trial stpm physics 2011_n9 (answ)

CONFIDENTIAL* /SULIT*

PEPERIKSAAN PERCUBAAN SETARA STPM NEGERI SEMBILAN DARUL KHUSUS

TAHUN 2011

DO NOT OPEN THIS BOOKLET UNTIL YOU ARE TOLD TO DO SO

Instructions to candidates: There are fifty questions in this paper. For each question, four suggested answers are given. Choose one correct answer and indicate it on the multi-choice answer sheet provided

Read the instructions on the multiple-choice answer sheet very carefully

Answer all questions. Marks will not be deducted for wrong answers.

A Data Booklet is provided

This question paper consists of 14 printed pages only. 1\";l Jabatan Pelajaran Negeri Sembilan 2011

STPM TRIAL 960/1 .,. This question paper is CONFIDENTL~ unti.l the examination is over.

[Turn over CONFIDEI'.l'IAL*

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STPM DATA BOOKLET For 960 PHYSICS - PAPER I AND PAPER 2

960 PHYSICS STPM

CONSTANT VALUES

************************************************************************

Speed of light in free space c = 3.00 x 108 ms-1

Permeability of free space flo 4n X 1 o-7 Hm-1

Permittivity of free space 0 8.85 x 10-12 Fm-1

Magnitude of electronic charge e 1.60 X 10-19 C

Plank constant h = 6.63 x 10-34 Js

Unified atomic mass constant U = 1.66 X 10-27 kg

Rest mass of electron me= 9.11 X 10-31 kg

Rest mass of proton mp = 1.67 X 10-27 kg

Molar gas constant R = 8.31 JK-1 mor1

Avogadro constant

Boltzmann constant k =us x 10-23 n(-1

Gravitational constant

Acceleration of free fall g = 9.81 ms-2

************************************************************************

STPM TRIAL 960/1 *This question paper is CONFIDENTIAL until the examination is over.

[Turn over CO NFID E!-.'TIAL *


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2

Which one of the following unit is derived unit?

A Candela B Mole c Second

v A liquid flowing horizontally through a pipe abides by the relation

v where is the rate of volume flow of the liquid

K is a dimensionless constant

pis difference in the liquid pressures at the two ends of the pipe

Lis the length of the pipe

R is the radius of the pipe

What is the dimension of If ?

A MLT 1 ll

D

KpR 4

((JL

D

Volt

3 The diagram below shows the path of a ball that was projected at an angle of 45' to the horizontal. By

ignoring the resistance of the air, the magnitude of change in momentum from the initial point 0 to the final

point Pis

0 p

A .fimu B 2mu c mu D mu 2

4 The maximum engine's power of the lorry of mass 2000 kg is 259 kW, the minimum time required by

the lorry to accelerate from rest to the speed of 45 ms-1 is

A 40.0 s B 25.5 s C 8.1 s D 7.8 s

5 An object of mass m moves with constant speed in a horizontal circle which

has radius, r as shown in the diagram shown. Determine the value of work done

and the change in momentum of the object when it moves from point A to B.

Work done Change in momentum

A Zero mv

22mv2 B zero

2!

c ,

zero mv~

D zero zero

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

v

A


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6 An external torque whose magnitude and direction are fixed acts on a rigid body hence causing the body

to rotate about a fixed axis, which one of the statements below is correct?

7

A The magnitude of the external force which produces the torque increases:~ ..

B The angular velocity of the body does not change when the body is exerted by the torque.

C The angular acceleration does not change when the body is acted on by the torque~

D The rotational kineti.c energy does not change when the body is acted on by the torque~

30~0 kg

20.0 kg

The above figure shows a system in equilibrium with the 30.0 kg block just about to slide along a horizontal

surface. What is the coefficient of static friction between the 30.0 kg block and the horizontal surface?

A 0.20 B 0.50 c 0.69 D 0.87

8

The diagram shows the position of two identical satellites at radius of R1 and R2 around the Earth. If U, K

and E represent the potential energy. the kinetic energy and the total energy of the satellites respectively.

Which one of the following statements states correctly the comparison of the three energies for satellite P

and S

A UP< Us 1 Kr>K, and E,

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9 A particle is moving such that the force F on it changes with the distance r from a fixed point as

shown. F

0 r

Which graph best shows the relationship between the potential energy E, of the particle and the distance r?

A B c D E, E,

r r r r

10 When damping is increased on an object undergoing resonant frequency oscillation, which change does

not occur?

A The amplitude of the driving oscillation decreases.

B The amplitude of the forced oscillation decreases.

C The resonant frequency decreases.

D The sharpness of the resonant peak decreases.

11 The diagram shows a long rope fixed at one end. The other end is moved up and down, setting up a

stationary wave.

vibration up and down

/ .-------.,_fixed

end

What is the phase difference between the oscillations at X and Y?

1 1 A 0 B ~ffrad C -1rrad

4 2 D

3 -rr rad 4

12 A sound wave is emitted from a point source. The intensity of the sound wave is inversely proportional

to the square of the distance from the source. At a distance r from the source, the amplitude of the wave is

8X. What is the amplitude at a distance 2r from the source?

