uranium-235 fission device. One mode of fission for uranium-235 is given below. 235 92U

+ 10n →

139 54Xe

+

94 38Sr

+ 3 10n

Calculate the mass defect and the energy released per the following nuclear masses and other data: 235 92U

= 234.9934 u

94 38Sr

= 93.8945 u

139 54Xe 1 0n

1 u = 1.66 × 10−27 kg

U atom, given

= 138.8883 u = 1.00867 u

c = 3.00 × 108 ms−1

u = atomic mass unit Question 31 continues on page 36

– 35 –

235

4

Marks Question 31 (continued) (c)

7 One cannot understand the [particle] physics of the past several decades without understanding the nature of the accelerator . . . the dominant tool in the field for the past forty years. By understanding the accelerator, one also learns much of the physics principles that physicists have laboured centuries to perfect. Leon Lederman and Dick Teresi, The God Particle, 1993

Describe how the key features and components of the standard model of matter have been developed using accelerators as a probe.

(d)

(i)

During your study of From Quanta to Quarks you carried out a first-hand investigation to observe the visible components of the hydrogen spectrum.

2

Identify the equipment you used to observe this spectrum. (ii)

During your physics course you examined first hand the emission spectrum of atomic hydrogen. The four coloured lines are listed in the table below. Name of the emission line

Electron transition

Red

Hα

n = 3 to n = 2

Green

Hβ

n = 4 to n = 2

Blue

Hγ

n = 5 to n = 2

Violet

Hδ

n = 6 to n = 2

Colour of the emission line

4

Calculate the wavelength of the Hβ spectral line, and hence determine the energy of the emitted photon. (iii)

Describe TWO limitations of Bohr’s model of the hydrogen atom.

End of Question 31

– 36 –

2

Marks Question 32 — The Age of Silicon (25 marks) (a)

(b)

(i)

Outline the role of the electromagnet and switch contacts in a relay.

2

(ii)

Explain how a relay works.

2

(i)

Identify the gate shown below and predict the output if the input at A is 1 and at B is 0.

2

A B (ii)

The diagram below shows a logic circuit. Determine the gate X which gives an output of 1 if the input A is 1 and B is 1. Justify your answer by using a truth table.

4

E A B

(c)

X C

Output

D

SILIAC, the first computer owned and operated by the University of Sydney, built in the 1950s, was constructed using thermionic devices. Its successor, the KDF9, was built in the late 1960s using solid state devices (transistors). Today’s supercomputers are built using integrated circuits. Assess the impact on computers of each succeeding device, with reference to the differences between each device.

Question 32 continues on page 38

– 37 –

7

Marks Question 32 (continued) (d)

The diagrams below show two different inverting amplifiers. 300 kΩ 10 kΩ

300 kΩ 15 kΩ

− +

Vin = 0.2 V

+

Vin = 0.1 V

Vout

Diagram 1 (i)

− Vout = –2 V

Diagram 2

Calculate Vout in Diagram 1.

2

The two circuits are now combined to produce a summing amplifier as shown below. 300 kΩ 10 kΩ −

15 kΩ V1 = 0.2 V

+

V2 = 0.1 V

Vout

Diagram 3 (ii)

Calculate Vout in Diagram 3 using your results in part (i) and the data in Diagram 2, and verify your value at Vout using the following formula for the output voltage for a summing amplifier.

3

V V  Vout = − R3  1 + 2  .  R1 R2  (iii)

Explain the use of the three resistors in the summing amplifier shown in Diagram 3.

End of paper

– 38 – © Board of Studies NSW 2004

3

2004 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics DATA SHEET Charge on electron, qe

–1.602 × 10–19 C

Mass of electron, me

9.109 × 10–31 kg

Mass of neutron, mn

1.675 × 10–27 kg

Mass of proton, mp

1.673 × 10–27 kg

Speed of sound in air

340 m s–1

Earth’s gravitational acceleration, g

9.8 m s–2

Speed of light, c

3.00 × 108 m s–1

µ Magnetic force constant,  k ≡ 0  2π  

2.0 × 10–7 N A–2

Universal gravitational constant, G

6.67 × 10–11 N m2 kg–2

Mass of Earth

6.0 × 1024 kg

Planck constant, h

6.626 × 10–34 J s

Rydberg constant, R (hydrogen)

1.097 × 107 m–1

Atomic mass unit, u

1.661 × 10–27 kg 931.5 MeV/ c 2

439

1 eV

1.602 × 10–19 J

Density of water, ρ

1.00 × 103 kg m–3

Specific heat capacity of water

4.18 × 103 J kg–1 K–1

– 39 –

FORMULAE SHEET v = fλ I

m1 m2 r

Ep = − G

1

∝

F = mg

d2

v1 sin i = v2 sin r

v x 2 = ux 2 v = u + at

E =

F q

v y 2 = uy 2 + 2 ay ∆ y

R =

V I

∆ x = ux t

P = VI

1 2

∆ y = uy t + ay t 2

Energy = VIt

r3 T

vav =

aav

∆r ∆t

2

=

F =

∆v v−u therefore aav = = ∆t t

GM 4π 2

Gm1 m2 d2

E = mc 2

Σ F = ma F = Ek =

v2

lv = l0 1 −

mv 2 r

tv =

1 2 mv 2

t0 1−

W = Fs mv =

p = mv

v2 c2

m0 1−

Impulse = Ft

– 40 –

c2

v2 c2

FORMULAE SHEET F l

I1 I2

= k

1 p

d =

d

F = BIl sin θ

d M = m − 5 log    10 

τ = Fd IA IB

τ = nBIA cosθ Vp Vs

=

(mB − mA )

