STPM TRIAL PHYSICS 2

CONFIDENTIAL*/SULIT*

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960/2 *This question paper is CONFIDENTIAL until the examination is over.

[2 marks J

COJ\'FIDENTIAL *

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Section B [60 mark , where p and p are pressure and

density of the gas respectively and < c 2 > is mean square speed for the molecules in the gas. By comparing this equation with the equation PVm= RT, derive an equation of the average kinetic energy for one molecule for a monoatomic gas in terms of temperature T, gas constant Rand the Boltzmann constant k. [4 marks J (c) Calculate the total kinetic energy for a molecule of monoatomic gas at temperature 400 K.

[2 marksJ

(d) Sketch on the same axes two graphs to show the distribution of molecular speed for a gas at two different temperatures T1 and T2 where T2 > T1• Label the position of mean speed Vm, root mean square speed,

v

[3 marks]

and most probable speed V0 on each graph.

(e) Compare the two graphs and explain the physical characteristics of the two distributions by giving reasons for your answer. [2 marks]

12 (a) Two thin conducting plates have the same area of 0.50 m2 They are placed parallel to each other and 20 mm apart. One plate is maintained at +75 V while the other at- 75 V by a d. c. supply. (i)

Determine the amount of charge stored on each plate.

[3 marks]

(ii) Calculate the energy per unit volume stored in the electric field between the plates.

[2 marks]

(b) A parallel-plate capacitor of capacitance 3.0 JIF and a resistor of large resistance 1.0 MO are connected in series with a 12 V battery of negligible internal resistance.

(i)

Sketch graphs to show the time variation of the voltage across the capacitor and the current through it when switch Sis closed. Label clearly the maximum voltage and current on the respective graphs. [4 marks]

(ii)

What is the time constant of the circuit?

(iii)

Calculate the time taken for the capacitor to be 50% charged.

(iv)

With the switch S closed, the plates of the capacitor are pulled slightly apart. Describe the possible changes in the potential difference and the energy store in the capacitor. [3 marks]

960/2 *This question paper is CONFIDENTIAL until the examination is over.

[I mark] [2 marks]

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14

(a) The process X-rays production is the inverse of that of the photoelectric effect. Explain this statement. [2 marks]

(b)

The graph shows the X-rays spectrum produce by a X-ray tube.

Relative intensity

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Wavelength, ?. (i)

(ii) (iii) (c)

V.1hat is the effect of increasing the anode voltage to the characteristic X-rays and continuous X-rays spectra?

[2 marks]

What is the effect of using a metal target of higher atomic number?

[2 marks]

What is the effect of using a metal target of higher atomic number.

[2 marks]

An X-ray beam is incident on a solid sample. State two conditions that are necessary to observe X-ray diffraction peak from the sample. [2marks]

(d) A beam ofX-rays of wavelength 0.154 nm is incident on a crystal ofinterplanar spacing 0.288 nm. Calculate (i) the maximum order of diffracted X-rays beams that can be detected. (ii) the Bragg's angle for the highest order of diffraction. [5 marks]

14 (a) Define the binding energy per nucleon of a nucleus and mass defect of a reaction. (b) Calculate the binding energy per nucleon for (i) Uranium-23 8 nucleus, (ii) Carbon-12 nucleus.

[2 marks [3 marks] [3 marks]

Why is the Uranium-238 nucleus less stable than Carbon-12 nucleus?

[I mark]

(Given mass of neutron, m,=L00867 u; mass of proton, m,=L00782 u; atomic mass ofCarbon-12, Mc=l2.00000 u and atomic mass ofUranium-238, .i\10 =238.05079 u) (c) An element of unknown mass is mixed with '~C in a mass spectrometer. The radii of curvature of (the path of the ions) of the element and ions of '~C are 26.2 em and 22.4 em respectively. What is the element0 State any assumption made.

960/2 *This question paper is CONFIDENTIAL until the examination is over.

[6 marks]

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II

ERRATA

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. PEPERIKSAAN PERCUBAAN SETARA STPM NEGERI SEMBILAN DARUL KHUSUS TAHUN2011

DO NOT OPEN THIS LEAFLET UNTIL THE PHYSICS PAPER 2 EXAMINATION DAY

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This leaflet consists of 2 printed pages only. © Jabatan Pclajaran Negeri Sembilan 2011 STPM TRIAl. 960/2 *This paper is CONFIDENTIAL until the examination is over.

[Turn over COXFIDENTIAL*

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ERRATA on PAGE 14 Question 13 (b) (ii)

¥/hat is the effect of using a metal target of highe1 tttomie numbvr.

[2 marks]

(b)

(ii)

What is the effect of increasing the filament current to the continuous and characteristic X-ray spectra? [2 marks]

Question 14 (b)

Calculate the binding energy per nucleon for (i)

uranium-238 nucleus,

[3 marks]

(ii)

carbon 12 wl'iel-teeuttos