A 8X B 4X C 2X D X

96011 *This question paper is CONFIDENTiAL until the examination is over. CONFIDENTIAL"


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13 A student blows across the top of a hollow bamboo pipe. The bottom of the pipe is closed

by a finger so that a fundamental tone of frequency .f is produced. Then the student blows again with the bottom of the pipe open. The tone that the student hears has a frequency

A equal to .f B lower than/ C higher than/ D fluctuating in the range off

14 The potential energy of a two-atom system is represented by a b

U = -, --;-, . The minimum value of U r- r -

represents

A the potential energy of the system when the atomic separation is a minimum.

B the potential energy of the system when the atomic separation is a maximum.

C the potential energy oftne system when the resultant force between the atoms is zero.

D the gravitational potential energy of the system when the atoms are at their lowest position.

15 Which of the following is the stress-strain graph for a glass rod which is stretched until broken?

Stress Slress Slf~SS ' / , . .,---"

,/ i

/1 /

0 I D i

Strain Straln 0'-----

A B c D 16 At what temperature is the r.m.s. speed of oxygen molecules the same as that of helium molecules at

300 K? [Relative molecular mass of oxygen= 32, relative molecular mass of helium= 4]

A 38 K B 849 K C 1440 K D 2400 K

17 The pressure p of an ideal gas is related to the mean square speed

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19 The ratio of principal molar heat capacities for air is 1.4. When air ofvolume'SOO cm3 at a temperature

of27'C is compressed adiabatically to a volume of I 00 cm3, its new temperature is

A 187 'C B 298 'C C 326 'C D 385 'C

20 One side of a room consists of a brick wall and a glass window. Both the brick wall and the glass

window have the same surface area. The thickness of the brick wall is 30 times that of the glass window,

I and the thermal conductivity of the brick is -that of the glass. The ratio of rate of heat flow through the

6 brick wall to that of the glass window is

A 5: I B 180: I c I : 5 D 1 :180

21 In an experiment to measure the thermal conductivity of a good conductor, a long test sample is used

so that

A the heat loss can be neglected

B the steady state is easily achieved

C the heat flow is parallel throughout the sample

D the temperature difference between the two ends of the sample is sufficiently large

22

2.0 m 2.0 m

A

The above figure shows three negative charges with charge -q or -2q are placed at the vertices A, B and C

of an equilateral triangle in free space. The length of each of the three sides is 2.0 m and Sis the idle point

of the side BC. What is the electric field strength at pointS?

A q

along AS B 2q

along AS 67r& 0 3m:,

c q along SA D 2q along SA 6nc o 3:rrc o

96011 *This question paper is CONFIDENTIJ\L until the examination is over. CONFIDENTIAL*


CONFIDENTJAL' g 23 The diagram below shows the electric field lines between two parallel metal plates, A and B.

..,.y 1 oo r --------r-----. .-----~---------

5. 0 em y

B z or

If )(Y = _!_ XZ, determine the work done in moving an electron from X toY ~

A c D

24 A certain capacitor consists of a pair of parallel metal plates separated by a distance d in the air. The

capacitor is charged then disconnected from the charging source and immersed in a liquid with permittivity

E. Which of the following statements regarding the capacitor is correct?

A Both the charge stored in the capacitor and its capacitance decreased.

B Both the charge stored in the capacitor and its capacitance increased.

C The capacitance of the capacitor increased but the potential difference across it decreased.

D The capacitance of the capacitor increased but the potential difference across it increased.

25 The circuit diagram shows a 10 kQ resistor and a 40 kQ resistor connected across a charged capacitor C.

,, ry;------,- i c s I

10 kQ

40 kQ

After switch S is closed. the potential difference V across the capacitor varies with timet. The graph of

In V against tis given as shown below.

In V

2

o'------~20~-.. t(s)

The capacitance of the capacitor is

A 1.2s x w' F B 2.00 X W 4 F c 1.2s x 1 o-' F D 2.50 X 10-3 F

96011 *This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*


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26 When a potential difference V is applied across the ends of a copper wire which has diameter d and

length /, the drift velocity of the electron is v. What is the drift velocity if the same potential difference is

applied across a copper wire ofhalfthe diameter but twice the length?.:

A v

B v c v D 2v

4 2

27 The resistance of a piece of pure silicon decreases rapidly with increasing temperature because

A the drift velocity of the charge carriers increases.

B the number of charge carriers increases

C the ratio of negative charge carriers to positive charge carriers increases

D the ratio of positive charge carriers to negative charge carriers increases

28 A battery of e.m.f. 2.0 V and negligible internal resistance is connected to four resistors as shown in

the diagram below.