m1 + m2 =

np

4π 2 r 3

 1 1 1 = R 2 − 2  λ  n f ni 

V d

λ =

h mv

E = hf c = fλ

A0 = Vout

Z = ρv

Vin Ir I0

GT 2

ns

F = qvB sin θ E =

= 100

2 Z2 − Z1 ] [ = [ Z2 + Z1 ] 2

– 41 –

Vout Vin = −

Rf Ri

5

– 42 –

Yttrium

57–71

Strontium

56 Ba 137.3

Barium

88 Ra [226.0]

Radium

Rubidium

55 Cs 132.9

Caesium

87 Fr [223.0]

Francium

Rutherfordium

104 Rf [261.1]

Hafnium

72 Hf 178.5

Zirconium

90 Th 232.0

Thorium

Actinides 89 Ac [227.0]

Actinium

Protactinium

91 Pa 231.0

Praseodymium

59 Pr 140.9

Dubnium

105 Db [262.1]

Tantalum

73 Ta 180.9

Niobium

41 Nb 92.91

Vanadium

Uranium

92 U 238.0

Neodymium

60 Nd 144.2

Seaborgium

106 Sg [263.1]

Tungsten

74 W 183.8

Molybdenum

42 Mo 95.94

Chromium

Neptunium

93 Np [237.0]

Promethium

61 Pm [146.9]

Bohrium

107 Bh [264.1]

Rhenium

75 Re 186.2

Technetium

43 Tc [98.91]

Manganese

Plutonium

94 Pu [239.1]

Samarium

Americium

95 Am [241.1]

Europium

Curium

96 Cm [244.1]

Gadolinium

64 Gd 157.3

Ununnilium

Meitnerium

Hassium

63 Eu 152.0

110 Uun —

109 Mt [268]

62 Sm 150.4

Platinum

Iridium

78 Pt 195.1

Palladium

46 Pd 106.4

Nickel

108 Hs [265.1]

77 Ir 192.2

Rhodium

45 Rh 102.9

Cobalt

28 Ni 58.69

Osmium

76 Os 190.2

Ruthenium

44 Ru 101.1

Iron

27 Co 58.93

Berkelium

97 Bk [249.1]

Terbium

65 Tb 158.9

Unununium

111 Uuu —

Gold

79 Au 197.0

Silver

47 Ag 107.9

Copper

Californium

98 Cf [252.1]

Dysprosium

66 Dy 162.5

Ununbium

112 Uub —

Mercury

80 Hg 200.6

Cadmium

48 Cd 112.4

Zinc

30 Zn 65.39

Einsteinium

99 Es [252.1]

Holmium

67 Ho 164.9

113

Thallium

81 Tl 204.4

Indium

49 In 114.8

Gallium

31 Ga 69.72

Fermium

100 Fm [257.1]

Erbium

68 Er 167.3

Ununquadium

114 Uuq —

Lead

82 Pb 207.2

Tin

50 Sn 118.7

Germanium

32 Ge 72.61

Silicon

14 Si 28.09

Carbon

6 C 12.01

Sulfur

Phosphorus

Mendelevium

101 Md [258.1]

Thulium

69 Tm 168.9

115

Bismuth

83 Bi 209.0

Antimony

51 Sb 121.8

Arsenic

Nobelium

102 No [259.1]

Ytterbium

70 Yb 173.0

Ununhexium

116 Uuh —

Polonium

84 Po [210.0]

Tellurium

52 Te 127.6

Selenium

34 Se 78.96

16 S 32.07

15 P 30.97 33 As 74.92

Fluorine

Oxygen

Nitrogen

Lawrencium

103 Lr [262.1]

Lutetium

71 Lu 175.0

117

Astatine

85 At [210.0]

Iodine

53 I 126.9

Bromine

35 Br 79.90

Chlorine

17 Cl 35.45

9 F 19.00

8 O 16.00

7 N 14.01

Where the atomic weight is not known, the relative atomic mass of the most common radioactive isotope is shown in brackets. The atomic weights of Np and Tc are given for the isotopes 237Np and 99Tc.

Cerium

Lanthanum

Lanthanides 57 58 La Ce 138.9 140.1

Actinides

89–103

Lanthanides

39 Y 88.91

38 Sr 87.62

40 Zr 91.22

Titanium

Scandium

Calcium

26 Fe 55.85

29 Cu 63.55

37 Rb 85.47

25 Mn 54.94

Potassium

24 Cr 52.00

Aluminium

23 V 50.94

20 Ca 40.08

19 K 39.10

22 Ti 47.87

Magnesium

Sodium

21 Sc 44.96

13 Al 26.98

Boron

12 Mg 24.31

Name of element

11 Na 22.99

Atomic Weight Gold

Beryllium

Lithium

Symbol of element

5 B 10.81

79 Au 197.0

4 Be 9.012

3 Li 6.941 Atomic Number

KEY

PERIODIC TABLE OF THE ELEMENTS

Hydrogen

1 H 1.008

Ununoctium

118 Uuo —

Radon

86 Rn [222.0]

Xenon

54 Xe 131.3

Krypton

36 Kr 83.80

Argon

18 Ar 39.95

Neon

10 Ne 20.18

Helium

2 He 4.003

2005 H I G H E R S C H O O L C E R T I F I C AT E E X A M I N AT I O N

Physics

Total marks – 100 General Instructions • Reading time – 5 minutes • Working time – 3 hours • Write using black or blue pen • Draw diagrams using pencil • Board-approved calculators may be used • A data sheet, formulae sheets and Periodic Table are provided at the back of this paper • Write your Centre Number and Student Number at the top of pages 13, 17, 21 and 25

