# SKEMA 7th Tips Physics SPM Success Modul Teknik Menjawab Kertas 2 Dan 3

August 26, 2017 | Author: Cikgu Faizal | Category: Refrigerator, Pressure, Inductor, Electric Current, Gases

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Tips perkongsian dari sumber Cikgu Mohd Ahir dan Cikgu Mazlena Guru Cemerlang SM Sains Kota Tinggi Johor http://...

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SKEMA JAWAPAN MODUL TEMBAK 32 VERSION 4 NO 1

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KNOWLEDGE Elasticity is the property of a substance which enables it to return to original shape @ size @ length after an applied external force ( compressive force or stretching force) is removed Electromagnet is a device in which magnetism is produced by an electric current // temporary magnet made by winding a coil round a soft iron core and magnetic field produce when current flow A phenomenon when light travel in different medium with different densities – change in speed and direction // the bending of light when travelling through different medium

MARKS 1

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Thermal equilibrium states that the net rate of heat flow from one medium to another medium and vice versa is zero// temperature for both medium is the same.

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Density/depth/acceleration due to gravity

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MENGKONSEPSI • Current flow in diagram 10.2 is more than 10.1 // vice versa. • The amount of iron filing attracted by iron core in Diagram 10.2 is more than 10.1 // vv. • The magnetic strength in diagram 10.2 is more than 10.1 // vice versa. • Amount of iron filing attracted increase when current increase • The magnetic field strength increase when current increase • The refractive index of A < the refractive index of B • The refracted angle of medium A > refracted angle of medium B • The density of medium A < density of medium B • The greater the refractive index the smaller the angle of refraction • The greater the refractive index the greater the ratio of sin i to • Diagram 10.1, the p end of diode is connected to negative terminal of dry cell // Diagram 10.2 the p end of diode is connected to positive terminal of dry cell • Bulb in Diagram 10.1 does not lights up • No current flow in Diagram 10.1 // Current flow in Diagram 10.2 • The bulb will lights up when the p end of diode is connected to the positive terminal of dry cell // vice versa • Current only flow in the circuit when p end of diode is connected to positive terminal of dry cell or in forward bias UNDERSTANDING • A soft ball has a high velocity. • A soft ball has a high momentum. • The soft ball player move his hand backward to increase time impact. • The higher the time impact will reduce impulsive force. • So we will not feel hurt. • the strong wind above the roof is moving very fast. • While the air in the house is at rest. • According Bernoulli's principle the higher the velocity the lower the pressure. • So, the pressure above the roof is smaller than pressure inside the house. • A force is generated by the difference in pressure which is

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• When the coil rotates the coil cut across the magnetic field lines • Induced current flow in the coil. • The current maximum when the coil cut the magnetic field at right angle // current decreased (become zero) when the coil move in parallel with magnetic field lines • The direction of current flow determine by using Fleming’s right hand rule • After 90o the direction of current in the external circuit reversed/ PROBLEM SOLVING QUALITATIVE ASPECT Bigger size of sail Supporting cable made by steel wire

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Low density Waterproof Hinged structure Structure from rigid Aspect

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Use oil High boiling point/low density Small Master piston Big slave piston Aluminium/steel for tansmision pipe

EXPLANATION Produce bigger different in pressure Easy to cut air resistance not easily break increase strength and rigidity Lighter Least upward lift is needed Not absorb water Glider can easily assemble and folded up for transportation. Lighter

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Explanation Incompressible/no air buble Does not evaporate easily/lighter To produce high pressure To produce a big force on the disc Strong/does not rust easily

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10 DESIGN Aerodynamic shape

EXPLANATION To reduce air resistance

Heat shield / material that is hard To protect the capsule to burn

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High melting point //ceramic

Do not melt

Landing in water // air bag

Increase time of impact// Reduce impulsive force

Light material / / small mass // low density

-Reduce the inertia // -reduce the momentum // -reduce impuls

Paracute / /Retro rocket

To reduce speed

Hard material // stiff composite

Not easy to bend

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APLICATION QUANTITATIVE -Atmospheric pressure at both side is equal -Pressure does not depends on size of arm Patm + h1ρy g = P atm + h2 ρx g