--2.0 v -,-

'

What is the potential difference between the points P and Q ? A 0 V B 0.33 V C 0.67 V D 1.00 V

29 A milliammeter with negligible resistance gives a full scale deflection for 1 rnA. To convert it to a

voltmeter having a full scale deflection of 5 V,

A Connect a 5Q resistor in series with the milliammeter

B Connect a 50 Q resistor in parallel with the milliammeter

C Connect a 5 x 103 [l resistor in series with the milliammeter

D Connect a 5 Q resistor in series with the milliammeter and a 5 x 103 n resistor in parallel with the milliammeter

30 An electron and a proton both entering perpendicularly in the same magnetic field separately. If the

speed of the electron is I 0 times the speed of the proton. The ratio of the magnetic force on the electron to

the force on the proton is

A 1: I B I : 5 c 1 : 10 D 10:1

960!1 "This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*


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31 If the current through a long solenoid is doubled while the coil's length is also doubled, keeping the

total number of turns constant, the magnetic field at a middle point in the solenoid is .

A four times larger

B two times larger

C unchanged

D half the original size

32 When the speed of an electrical motor is increased due to a decreasing load, the current flowing

through it decreases. Which of the following is the best explanation of this phenomenon?

A The induced back e.m.f increases

B The resistance of the coil changes

C Frictional forces increased as the speed increases

D At high speeds it is more difficult to feed current into the motor

33 A circular flat coil of 200 turns of wire encloses an area of I 00 cm2

The coil is immersed in a uniform

perpendicular magnetic field Of 0.50 T that penetrate the entire area. If the field drops to zero in 200 ms,

what is the current induced in the coil if it has a resistance of 25 0?

A 0.20A B 0.50 A C l.OA D 5.0A

34 An alternating current 1 which flows through a 10 Q resistor is given b.Y 1= 3 sin lOOt. If I is in

amperes and tin _s.econck the mean power generated in the n:si

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36 The diagram shows a circuit of an inve1iing amplifier.

An input voltage of +2 V produces an output voltage of -8 V. Which statement about the circuit is not

true?

A

B c D

R,. The value of ~ IS 4.

R,

The voltage gain is- 4.

When the input voltage is -I V, the output voltage is+ 4 V.

When the input voltage is 2 V, the potential at point Pis 2 V.

37 If the input voltages V, and V2 in the circuit below are 50).lV and 90 J.N respectively, what is the

output voltage? [Gain~ I O']

+ 15 v

vt v2

-15 v

-'----"'if _______ __:!_ 0 v

A 40 J.!V B 4.0 V C +!5V D -15V

38 The propagation of an electromagnetic wave is accompanied by electric field oscillations and magnetic

field oscillations. Which of the following statements is no! true concerning the electromagnetic wave?

A The electromagnetic wave can be polarized.

B The electric field oscillations and the magnetic field oscillations are in phase.

C The directions of the electric field oscillation, the magnetic field oscillations, and the

electromagnetic field are perpendicular to one another.

D The oscillating frequency of the electric field and the oscillating frequency ofthe magnetic field

change when electromagnetic wave propagates from one medium to another medium.

960'1 *'This question paper is CONFIDE.'JTIJ\L until the examination is over. CONFIDENTIAL*


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39 The diagram below shows a long glass rod with uniform diameter 2r. . The left end of the rod has a

semicircular convex surface of radius r. The refractive index of the glass is n-. An object 0 is placed on

the left side and at the axis of the rod.

O>E---~ I I

I I I I I I I I I

~ u ---7:~--- v ----:::>~:

2r

If the image distance v produced in the rod is twice the object distance from the end of the rod, the object

distance u is

(n+2}r A 2n B

(1'1 +:2)r

2(n-( c 2 (n- t)1

c,~ + 2) D 2(1-n)r

(r:!+2)

40 A monochromatic light is directed towards a single adjustable slit to produce a diffraction pattern on

a screen as shown.

Intensity Central maximum

Subsidiary maxima

0

When the width of the slit is reduced,

A the intensity of the central peak will mcrease and the intensity of the subsidiary maxima will

decrease.

B the intensity of all maxima will increase and the width of the pattern will decrease.

C the intensity of all maxima do not change and the width of the pattern will increase.

D the intensity of all maxima will decrease and the width of the pattern will increase.

960!1 ~This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*


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41 The diagram below shows a light beam incident on the surface of glass which has been coated with an

optical materiaL

If the wavelength of light in the optical material is J. and the reflective index for the optical material and the

glass are n1 and n2 respectively, which of the following is the condition for the reflected light beams x andy

to experience destructive interference?

A

c ;{ t = - and n1 < n:2 2

B

D t = A and n 1 < n:!

42 Which of the following is true based on the photoelectric effect?

A The emission of electrons will not occur for very low light intensity.

B The number of electrons produced per second does not depend on the intensity of light.

C The maximum velocity of the electrons increases when the wavelength of light decreases.