Section I

Pages 2–27

75 marks This section has two parts, Part A and Part B Part A – 15 marks • Attempt Questions 1–15 • Allow about 30 minutes for this part Part B – 60 marks • Attempt Questions 16–27 • Allow about 1 hour and 45 minutes for this part Section II

Pages 29–43

25 marks • Attempt ONE question from Questions 28–32 • Allow about 45 minutes for this section 433

Section I 75 marks Part A – 15 marks Attempt Questions 1–15 Allow about 30 minutes for this part

Use the multiple-choice answer sheet. Select the alternative A, B, C or D that best answers the question. Fill in the response oval completely. Sample:

2+4=

(A) 2 A

(B) 6

(C) 8

B

C

(D) 9 D

If you think you have made a mistake, put a cross through the incorrect answer and fill in the new answer. A

B

C

D

If you change your mind and have crossed out what you consider to be the correct answer, then indicate the correct answer by writing the word correct and drawing an arrow as follows.

correct A

B

C

–2–

D

1

A ball thrown in the air traces a path as shown below.

Which of the following statements is true? (A) The velocity of the ball keeps changing. (B)

The acceleration of the ball keeps changing.

(C)

The velocity of the ball at the top of its motion is zero.

(D) The acceleration of the ball at the top of its motion is zero.

2

Why would a satellite in low orbit around Earth eventually fall to Earth? (A) It is not in a geostationary orbit. (B)

Gravity is too strong at low orbits.

(C)

The sun’s solar wind pushes it out of orbit.

(D) The upper atmosphere gradually slows it down.

3

The initial velocity required by a space probe to just escape the gravitational pull of a planet is called escape velocity. Which of the following quantities does NOT affect the magnitude of the escape velocity? (A) Mass of the planet (B)

Mass of the space probe

(C)

Radius of the planet

(D) Universal gravitational constant

–3–

4

A space probe, P, is in a stable orbit around a small, distant planet. The probe fires a forward-facing rocket that reduces its orbital speed by half. Which of the following best illustrates the subsequent motion of the probe? (A)

(C)

5

(B)

*P

(D)

*P

*P

*P

Napoleon attacked Moscow in 1812 with his cannon firing a shot at an elevation angle of 40°. Napoleon then decided to fire a second shot at the same speed but at an elevation angle of 50°. Which of the following observations would Napoleon expect to be true about the second shot when compared with the first? (A) Longer range (B)

Shorter range

(C)

Longer time of flight

(D) Shorter time of flight

–4–

6

In a particular experiment a long length of copper wire of very low resistance is rotated by two students. The ends of the wire are connected to a galvanometer, G, and a current is detected.

G Which of the following is LEAST likely to affect the amount of current produced? (A) The length of the rotating wire (B)

The thickness of the rotating wire

(C)

The speed with which the wire is rotated

(D) Whether the wire is oriented north-south or east-west

–5–

7

A single-turn coil of wire is placed in a uniform magnetic field B at right angles to the plane of the coil as shown in the diagrams. The coil is then rotated in a clockwise direction as shown. Which of the following shows the direction of current flow in the coil as it begins to rotate?

(A)

B

(B)

B

(C)

B

(D)

B

–6–

The primary coil of a transformer is connected to a battery, a resistor and a switch. The secondary coil is connected to a galvanometer.

V

G R

Which of the following graphs best shows the current flow in the galvanometer when the switch is closed?

Time

0

(C)

(D)

0

0

Time

–7–

Time

Current

0

Current

(B) Current

(A)

Current

8

Time

9

Three rings are dropped at the same time over identical magnets as shown below.

Plastic

Copper

Copper

N

N

N

S

S

S

P

Q

R

Which of the following describes the order in which the rings P, Q and R reach the bottom of the magnets? (A) They arrive in the order P, Q, R. (B)

They arrive in the order P, R, Q.

(C)

Rings P and R arrive simultaneously, followed by Q.

(D) Rings Q and R arrive simultaneously, followed by P.

–8–

10

A transformer is to be designed so that it is efficient, with heating by eddy currents minimised. The designer has some iron and insulating material available to build the transformer core. The windings are to be made with insulated copper wire. Which of the following designs minimises the energy losses in the core? (A)

Iron sheets

(B)

Iron

Insulated wire

Insulated wire

(C)

(D) Insulated wire

Insulating material

Insulating material

Iron rods Insulated wire

Insulating material

Iron sheets

11

The discharge tube shown below contains a rotating paddle wheel that is free to move. The tube’s electrodes are connected to a high-voltage source.

Cathode −

Cathode rays

Anode +

Which of the following statements about cathode rays does this apparatus provide evidence for? (A) Cathode rays travel in straight lines. (B)

Cathode rays are particles that have momentum.

(C)

Cathode rays can only be produced in vacuum tubes.

(D) Cathode rays are waves of high frequency and short wavelength.

–9–

12

The family of curves below shows the relationship between the intensity of black body radiation and its wavelength for various Kelvin temperatures.