1 1 1

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( 10 x 10

-2

) ( 1 200 ) ( 10 ) = ( 16 x10 ρx = 750 kgm-3

-2

) ( ρx ) ( 10 )

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(b)(i) 12V (ii)

Eff

= Output Power x

10% Input Power Output Power = 24 x 2 = 48 W Input Power = VI =240 x 2 = 120 W = 48 X 100 120 = 40 %

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SOALAN MAKING DESISION characteristics Made of concrete low density

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thicker wall at the bottom // Diagram height from ground is high R is chosen

reason Stronger / Not easy to break // metal can rust easily lighter / the structure that hold the tank able to withstand the weight of tank able to withstand the higher pressure at the bottom to produce a greater difference in pressure Made of concrete, low density, thicker wall at the bottom, height from ground is high

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characteristics

reason

High specific heat capacity Heats up slowly / store more heat

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High boiling point

Slow to turn into vapour/volume of liquid decreases slowly

Big fan

Sucked a lot of air

A large number of fin blades

Increases surface area/releases heat faster.

Choose R

High specific heat capacity, High boiling point , Big fan, large number of fin blades

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Properties

Explanation

Low specific heat capacity

Easily to be hot

High melting point

Can sustain high temperature

Low density

lighter

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Low rate or rusty

So that it do not rust

S is chosen

Because of low specific heat capaity, high melting point, low density and low rate of rusty.

SOALAN STRUKTUR (a)(i)

(a) (ii) (b)

Soalan Menkonsepsi 1 Mass per volume Density of water > oil

Marks

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d1 > d2

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Pressure of water > oil // water > oil

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(c)

The higher the density the higher the pressure//As the density increases the pressure increases

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(d)

The deeper the water the higher the pressure The pressure in the tank > in the house (in the tap) The difference pressure produce force to flow the water

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(ii) (b)(iii)

TOTAL 7 (a) (b) (c) (i) (ii)

Soalan Modification 1 North pole 1 1. Increase the number of turns of coil 2. Increase magnitude of current / reduce resistance in the rheostat 1. Soft iron rod is attracted to the coils 2. Bar magnet pushed away 1. X becomes South pole and still attract the iron rod 2. Y becomes North pole / same pole as the bar magnet / force of repulsion

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(d) (i) (ii) (e) 8 (a) (b) (c)(i) (ii)

(iii) (d)

Iron rod is still attracted to the coil 1 Bar magnet will oscillate/ vibrate 1 Relay switch // electric bell etc 1 TOTAL Soalan Making Dicision 1 The power of device is the rate of which it transfers energy Electrical energy to light energy and heat energy Heat energy Filament bulb : - 11.25 x 100 % 75 = 15 % Energy saver bulb : - 10 x 100 % 20 =50 % Energy saver bulb High efficiency // less wasted energy Refrigerator or any other appliances Choose frost-free refrigerator // not allow frost to accumulate too thick in the freezer // close the door tightly TOTAL

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KERTAS 3 Questio n1 (a)(i)

Mar ks 1

(ii)

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(iii)

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Answer Stating the correct manipulated variable. Length of wire// l Stating the correct responding variable. Potential difference// Voltage// V Stating a correct fixed variable. Thickness of wire// resistivity of wire// type of wire

Tabulating results of the experiment (5 marks) 1. Labels l and V are shown 2. Correct unit for l and V 3. All readings of l are correct to one decimal place 4. Minimum 3 correct readings for V to 1 or 2 decimal place 5. All readings of V are correct to 1 decimal place Length,l / cm 20.0 40.0 60.0 80.0 100.0

Potentiakl diffr,V/V 0.4 0.9 1.2 1.6 1.9

or or or or or

0.40 0.90 1.20 1.60 1.90

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Plotting the l against V graph

(5 marks)

1 A. V on the y-axis and l on the x-axis. 2 B. Units stated for both l and V correctly 3 C. The scales on both axes are regular and not an odd scale. 4 D. 5 points plotted correctly from table(reading is wrong, plotting from table correct, mark can be given) 5 E. 3 points plotted correctly from table. 6 F. Line of best fit. 7 G. Graph size a minImum of 5×4 (5 boxes on y-axis, 4 boxes on x-axis).