D The average kinetic energy of the electrons decreases when the frequency of light increases

43 If electron A has twice the kinetic energy of electron B, the ratio of the de Broglie wavelength of

electron A to that of electron B is

A 1 : 2 B ] : \ ~ c 2. D

44 A hydrogen atom absorbs a photon and as a result an electron is excited from the ground state to the

second excited state. lfthe n,h energy level of the hydrogen atom is given by , =-13

;6

eV, the photon n-

energy absorbed is

A 3.4 eV B 10.2 eV C 13.6 eV D 12.1 eV

960/1 *This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*


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45 The property of the metal should be chosen as a target anode in an X-ray tube is

A a good conductor of electricity

B a good conductor of thermal energy

C a good insulator of thermal energy

D a good reflector of thermal energy

46 The mirror fixed at the end of the tube in a helium-neon laser system is used to

A improve the rate of production of electrons

B increase stimulated emission of photons

C absorbed part of the photons

D reduces the loss of laser light from the system

47 The mass of the nucleus 6~ I 1 ,;cu, the mass of nucleus 1 H and the mass of 0 n are 62.9296u,

1.00783u, and 1.00867u respectively. What is the binding energy per nucleon for the nucleus?

A 5.40 X 10-13 J B 1.28 X J0 -!2 J D 8.85 x 10-11 J

48 A radioactive isotope of an element X experiences a series of decays until it becomes a stable isotope

for element X. In the process, the ratio of number of a particles emitted against the number of j3 particles emitted is

A 2:2 B 2: 1 c 1:2 D 1 : 1

49 Helium nucleus is produced when a lithium nucleus is bombarded by a proton, as shown in the below

equation:

If the speed of light is c, mass of lithium is mL.rnass of proton is mp and mass of helium is mH, which of the

following expressions represents the energy released in this nuclear reaction?

A (mL + mp+2 mH) c'

' B (mL + mp- 2 mH) c C (mL + 2 mH- mr) c2

D (mL + 2 mH + rnp) c:;

50 Which one of the following is the main characteristic of a quark?

A Jt has zero rest mass

B lt travels at the speed of light

C lt has fractional charge

D lt is a combination of baryons



CONFIDENTIAL*/SULIT*

'T'u.rn hour~ on.rr +h; .... n, rni-nn+o.c rnua Jam t'g" pI .. ~l., -....,!,_! ... , rJJ{/, _.._ ,, ,_,. "'~ - "._,. ~~-'-''-'- ..,.._.._._.._ "'J .t.Ai..o.i..

STPM DATA BOOKLET For 960 PI-fYSICS - PAPER 1 AND PAPER 2

960 PHYSICS STPM

CONSTANT VALVES

************************************************************************ Speed of light in free space c =3.00x 108 ms- 1

Permeability of free space flo 4n X 1 o-7 Hm-1

Permittivity of free space &0 8 8 - 1 o-12 F -I . )X m

Magnitude of electronic charge e 1.60 X 10-19 C

Plank constant h = 6.63 x 10-34 Js

Unified atomic mass constant U = 1.66 X 10-27 kg

Rest mass of electron me= 9.11 X 10-31 kg

Rest mass of proton mp = 1.67 x 1 o-27 kg

Molar gas constant

Avogadro constant

Boltzmann constant k = 1.38 x 10.23 JK-1

Gravitational constant G = 6.67 X 1 o-Il Nnl kg-2

Acceleration of free fall g=9.81 ms-2

************************************************************************

STPM TRIAL 960/2 .,. This question paper is CONFIDENTIAL until the examination is over.

[Turn over CONFIDENTIAL*


CONFIDENTIAL* 3

Section A [ 40 marks]

Answer all questions in this section.

1 The heat capacity C of a substance is defined as "quantity of heat supplied to raise the temperature of a substance by 1 K. The heat capacity C of a solid is given by the expression

C=aT-bT 3

where T is the absolute temperature, a and b are constants with dimension.

(a) Determine the dimension of heat capacity, C. [I mark]

(b) Write down the Sl unit of heat capacity, C [1 mark]

(c) Find the units for a and b. [3 marks]



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2 The rotating blade of a blender turns from rest with a constant angular acceleration 1.50 rads-1 .

(a) How long does it take to reach an angular velocity of36.0rads-' 7 [2 marks]

(b) What is the number of revolutions in this time interval? [3 marks]



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3 The graph shows the variation of extension with force of a wire before reaching the elastic limit. The original length of the wire is 2.0 m and its cross section area is 0.50 mm2;

e (mm)

0.6

F[N)

(a) Calculate the work done to extend the wire to 1.20 mm. [2 marks]

(b) Calculate the Young's modulus of the wire. [3 marks]

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


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4 The graph shows the variation of pressure with volume for 0.128 mol of an ideal gas at temperatures 600 K and 850 K.

p (kPa)

w

80 T2 = 850 K

T, = 600 K oL-------~------------~

8.0

By using the graph, calculate (a) the volume of gas at Y, and

(b) the work done for the gas to change its state from W toY.

V(~ 10-3 rn 3)

[:2 marks]

[2 marks]

(c) If the gas at W experiences an adiabatic expansion to reach a temperature of 600 K, sketch the path to show the adiabatic expansion on the graph above. [1 mark]

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


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5 (a) A variable inductor is usually used to regulate the speed of an electric ceiling fan instead of a variable

resistor. Explain. [2 marks J

(b) A inductor with a inductance of0.20H is connected to a 12 V ac supply with a frequency of 50 Hz. Calculate

(i) the reactance of the inductor. [1 mark]

(ii) the nns current in the circuit. [2 marks]

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


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6 An air wedge is fonned by placing a wire between two pieces of glass plates as shown in the diagram below. The length of the glass plate is !Ocm. When monochromatic light of wavelength 475 nm is incident normally on the air wedge, interference pattern can be observed.