8000 K

Intensity

5000 K

3000 K 0

1000

2000

3000

Wavelength (nm) This diagram has been adapted from Figure 2.18 in Physics Concepts and Applications, VCE Units 1&2 by Harding et al, Macmillan Education Australia, 1997. Reproduced by permission of Macmillan Education Australia.

Who was the first to correctly explain this relationship? (A) Planck, in 1900, when he suggested energy at the atomic level was quantised (B)

Einstein, in 1905, when he suggested light was a stream of particles called photons

(C)

Rutherford, in 1911, when he suggested the nuclear model of the atom

(D) Bohr, in 1913, when he suggested electrons exist in stationary states 13

A doped silicon semiconductor has the following energy-level diagram. Conduction band Dopant level Valence band What element was most likely used to dope the silicon? (A) Boron (B)

Germanium

(C)

Phosphorus

(D) Sulfur

– 10 –

14

An FM radio station transmits at a frequency of 102.8 MHz. What is the energy, in joules, of each photon emitted by the transmitter? (A) 6.446 × 10–42 (B)

6.812 × 10–26

(C)

2.918

(D) 3.084 × 1016 15

A current is passed along a square semiconductor rod as shown. Half of the current is carried by electrons and half by holes. A magnetic field is then applied to the rod at right angles to its axis.

Magnetic field

Conventional current Which of the following correctly describes the movement of the electrons and holes in the rod when the magnetic field is applied? (A) They speed up. (B)

They slow down.

(C)

They move to the same side of the rod.

(D) They move to opposite sides of the rod.

– 11 –

BLANK PAGE

– 12 – © Board of Studies NSW 2005

2005 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I (continued) Part B – 60 marks Attempt Questions 16–27 Allow about 1 hour and 45 minutes for this part

Student Number

Answer the questions in the spaces provided. Show all relevant working in questions involving calculations.

Marks Question 16 (5 marks) From nearest to furthest, the four satellite moons of Jupiter first observed by Galileo in the year 1610 are called Io, Europa, Ganymede and Callisto. For the first three moons, the orbital period T of each is exactly twice the period of the one orbiting immediately inside it. That is, TEuropa = 2 × TIo TGanymede = 2 × TEuropa The mass of Jupiter is 1.90 × 1027 kg, and the orbital radius of Io is 421 600 km. (a)

Use Kepler’s Law of Periods to calculate Ganymede’s orbital radius.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Calculate Ganymede’s orbital speed.

3

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... 434

– 13 –

Marks Question 17 (6 marks) Einstein’s 1905 theory of special relativity made several predictions that could not be verified for many years. (a)

State ONE such prediction.

1

............................................................................................................................... ............................................................................................................................... (b)

Describe an experiment to test this prediction.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (c)

Explain how technological advances since 1905 have made it possible to carry out this experiment. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 14 –

3

Marks Question 18 (4 marks) The idea of a universal aether was first proposed to explain the transmission of light through space. Michelson and Morley attempted to measure the speed of Earth through the aether. Evaluate the impact of the result of the Michelson and Morley experiment on scientific thinking. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

Please turn over

– 15 –

4

Marks Question 19 (4 marks) In 1970 NASA launched Apollo 13, their third mission planned to land humans on the Moon. Half-way to the Moon a huge explosion crippled the spacecraft. The only way home for the astronauts was to fly around the back of the Moon and then fire the rocket engine to take the craft out of lunar orbit and put it into an Earth-bound trajectory. At the completion of the rocket engine burn, mission leader Jim Lovell was heard to say, ‘We just put Isaac Newton in the driver’s seat’. Given that the spacecraft returned safely to Earth, justify Jim Lovell’s statement. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 16 – © Board of Studies NSW 2005

4

2005 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 20 (6 marks) In your course you had to gather information to explain how induction is used in certain applications. With reference to TWO applications, describe how you assessed the reliability of information you found. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

435

– 17 –

6

Marks Question 21 (6 marks) Two thin metal tubes one metre long were supported in a vertical wooden rack as shown in the diagram. tre

1 me

10 cm

−

+

The two ends were connected together, then the other two ends were connected briefly to a car battery as shown in the diagram. It was observed that one of the tubes jumped upward as the connection was made. (a)

Explain why only one tube jumped upward.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Each tube has a mass of 1 × 10−2 kg, and the tubes lie on the rack 10 cm apart.

3

What minimum current flows when one tube jumps? ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (c)

What is the implication of this result for power distribution networks? ............................................................................................................................... ...............................................................................................................................

– 18 –

1

Marks Question 22 (5 marks) A schematic diagram of a system to supply electricity to a house is shown below. High voltage transmission line Power plant

Step-down transformer Step-down transformer (substation)

Step-up transformer

11 000 V

240 V

J D Cutnell & K W Johnson, 2001, Physics, 5th edn. Reprinted with permission of John Wiley & Sons, Inc.

The step-down transformer in the substation has a turns ratio of 30 : 1. (a)

What is the voltage carried by the high voltage transmission line?

1

............................................................................................................................... ............................................................................................................................... (b)

Identify the causes of the two main energy losses in the transmission of electricity between the power plant and the house.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (c)

Explain how the application of superconductivity could minimise energy loss in the system. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 19 –

2

Marks Question 23 (3 marks) Explain how an understanding of black body radiation changed the direction of scientific thinking in the early twentieth century. ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

– 20 – © Board of Studies NSW 2005

3

2005 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Marks Question 24 (4 marks) Using labelled diagrams and text, explain how superconductivity occurs according to the BCS theory.