(d)

(e) (i) (ii)

1 Stating the correct relationship V is directly proportional to l // V α l 1 Voltmeter reading decrease Resistance decrease 1

Questio n2 (a)(i) (ii)

Marks 1 1 1 1

Answer h is directly proportional to t2 // h α t2 1. Show on graph with appropriate vertical and/ or horizontal line corresponding to 44 cm 2. t2 = 0.088 3. t = (0.29 -0.30) s

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(b)

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(c) (i) (ii)

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(c)

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JUMLAH

1. Drawing the gradient triangle Triangle size a minimum of 8ver x 8 hor of cm 2. Substitution (values from student’s triangle) 3. Answer with correct unit 500 cms-2 u = 0 ms -1 1. Show that h = 1/2g t2 2. Substitution of the gradient ½ g = 500 3. Answer with correct unit. 1000 cms-2 or 10 ms-2 When measuring the values of h, make sure the eyes are perpendicular to the scale on the metre rule to avoid parallax error.

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Contoh Set 1 Questio n 1 a (i) (ii) (iii)

Marking Scheme Paper 3 Physics Mid Year SBP 2007 Mark Marking Scheme s 1 State the manipulated variable correctly ; The distance object 1 State the responding variable correctly ; The image distance 1 State one fixed variable; The focal length

b 1 1 1 1 1 1

1 1 and correctly in the table. u v 1 1 Shows a table which have u, v, and u v 1 1 State the correct unit of u/cm, v/cm, /cm-1 and u v /cm-1 All values of v are correct 1 Values of are correct u 1 Values of are correct v All values of are consistent

Tabulate ,u, v, A B C D E F

Object distance, u, (cm) 40 35 30 25 20

Image distance, v, (cm) 24.2 26.3 30.0 37.5 60.0

1 , u (cm-1) 0.025 0.029 0.033 0.040 0.050

1 , (cmv 1 ) 0.042 0.038 0.033 0.027 0.017

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Draw the graph of W against h. A - Label y-axis and x-axis correctly B - States the unit at the axis correctly C - Both axes with the even and uniform scale: D - 5 points correctly plotted: E - a smooth best straight line F - minimum size of the graph is 5 x 4 Squares of 2 x 2 cm:

(c)

Number of √ 6 5 3-4 2 1

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Score 5 4 3 2 1

State the correct relationship based on the candidate’s graph ( negative gradient striaght line graph) 1 1 decrease linearly to v u State ONE correct precaution so as to produce an accurate result of the experiment The position of the eye perpendicular when takes the reading to avoid errors due to parallax/systematic error 8

Total

16 Marks

SOALAN 1 –QUESTION 2 NO Marking Scheme

MARKS

2(a)

Show on the graph State the value of Patm correctly 1.06 x 105 Nm-2

2(b) (i)

Draw the triangle on the graph(minimum 8cm x 8cm) Show the substitution correctly Correct answer [1.30 x105 - 1.35 x105 ] Correct unit. Nm-3

2(b)(ii )

Correct answer [1560 - 1620 ]

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2(c)

Show on the graph State the value with the correct unit 1.6 x105 Nm-2

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2(d)(i )

State the changes correctly k will increase 2(d)(ii) 2(e)

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Give the correct explanation The pressure exerted by the liquid increases

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State the precaution correctly The position of Eyes is perpendicular to the scale of reading as to avoid parallax error // Repeate experiment twices and find the average to increase the accuracy

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Question 2 Section (a)(i) (ii) (iii) B (ii)

Marking scheme

Mark

V decreases linearly with I Extrapolate the graph 3.5 V Electromotive forcelle.m.f//d.g.e.