A===========cC}-wire glass plates ~L _____________ _j)

!Ocm

(a) Determine the diameter of the wire if380 dark fringes are observed in the interference pattern formed. [3 marks]

(b) If the wire is pushed in slightly to reduce the length of the air wedge, explain any changes to the fringe width. [2 marks J

960l2 *This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*


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7 (a) State two observations from experiment on photoelectric effect that cannot be explained by wave theory. [2 marks J

(b) A monochromatic light wavelength of 3 50 nm illuminates the surface of a potassium metal with work function of2.30 eV. Calculate the maximum speed of photoelectron emitted. [3 marks]



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8 (a) Explain what is meant by the halllife of a nuclide. [1 mark]

(b) A source with decay constant 6.4 x I o' 0 s' has an activity of 5. 7> 1 O' Bq.

Calculate, for this source,

(i) the half-life [2 marks]

(ii) the time taken for the activity to fall to 6.0>< J 05 Bq. [2 marks J

960/2 *This question paper is CONFIDENTIAL until the examination is over. COJ\'FIDENTIAL *


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Section B [ 60 mark

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10 (a) (i) Explain what is meant by the.fi-equency of vibration of an object. [l mark] (ii) Distinguish between the displacement of a vibrating object and the amplitude of vibration_

[2 marks] (b) Graph below shows the variation with displacement x of the acceleration a of a particle that attached

to the cone of a loudspeaker.

4000 ' -

aims 2

2000

1000

-(),6 OA 0,2 0

0 0,2 OA 0,6

xlmm

2000

3000

' -4000

(i) Use the figure to explain why the motion of the particle is simple harmonic. [2 marks]

(ii) Show that the frequency of oscillation of the particle is 464-Hz. [2 marks]

(c) The magnitude of the gradient ofthe line in the graph is G.

(i) Show that, for a particle of mass 111 oscillating with amplitude A, its maximum kinetic energy Ewax rs given by Em,.,= y, mGA2 . [3 marks]

(ii) Determine E.,w for the particle of mass 2.5 >>I o-J kg. [2 marks]

(d) (i) Explain what is meant by resonance.

(ii) A washing machine has a drum which can rotate at high speed. the base of the machine, helps to reduce the possibility ofresonance.

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

[2 marks]

Suggest why a concrete block, fixed at [1 mark]

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11 (a) In the kinetic theory of gasses, several assumptions are made concerning'an ideal gas. State four of the assumptions. [ 4 marks]

1 2 (b) The equation for the kinetic theory of gas is given by p = - p < c > , where p and p are pressure and

3 density of the gas respectively and < c2 > 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 marks J

(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 and most probable speed V0 on each graph. [3 marks]

(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.

960/2

(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? [I mark]

(iii) Calculate the time taken for the capacitor to be 50% charged. [2 marks]

(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]

*This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*


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

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

Relative intensity

I I I I I I I I I I I I

Wavelength, ?.

[2 marks]

(i) V.1hat is the effect of increasing the anode voltage to the characteristic X-rays and continuous X-rays spectra? [2 marks]

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

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

[2 marks]

[2 marks]

(c) 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.

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

(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)

[2 marks

[3 marks] [3 marks]

[I mark]

(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. [6 marks]



CONFIDENTIAL*/SULIT*

II ERRATA

. PEPERIKSAAN PERCUBAAN SETARA STPM NEGERI SEMBILAN DARUL KHUSUS

TAHUN2011

ll

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

A'' I I --l

STPM TRIAl. 960/2

This leaflet consists of 2 printed pages only. Jabatan Pclajaran Negeri Sembilan 2011

*This paper is CONFIDENTIAL until the examination is over. [Turn over

COXFIDENTIAL*

I


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,

(ii) carbon 12 wl'iel-teeuttos

ERRATA on PAGE 14

Question 13

(b)

(ii) 'Nbat is the effect of using a metal target ofhigherltlomie nmnbd. [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) CJranitun-23 8 nucleus,

(ii) carbon 12 ntteleus.

(b) Calculate the binding energy per nucleon for

(i) uranium-238 e:~u) nucleus,

(ii) carbon-12 ('~C) nucleus.

End

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

[3 marks]

[3 marks]

[3 marks]

[3 marks]

[Turn over CONFIDENTIAL*


CONFIDENTIAL*

JAWATANKUASA PANEL TRIAL EXAM PHYSICS STPM

NEGERI SEMBILAN DARUL KHUSUS

MARKING SCHEME FOR

JPHYSli

CONFIDENTIAL*

I. Which one ofthe following unit is derived unit?

A Candela B Mole C Second

-------------------------------------, I I 1 Answer: D '

. . Ulork Potential difference = -,-"---

charge

Energy

charge

E = V=-

Q I 1

'-------------------------------------~

v 2. A liquid flowing horizontally through a pipe abides by the relation

v where is the rate of volume flow of the liquid

t K is a dimensionless constant

pis difference in the liquid pressures at the two ends of the pipe L is the length of the pipe

R is the radius of the pipe

What is the dimension of cp ?