......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... ......................................................................................................................................... .........................................................................................................................................

436

– 21 –

4

Question 25 (6 marks) A student conducts an experiment using a photoelectric cell as shown in the diagram. Grid

Metal surface

Light enters Vacuum tube

100 V

µA

Light is shone through a grid onto a metal surface. The metal is at earth potential and the grid is at 100 V, so that any electrons emitted from the surface produce a current in the external circuit. The student shines light sources of different photon energies onto the metal surface and records the current flowing for each. The light sources are adjusted so that their intensities are equal. The results are recorded in the table and shown on the graph. Photon energy (eV)

Photo-current (µA)

0.50

0

0.90

0

1.20

0.5

1.70

2.8

1.75

4.0

1.90

8.0

2.20

9.2

2.50

9.4

Question 25 continues on page 23

– 22 –

Marks Question 25 (continued)

Photo-current (µA)

10

5

0

0.5

1.0

1.5

2.0

2.5

Photon energy (eV) (a)

On the grid provided, draw the straight line of best fit in the region where the photo-current varies greatest with photon energy.

1

(b)

From the line drawn on your graph, estimate the minimum energy (work function) for photoelectric emission.

1

............................................................................................................................... (c)

The experiment is repeated, but the intensities of the light sources are doubled. Predict the results of this new experiment by drawing a second line on the graph.

2

(d)

Justify the line you have drawn in part (c).

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... End of Question 25 – 23 –

Marks Question 26 (5 marks) The diagram shows two parallel horizontal metal plates connected to a DC source of electricity. Suspended between the plates is a charged particle of mass 9.6 × 10−6 kg.

−

−

−

Two metal plates separated by 2.0 cm

−

−

−

Charged particle +

+

+

+

+

49 V

+

(a)

Using conventional symbols, draw the electric field between the metal plates on the diagram above.

1

(b)

Determine the magnitude of the electric field between the plates.

1

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (c)

Determine the sign and magnitude of the charge on the particle if it is suspended motionless between the plates. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

– 24 – © Board of Studies NSW 2005

3

2005 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics

Centre Number

Section I – Part B (continued) Student Number

Question 27 (6 marks)

Please turn over

437

– 25 –

Question 27 (6 marks) Bubble chambers are used in conjunction with particle accelerators to photographically record the tracks of fast-moving charged particles. An intense magnetic field is applied at right angles to the path of the particles to deflect them according to their charge and momentum. The diagram shows a beam of protons travelling horizontally at 6.0 × 107 m s−1 and entering a liquid hydrogen bubble chamber in a vertical magnetic field of 1.82 T.

Camera

N

Powerful magnet

Proton beam

Liquid hydrogen bubble chamber

S

Examination of the photograph taken by the camera, as sketched below, shows that the protons were deflected along a circular path of radius 0.350 metres.

Proton beam

Proton tracks in bubble chamber

Question 27 continues on page 27

– 26 –

Marks Question 27 (continued) (a)

Derive an expression for the momentum of a proton from the forces it experiences in this experiment.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (b)

Calculate the mass of a proton in the bubble chamber.

2

............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... (c)

Calculate the rest mass of a proton found from this experiment. ............................................................................................................................... ............................................................................................................................... ............................................................................................................................... ...............................................................................................................................

End of Question 27

– 27 –

2

BLANK PAGE

– 28 – © Board of Studies NSW 2005

2005 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics Section II 25 marks Attempt ONE question from Questions 28–32 Allow about 45 minutes for this section Answer the question in a writing booklet. Extra writing booklets are available. Show all relevant working in questions involving calculations.

Pages

438

Question 28

Geophysics ........................................................................... 30–31

Question 29

Medical Physics ................................................................... 32–35

Question 30

Astrophysics ......................................................................... 36–38

Question 31

From Quanta to Quarks ....................................................... 39–41

Question 32

The Age of Silicon ............................................................... 42–43

– 29 –

Marks Question 28 — Geophysics (25 marks) (a)

(b)

During your study of geophysics you investigated the radiation reflected from various surfaces. (i)

Identify the equipment you used to obtain your results.

2

(ii)

Describe the use of reflected radiation in obtaining information about Earth from a distance.

2

On 6 December 2004 a meteor exploded in the atmosphere above northern NSW. The blast was detected by sensitive microphones in Hobart at 5.25 am (AEST) and in Tennant Creek at 6.12 am (AEST). AEST = Australian Eastern Standard Time

Awaiting Copyright Clearance

(i)

If Hobart is 1320 km from the explosion, how far is Tennant Creek from the explosion?

2

(ii)

Similar microphones have detected volcanic explosions such as the Mount St Helens (USA) volcanic explosion in 1980.

4

Identify another geophysical technique and explain how it is used to locate a volcanic explosion. Question 28 continues on page 31

– 30 –

Marks Question 28 (continued) (c)

The development of technologies that increased our understanding of Earth’s magnetic field led to the acceptance of the principle of plate tectonics.

7

Evaluate this statement. (d)

The diagram below shows the deflection of a plumb-bob near a large mountain range. The diagram exaggerates the amount of deflection.

Awaiting Copyright Clearance

(i)

Explain why the plumb-bob is deflected towards the mountain range.

2

(ii)

The observed deflection towards the mountain range is not as great as predicted due to the mountains alone.