1 2 1

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Draw a sufficient large triangle (minimum size is 8 cm x 8 cm) * Correct substitution(follow candidate's triangle)

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(b)

I 1

(c)

I 1

(d)

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1.5 -3.5 1.2 -0 -1 State value unit A1.67 Show the v ertical/answer line fromwith 1 — 0,60 untilVA touch the graph then horizontal line until it touches he V-axis

V — 2.5 V E = I(R+r) 3.5 = 0.6(R +1.67 ) R=4.16 Ω

-Repeat the experiment and take average// -switch of the circuit when not taking any reading/! -Eye position must be perpendicular to scale of meter ruler

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total

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Section B (12 marks) Soalan 1 Inference : The size of the gas bubble depends on the depth of the water. Hypothesis: The smaller the pressure, the larger is the volume of a fixed mass of gas. Aim : To investigate the relationship between the pressure and volume for a fixed mass of gas at a constant temperature. Variables : Manipulated : Gas volume, V Responding : Gas pressure, P Fixed : Gas temperature,T or massof gas, m Apparatus : Glass syringe, a short rubber tube and Bourdon gauge Arrangement of apparatus: must label

Procedure: 1. The apparatus is set up as shown in the diagram above. 2. The piston of the syringe is adjusted until the volume of air in the syringe is 100 cm 3 at atmospheric pressure. 3. The syringe is connected to a Bourdon gauge and the pressure of the air in the syringe is observed and recorded. 4. The piston is then pushed in so that the volume of air trapped is 90 cm 3. The pressure is again recorded, this procedure is repeated for enclosed volumes of 80cm 3, 70 cm3 and 60 cm3. Tabulating data Volume, V/cm3 100 90 80 70 60

Pressure, P/Pa

Analysing data P/Pa

V/cm3

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Soalan 2/6 Inference: the strength of electromagnetism depends on the current in the coil. Hypothesis: The larger the current in the coil, the stronger the strength of electromagnetism Aim:To study the relationship between the size of current carried by the coil and the strength of electromagnetism. Variable: Manipulated variable: current, I Responding variable: strength of electromagnetism (number of pins collected) Fixed variable: no of turns Apparatus : pins, soft iron rod, insulated copper wire, connecting wires. Power supply, ammeter, rheostat , switch, retort stand with clamp. Arrangment of Apparatus

Procedure: 1.The switch is closed and the power supply is switched on . The rheostat is adjusted to obtain the current, I = 0.5 A. 2. The no of pins attracted to soft iron rod is counted. 3. The values of current I is repeated with I = 1.0A,1.5A, 2.0A and 2.5A Tabulating data Current,I/A 0.5 1.0 1.5 2.0 2.5

No pin attract,N N

I/A

Analysing data

Soalan 3/7 Inference: The buoyont force depent on the volume of an object Hypothesis: The higher the volume(or depth of iron bar/surface area) the higher the buoyant force

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Aim of experiment : To investigate the relationship between volume and buoyant force Variables in the experiment: Manipulated variable:Volume Responding variable:Reading of the spring balance(BF) Fixed/ constant variables:Volume of the water List of apparatus and materials: Measuring cylinder, a metal rod, spring balance and metre rule, beaker, water, retord stand Arrangement of apparatus

Procedure 1. The meter rule was clipped to the retort stand beside of the iron bar. 2. The volume of the iron bar is set at h = 20.0 cm 3 3. The reading of the spring balance is recorded. 4. Step 2 and 3 is repeated for the height, h= 25.0 cm, 30.0 cm, 35.0 cm and 40.0 cm. Tabulation of data Tabulating data Analysing data Volume,V/cm3 0.5 1.0 1.5 2.0 2.5

Weight, W/N

V/cm3

W/N

Soalan 8 (a) (b) (c) (i) (ii)

(iii)

Inference The distances between two consecutive bright fringes depends on the wavelength of light Hypothesis The higher the wavelength the higher the distance between two consecutives bright fringes Aim To investigate the relationship between the wavelength and the distances between two consecutives bright fringes. Variables a)manipulated : Wavelength of light/colour of light b)responding : distances between two consecutive bright fringes c)fixed : distance of slit, List of apparatus and materials Source of light, colour filter, screen, single slit, double slit and metre rule Arrangement of the apparatus

1 1 1 1 1 1 1

(iv) 12

(v)

Procedure of the experiment which include the method of controlling the manipulated variable and the method of measuring the responding variable. 1) A green (suppose value) filter is placed between the light source and the slits. The source of light is switched on. 2) The distance between two consecutive bright fringes is measured by using meter ruler 3) The experiment is repeated 5 times for with different colour filters ; red, yellow, blue and violet (state the value)

(vi)

Tabulate the data λ/cm x/cm

1 1 1

1

Analyse the data (vii)

x/cm 1

λ/cm TOTAL

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