ANSWER:B

t

D Volt

KpR4 rpL -,

, [kpR'] (ML'T-2 )(L' )(T)

['Jl]~ VL ~ (L')(L) ~ ML-1T 1

3. The diagram below shows the path of a ball that was projected at an angle of 45 to the horizontal.

By ignoring the resistance of the air, the magnitude of change in momentum from the initial point 0

to the final point P is

u

0 p

A .fimu mu

D mu

2mu c 2

B



CONFIDENTIAL*

Solution: A

The horizontal change of momentum = 0

The vertical change of momentum

= mu sin45- (-mu sin45)

I I =mu-- (-mu-)

J2 J2

I =2mu-

J2

2

4. The maximum engine's power of the lorry of mass 2000 kg is 259 kW, the minimum time

required by the lorry to accelerate from rest to the speed of 45 ms- 1?

5.

A 40.0 s B 25.5 s c. 8.1 s

ANSWER:D

Use principle of conservation of energy

K.E gained = Energy supplied by the engine

V, mv2 = E = Pt

mv 2 t= ---

2P (2000)(45~) = 7_8s 2(259x!O')

A

v

D 7.8 s

An object of mass m moves with constant speed in a horizontal circle which has radius, r as shown in

the above diagram. Determine the value of work done and the change in momentum of the object

when it moves from point A to B?



CONFIDENTIAL* 3

Work done Change in momentum

A Zero mv

B 22mv'

zero 21

c zero mv2

D zero zero

ANSWER:A

Work done = 0 ; F always perpendicular to direction of V Change in momentum = mfl V

~-------

= m )v' + v2 - 2(v)(v)Cos60 = mv

6. An external torque whose magnitude and direction are fixed acts on a rigid body hence causing

the body to rotate about a fixed axis, which one ofthe statements below is correct?

960/1

A The magnitude of the external force which produces the torque increases.

B The angular velocity of the body does not change when the body is exerted by the

torque.

C The angular acceleration does not change when the body is acted on by the

torque.

D The rotational kinetic energy does not change when the body is acted on by the

torque.

ANSWER:C

Use r=la

Since I is constant then T is directly proportional to a

*This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL'


CONFIDENTIAL* 4

7

30.0 Kg

20.0 kg

The above figure shows a system in equilibrium with the 30 kg block just about to slide along a

horizontal surface. What is the coefficient of static friction between the 30 Kg block and the

horizontal surface?

A 020 B 050

T Sin 4..9::~ F, = ~R=~m, g ~ (1) T Cos 46 = m2 g ~(2)

(1 );;f2) : Tan 46 =

Therefore m, tan 46

~ = -

= 20tan 46' = 0.69 30

96011

c 0.69

*This question paper is CONFIDENTIAL until the examination is over.

D 0.87

R

30.0 Kg T T

20.0 kg

CONFIDENTIAL*


CONFIDENTIAL* 5

8

The diagram shows the position of two identical satellites at radius ofR1 and R2 around the Earth. IfU,

K and E represent the potential energy, the kinetic energy and the total energy of the satellites

respectively. Which one of the following statements states correctly the comparison of the three

energies for satellite P and S

A UP< U,, Kv> K,

B UP< Us, K, Us, Kv Us, K, < K,

ANSWER: c

K = GMm ~ K a. llr 2r

~ E a -llr

and

and

and

and

E,

CONFIDENTIAL' 6

A 8 c D

r r 0~ r

Answer: A

The particle is moving in SHM. F = - :~. where U is the potential energy. For potential energy

against distance graph, the gradient is overall positive followed by overall negative after t ~ 0

10 When damping is increased on an object undergoing resonant frequency oscillation, which change

does not occur?

A The amplitude of the driving oscillation decreases.

B The amplitude of the forced oscillation decreases.

C The resonant frequency decreases.

D The sharpness of the resonant peak decreases.

Answer: A

Answer A does not occur because the frequency of the driving oscillation is determined by the

oscillator and not by the driven system.

11 The diagram shows a long rope fixed at one end. The other end is moved up and down, setting up

a stationary wave.

vibration --.

ugo~d . / / -t ... ..:.l ..---'" ... fixed

end

What is the phase difference between the oscillations at X andY?

I I A 0 B -;rrad C -Jrrad

4 2

Answer: A

D 3 -;r rad 4

Particles of rope within 2 nodes are of same phase. Hence phase difference is zero.

12 A sound wave is emitted from a point source. The intensity of the sound wave is inversely

proportional to the square of the distance from the source. At a distance r from the source, the

am2plitude of the wave is 8X. What is the amplitude at a distance 2r from the source?