3

What is the implication of this for plate tectonics? (iii)

Describe how Jean Richer used a pendulum to show that Earth is not spherical.

End of Question 28

– 31 –

3

Marks Question 29 — Medical Physics (25 marks) (a)

(i)

The images show a person’s heart before and after a medical procedure.

2

Awaiting Copyright Clearance

Abnormal heart before procedure

Heart after procedure

Describe how radioactive isotopes have been used to identify the abnormality and confirm its correction. (ii)

The table provides examples of some radioactive isotopes and their properties. Radioactive source

Radiation emitted

Half-life

11

Gamma

20.30 minutes

99

Gamma

6.02 hours

201

Gamma

3.05 days

131

Gamma

8.04 days

137

Alpha

30.17 years

238

Alpha

4.47 × 109 years

C Tc Tl I Cs U

Which radioactive isotope from the table would most likely be used to investigate the abnormality shown in the image above? Justify your choice.

Question 29 continues on page 33

– 32 –

2

Question 29 (continued)

(b)

(i)

The acoustic impedance of fat is 1.38 × 106 kg m−2 s−1. The acoustic impedance of bone is 7.80 × 106 kg m−2 s−1. What percentage of the incident intensity of an ultrasound wave is reflected as it crosses from fat into bone?

(ii)

(c)

Compare the physics involved in producing X-ray images with that used for endoscopies.

The images demonstrate advances in the use of ultrasound as a tool in medical diagnosis.

Awaiting Copyright Clearance

Describe advances in technology that have enabled the improvements shown in these images, and discuss current issues that have arisen from these advances.

Question 29 continues on page 34

Marks Question 29 (continued) (d)

(i)

The following diagram shows the constituent parts of an MRI system.

Awaiting Copyright Clearance

State the functions of the superconducting magnet assembly and the radio frequency (RF) coils in the MRI system. Question 29 continues on page 35

– 34 –

2

Marks Question 29 (continued) (ii)

The use of MRI may be improved by the introduction of gadolinium into the body. T1 curves for tissues A and B without gadolinium in the body

T1 curves for tissues A and B with gadolinium in the body

Awaiting Copyright Clearance

Explain why gadolinium has been introduced. (iii)

The arrow indicates an abnormality that has been detected in one hemisphere of the brain. MRI brain scan

Identify the advantages of MRI over a CAT scan in detecting this abnormality.

End of Question 29

– 35 –

2

Marks Question 30 — Astrophysics (25 marks)

(a)

Part A of the figure shows the absorption spectrum of light, produced by an incandescent filament, after it has been shone through a quantity of hydrogen gas. Also shown in the figure are the spectra obtained from two stars, Star Croesus in part B and Star Dromus in part C. The dark lines are absorption bands in A, B and C.

Spectrum Violet Blue Green

Source Red

(A)

Shone through hydrogen

Violet Blue Green

Red

(B)

Star Croesus

Violet Blue Green

Red

(C)

Star Dromus

DIAGRAMS NOT TO SCALE

(i)

For each star, Croesus and Dromus, identify the principal way in which its spectrum differs from the spectrum shown in part A of the figure.

2

(ii)

For each star, Croesus and Dromus, state what its spectrum tells us about the motion of that star.

2

Question 30 continues on page 37

– 36 –

Marks Question 30 (continued)

(b)

(i)

Photographs taken of a one arcsecond by one arcsecond sector of the night sky show a group of fixed stars. Scales have been added to the photographs. One star appears to change position, swinging backward and forward over a period of one year. Two photographic negatives taken when the star was at the furthest ends of its apparent travel are shown. The star is marked X.

2

1"

1" X

X 0

1"

0

1"

Calculate the distance of the star X from Earth.

(ii)

When viewed through a telescope, the star Alpha Centauri is seen to be three stars close together. Two of them are the very bright Alpha Centauri A and the very faint Proxima Centauri. These stars are 1.3 pc from Earth. Their magnitudes are given in the table below. Star

4

Absolute magnitude

Alpha Centauri A

+ 4.33

Proxima Centauri

+14.93

What is the ratio of their apparent brightnesses?

(c)

The Hertsprung–Russell (or H–R) diagram relates the magnitude or brightness of stars to their spectral classes or temperatures. Describe the technological advances that have made it possible to add astrophysical data to the H–R diagram, and explain how this data contributes to our understanding of stellar evolution.

Question 30 continues on page 38

– 37 –

7

Marks Question 30 (continued)

(i)

The graph shows the apparent magnitude of a supergiant star recorded over a period of time. The star is identified as a Type I Cepheid variable.

2

−3.0 Apparent magnitude

−3.5 −4.0

0

50

100 150 Time (days)

200

Explain how the period of oscillations in apparent magnitude may be used to determine the distance of the star.

The graph shows the brightness of a star system recorded over a period of time. The star system is identified as a binary pair, and measurements show them to be 5.0 × 1010 m apart. One star is known to have four times the mass of the other. Brightness

(d)

B

C A 0

5 Time (days)

10

(ii)

Explain what causes each of the features A, B and C labelled on the graph.

3

(iii)

Determine the mass of the star with the smaller mass.

3

End of Question 30

– 38 –

Marks Question 31 — From Quanta to Quarks (25 marks) (a)

During your study of From Quanta to Quarks you either performed a first-hand investigation, or you gathered information to observe nuclear radiation using a Wilson cloud chamber, or similar detection device. Below is a true-size photograph in this type of device showing the tracks made by α-particles.

Awaiting Copyright Clearance

(i)

Explain the appearance of these tracks in terms of properties of α-particles.

2

(ii)

Name another type of nuclear radiation, and describe differences in the tracks it would make.

2

Question 31 continues on page 40

– 39 –

Marks Question 31 (continued)

(b)

Naturally occurring uranium-238 spontaneously disintegrates according to the equation U → Th + α + γ. The thorium radionuclide undergoes further decay according to the equation Th → Q + β + –v + γ.

(c)

(i)

Identify the mass number of the thorium radionuclide.

1

(ii)

Identify the nuclide Q, stating its mass number.

2

(iii)

Describe Wolfgang Pauli’s contribution to Enrico Fermi’s explanation of beta decay.

3

An understanding of the nucleus led to the Manhattan Project, which was based in laboratories in Los Alamos between 1942 and 1945.

7

Describe the technologies developed from this project, and assess the significance to science and society of their applications.

Question 31 continues on page 41

– 40 –

Marks Question 31 (continued)

(d)

The diagram below shows the first five circular Bohr orbits or ‘stationary states’ for the electron orbiting the nucleus of the hydrogen atom. n=5

n=4 n=3 n=2 n=1

(i)

For the electron transition shown on the diagram, calculate the wavelength of the emitted photon.

2

(ii)

State de Broglie’s hypothesis, and calculate the wavelength of the electron in the first stationary state if its speed is 2.188 × 106 m s−1.

3

(iii)

Describe how de Broglie’s hypothesis extended the work of Bohr in explaining the stability of electron orbits in the hydrogen atom.

3

End of Question 31

– 41 –

Marks Question 32 — The Age of Silicon (25 marks)

(a)

(i)

2

Write down the truth table for the logical expression C = NOT (A AND B)

(ii)

(b)

Describe the function of a half-adder, and draw a circuit diagram to show how logic gates can be used in combination to make a half-adder.

2

An operational amplifier has the transfer characteristic shown. Vo (V) Vcc = +15 V 15

+ Vi

Vo

−

−7.5

Vi (µV)

7.5 −Vcc = −15 V −15

(i)

Design an amplifier with a gain of −50 using the above operational amplifier, and describe the difference between open-loop and closed-loop gain in your amplifier.

4

(ii)

In your writing booklet, sketch the output voltage of your amplifier as a function of time if the input voltage is a triangular wave as shown.

2

Input voltage 0.6 (volts) 0.5

1 1.5 Time (ms)

Question 32 continues on page 43

– 42 –

2

Marks Question 32 (continued)

(c)

Over the last ten years the ability to acquire, store and manipulate digital images has increased dramatically.

7

Describe the advances in semiconductor technology responsible for this increased ability, and explain how such changes have led to new consumer electronics applications.

(d)

(i)

Distinguish between input and output transducers, giving an example of each.

2

(ii)

The circuit below uses an optical isolator (comprising a LED and LDR) to electronically isolate a switch S from a digital gate G.

3

+10 V R

+5 V 10 kΩ S

G

Vi

200 Ω

When switch S is closed, a current of 20 mA flows through the LED and the voltage Vi is 1.6 V. Determine the resistance R. (iii)

The following table shows a variation of the resistance of the LDR as a function of LED current. LED current

LDR resistance

30 mA

190 Ω

20 mA

290 Ω

10 mA

600 Ω

1 mA

20 kΩ

< 0.1 mA

> 1 ΜΩ

Show, using calculations, how the digital output of the gate G, either ‘1’ or ‘0’, depends on whether the switch is open or closed. End of paper – 43 –

3

BLANK PAGE

– 44 – © Board of Studies NSW 2005

2005 HIGHER SCHOOL CERTIFIC ATE EXAMINATION

Physics DATA SHEET Charge on electron, qe

–1.602 × 10–19 C

Mass of electron, me

9.109 × 10–31 kg

Mass of neutron, mn

1.675 × 10–27 kg

Mass of proton, mp

1.673 × 10–27 kg

Speed of sound in air

340 m s–1

Earth’s gravitational acceleration, g

9.8 m s–2

Speed of light, c

3.00 × 108 m s–1

µ Magnetic force constant,  k ≡ 0  2π  

2.0 × 10–7 N A–2

Universal gravitational constant, G

6.67 × 10–11 N m2 kg–2

Mass of Earth

6.0 × 1024 kg

Planck constant, h

6.626 × 10–34 J s

Rydberg constant, R (hydrogen)

1.097 × 107 m–1

Atomic mass unit, u

1.661 × 10–27 kg 931.5 MeV/ c 2

439

1 eV

1.602 × 10–19 J

Density of water, ρ

1.00 × 103 kg m–3

Specific heat capacity of water

4.18 × 103 J kg–1 K–1

– 45 –

FORMULAE SHEET v = fλ I

m1 m2 r

Ep = − G

1

∝

F = mg

d2

v1 sin i = v2 sin r

v x 2 = ux 2 v = u + at

E =

F q

v y 2 = uy 2 + 2 ay ∆ y

R =

V I

∆ x = ux t

P = VI

1 2

∆ y = uy t + ay t 2

Energy = VIt

r3 T

vav =

aav

∆r ∆t

2

=

F =

∆v v−u therefore aav = = ∆t t

GM 4π 2

Gm1 m2 d2

E = mc 2

Σ F = ma F = Ek =

v2

lv = l0 1 −

mv 2 r

tv =

1 2 mv 2

t0 1−

W = Fs mv =

p = mv

v2 c2

m0 1−

Impulse = Ft

– 46 –

c2

v2 c2

FORMULAE SHEET F l

I1 I2

= k

1 p

d =

d

F = BIl sin θ

d M = m − 5 log    10 

τ = Fd IA IB

τ = nBIA cosθ Vp Vs

=

(mB − mA )