960/1 *This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL'


CONFIDENTIAL* 7

A 8X B 4X C 2X D X

Answer: B

fa-1

faA' 2 , r

2 1 1 A a-

2 orAa~then

r r k

A = ~therefore r

Ar=k

A2r2 = A1r 1 A, =A,r, = (sxXrL4x

r, 2r

13 A student blows across the top of a hollow bamboo pipe. The bottom of the pipe is closed by a finger so that a fundamental tone of frequency f is produced. Then the student blows again with the bottom of the pipe open. The tone that the student hears has a frequency

A equal tof B lower than/ C higher than/ D fluctuating in the range off

Answer: C.

In a closed pipe, the fundamental frequency f0 = c/4L where c is the speed of sound and L is the length of the pipe. However, for the open pipe, the fundamental frequency, f0"c/ 2L.

So, f o = 2fo

14 The potential energy of a two-atom system is represented by

of U represents

U a b h .. = -2

- ~. T e m1mmum value r r

A the potential energy of the system when the atomic separation is a minimum.

B the potential energy of the system when the atomic separation is a maximum.

C the potential energy of the system when the resultant force between the atoms is zero.

D the gravitational potential energy of the system when the atoms are at their lowest position.

Ans:A F = - dU =the gradient of the U-r graph dr

15 Which of the following is the stress-strain graph for a glass rod which is stretched until broken?

S!r~ss Stress Stress, Stress l ' __ //

/ /' '

I l

/ / I i / I /l I i 0 () I 0 0 /

Strain Strain Slrai~ S!fain

A B c D


CONFIDENTIAL* 8

Answer: A Glass is brittle. It obeys Hooke's Jaw and in its stress-strain graph there is no plastic

region. It breaks when the elastic limit is exceeded.

16. At what temperature is the r.m.s. speed of oxygen molecules the same as that of helium

molecules at 300 K?

[Relative molecular mass of oxygen~ 32, relative molecular mass of helium= 4]

A 38K B 849K C 1440 K D 2400 K

D: c1

= 3RTi = c2 = "8RT2 . M1 ' ~ 17 The pressure p of an ideal gas is related to the mean square speed ofthe gas molecules by the equation 71 = ~: T2 = ~2(300) K = 2400 K

I p =-nm < c2 >

3 What are represented by n and m?

n m

A Number of moles Mass of one mole gas

B Number of moles Mass of one molecule

c Number of molecules Mass of one molecule D Number of molecules per unit volume Mass of one molecule

Answer: D

nm represents the density of the gas which is mass/volume

Mass of gas= number of molecules x mass per molecule.

mass/volume~ number of molecules per unit volume x mass per molecule.

18 An ideal gas undergoes isothennal change. If its initial internal energy is U1 and its final internal energy is U2o the change in the internal energy is

A 0 D

Ans:A

19. The ratio of principal molar heat capacities for air is 1.4. When air of volume 500 cm3 at a

temperature of27"C is compressed adiabatically to a volume of 100 cm3, its new temperature is

A 187 "C B 298 "C C 326 "C D 385 "C

Ans: B



CONFIDENTIAL' 9

T v:(r-1) =TV (r-1) 1 I 2 2

300x500(14- 1) = T2x!00(14- 1)

T = 300x( 500 )o.4 2 100

T, = 57!.1K T, =298.l"C

20 One side of a room consists of a brick wall and a glass window. Both the brick wall and the glass

window have the same surface area. The thickness of the brick wall is 30 times that of the glass

1 . window, and the thermal conductivity of the brick is -that of the glass. The ratiO of rate of heat flow

6 through the brick wall to that of the glass window is

A 5: I B 180: 1 c 1 ; 5 D I :180

Ans:D

(Q) 1 (B1 -B,J Forbrickwall:- =-k.A ----(1) t b 6 30xg For glass: (7)g =kg{~ :ge, J----(2)

(1) ( 7l 1 1 1 ---=-x-=--(2) . ( 7) g 6 30 180

21 In an experiment to measure the thermal couductivity of a good conductor, a long test sample is

used so that

A the heat loss can be neglected

B the steady state is easily achieved

C the heat flow is parallel throughout the sample

D the temperature difference between the two ends of the sample is sufficiently large

Answer: D

Temperature gradient is small. A longer length is required to produce a sufficiently large

temperature difference.

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


CONFIDENTIAL' 10

A

The above figure shows three negative charges with charge -q or -2q are placed at the vertices A, B

and C of an equilateral triangle in free space. The length of each of the three sides is 2.0 m and S is

the idle point of the side BC. What is the electric field strength at pointS?

A q

along AS 6m:,

c _q_ along SA 6m:,

ANSWER:C

' / 2.0 m \ / 2.0 m

\_~~' // A

960/1

B .l!L 3Ju:,

D .l!L 3;r&,

along AS

along SA

SA= )2'-1 2 =.J3

Resultant E = Es + (-Ec) + EA but= Ea=Ec

(direction S towards A}


q

6nc0


CONFIDENTIAL* II

23. The diagram below shows the electric field lines between two parallel metal plates, A and B.

X lOOF

------~---.----~------

----'----;;--.----1-----,-- 0 v

If XY = _!_ XZ, determine the work done in moving an electron from X toY? 2

A C -8.0x!0-18 J

Answer: C E _ V _ !OOV _ SOV ---------

d Scm 2.5cm ++++++++

Wxv= qVxv = q (Vv-Vx)

=(-1.6 X 10'19 )(50-100)

= +8.0x!0'18J

A

~ B t t t t t t t t

24. A certain capacitor consists of a pair of parallel metal plates separated by a distance d in the air.

The capacitor is charged then disconnected from the charging source and immersed in a liquid with

permittivity E. Which of the following statements regarding the capacitor is correct?