m1 + m2 =

np

4π 2 r 3

 1 1 1 = R 2 − 2  λ  n f ni 

V d

λ =

h mv

E = hf c = fλ

A0 = Vout

Z = ρv

Vin Ir I0

GT 2

ns

F = qvB sin θ E =

= 100

2 Z2 − Z1 ] [ = [ Z2 + Z1 ] 2

– 47 –

Vout Vin = −

Rf Ri

5

– 48 –

Yttrium

57–71

Strontium

56 Ba 137.3

Barium

88 Ra [226.0]

Radium

Rubidium

55 Cs 132.9

Caesium

87 Fr [223.0]

Francium

Rutherfordium

104 Rf [261.1]

Hafnium

72 Hf 178.5

Zirconium

90 Th 232.0

Thorium

Actinides 89 Ac [227.0]

Actinium

Protactinium

91 Pa 231.0

Praseodymium

59 Pr 140.9

Dubnium

105 Db [262.1]

Tantalum

73 Ta 180.9

Niobium

41 Nb 92.91

Vanadium

Uranium

92 U 238.0

Neodymium

60 Nd 144.2

Seaborgium

106 Sg [266.1]

Tungsten

74 W 183.8

Molybdenum

42 Mo 95.94

Chromium

Neptunium

93 Np [237.0]

Promethium

61 Pm [144.9]

Bohrium

107 Bh [264.1]

Rhenium

75 Re 186.2

Technetium

43 Tc [97.91]

Manganese

Plutonium

94 Pu [244.1]

Samarium

Americium

95 Am [243.1]

Europium

63 Eu 152.0

Meitnerium

Hassium

62 Sm 150.4

110 Ds [271]

109 Mt [268]

111 Rg [272]

Gold

79 Au 197.0

Silver

47 Ag 107.9

Copper

Curium

96 Cm [247.1]

Gadolinium

64 Gd 157.3

Berkelium

97 Bk [247.1]

Terbium

65 Tb 158.9

Darmstadtium Roentgenium

Platinum

Iridium

78 Pt 195.1

Palladium

46 Pd 106.4

Nickel

108 Hs [277]

77 Ir 192.2

Rhodium

45 Rh 102.9

Cobalt

28 Ni 58.69

Osmium

76 Os 190.2

Ruthenium

44 Ru 101.1

Iron

27 Co 58.93

Californium

98 Cf [251.1]

Dysprosium

66 Dy 162.5

Mercury

80 Hg 200.6

Cadmium

48 Cd 112.4

Zinc

30 Zn 65.41

Einsteinium

99 Es [252.1]

Holmium

67 Ho 164.9

Thallium

81 Tl 204.4

Indium

49 In 114.8

Gallium

31 Ga 69.72

Fermium

100 Fm [257.1]

Erbium

68 Er 167.3

Lead

82 Pb 207.2

Tin

50 Sn 118.7

Germanium

32 Ge 72.64

Silicon

14 Si 28.09

Carbon

6 C 12.01

Sulfur

Phosphorus

Mendelevium

101 Md [258.1]

Thulium

69 Tm 168.9

Bismuth

83 Bi 209.0

Antimony

51 Sb 121.8

Arsenic

Nobelium

102 No [259.1]

Ytterbium

70 Yb 173.0

Polonium

84 Po [209.0]

Tellurium

52 Te 127.6

Selenium

34 Se 78.96

16 S 32.07

15 P 30.97 33 As 74.92

Fluorine

Oxygen

Nitrogen

Lawrencium

103 Lr [262.1]

Lutetium

71 Lu 175.0

Astatine

85 At [210.0]

Iodine

53 I 126.9

Bromine

35 Br 79.90

Chlorine

17 Cl 35.45

9 F 19.00

8 O 16.00

7 N 14.01

Where the atomic weight is not known, the relative atomic mass of the most common radioactive isotope is shown in brackets. The atomic weights of Np and Tc are given for the isotopes 237Np and 99Tc.

Cerium

Lanthanum

Lanthanides 57 58 La Ce 138.9 140.1

Actinides

89–103

Lanthanides

39 Y 88.91

38 Sr 87.62

40 Zr 91.22

Titanium

Scandium

Calcium

26 Fe 55.85

29 Cu 63.55

37 Rb 85.47

25 Mn 54.94

Potassium

24 Cr 52.00

Aluminium

23 V 50.94

20 Ca 40.08

19 K 39.10

22 Ti 47.87

Magnesium

Sodium

21 Sc 44.96

13 Al 26.98

Boron

12 Mg 24.31

Name of element

11 Na 22.99

Atomic Weight Gold

Beryllium

Lithium

Symbol of element

5 B 10.81

79 Au 197.0

4 Be 9.012

3 Li 6.941 Atomic Number

KEY

PERIODIC TABLE OF THE ELEMENTS

Hydrogen

1 H 1.008

Radon

86 Rn [222.0]

Xenon

54 Xe 131.3

Krypton

36 Kr 83.80

Argon

18 Ar 39.95

Neon

10 Ne 20.18

Helium

2 He 4.003