A Both the charge stored in the capacitor and its capacitance decreased.

B Both the charge stored in the capacitor and its capacitance increased.

C The capacitance of the capacitor increased but the potential difference across it decreased.

D The capacitance of the capacitor increased but the potential difference across it increased.

Ans :C

960/1

For parallel plate capacitor

C - s,A 0 -d

and

Sincee>&0 , thusC>C0

Q=CV

*This question paper is CONFIDENTIA1 until the examination is over. CONFIDENTIAL*


CONFIDENTIAL* 12

Since Q ~constant, increase inC will result in decrease in V.

25. The circuit diagram shows a lO kQ resistor and a 40 kQ resistor connected across a charged

capacitor C,

After switch S is closed, the potential difference V across the capacitor varies with time t The graph of In V against tis given as shown below.

In V

2

0'------~20.,---~ l(s)

The capacitance of the capacitor is

A L25 X 10-5 F

Answer: C

B 2,00 X 10- 4 F

V ~ Voe-tiCR

lnV ~ lnV -t/CR

Gradient of graph= 26 =- c1 1 1 1 s -

1 ("R =10kQ + 40kQ = 40kQ-,

c L25 X 10-3 F

Capacitance, C= (10)(40

: 10

,) F = 1.25 x 10-3 F

D 2.50 X 10-3 F

26. When a potential difference V is applied across the ends of a copper wire which has diameter d

and length I, the drift velocity of the electron is v. What is the drift velocity if the same potential

difference is applied across a copper wire ofhalfthe diameter but twice the length?

A v

B v c v D 2v

4 2

Answer: B

96011 *This question paper is CONFIDENTIAL until the examination is over, CONFIDENTIAL*


CONFIDENTIAL* 13

ri' R1 =8R, [J t-''l ..... ~ . - Since R = ~-

27. The resistance of a piece of pure silicon decreases rapidly with increasing temperature because

A the drift velocity of the charge carriers increases.

B the number of charge cat riers increases

C the ratio of negative charge carriers to positive charge carriers increases

D the ratio of positive charge carriers to negative charge carriers increases

Answer: B a= p RA

e

so, (j 0:: when Tt, R .J., crt and a= R

=> a oc n ; when n t, hence, crt.

m

28. A battery of e.m.f. 2.0 V and negligible internal resistance is connected to four resistors as shown

in the diagram below.

1 J J 20 [l IOD 2.ov 1 p v ---< Q

10~ 100

What is the potential differer;ce between the points P and Q?

A OV B 0.33 V c 0.67 v D 1.00 V

Answer: B

The 20 Q , 1 OQ resistors and the 10 Q, I 0 Q resistors form the same potential dividers.

960/1 *This question paper is CONFIDENTIAL w1til the examination is over. CONFIDENTIAL*


CONFIDENTIAL* 14

---

20! ~v '""~ 3

WVT p -G>---to 10 3:.v 10!1 3

Hence the potential difference across P and Q ~ {;- 1) V ~ ~ V = 0.33 v

29 A milliammeter with negligible resistance gives a full scale deflection for 1 rnA. To convert it to a

voltmeter having a full scale deflection of 5 V,

A Connect a 5Q resistor in series with the milliammeter

B Connect a 50 D resistor in parallel with the milliammeter

c Connect a 5 X 1 03 n resistor in series with the milliammeter D Connect a 5 n resistor in series with the milliammeter and a 5 X 1 03 n resistor in parallel with the milliammeter

I mA

Answer: C R

--- VAB ~ 5V

V = l(R + r) = / R + l(O) Negligible resistance 5V~lrnA xR

.-. R = 5 X 102!1

B

30 An electron and a proton both entering perpendicularly in the same magnetic field separately. If

the speed of the electron is 10 times the speed of the proton. The ratio of the magnetic force on the

electron to the force on the proton is

A 1:1 B 1:5 c 1 : 10 D 10: I

Answer: D F~qvB therefore F, = lOq,

96011 *-This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*


CONFIDENTIAL* 15

31 If the current through a long solenoid is doubled while the coil's length is also doubled, keeping

the total number of turns constant, the magnetic field at a point inside near the axis is

A four times larger

B two times larger

c unchanged D half the original size

Answer: C

therefore B 1 = B

32 When the speed of an electrical motor is increased due to a decreasing load, the current flowing

through it decreases. Which of the following is the best explanation ofthis phenomenon?

A The induced back e.m.f. increases

B The resistance of the coil changes

C Frictional forces inereased as the speed increases

D At high speeds it is more difficult to feed current into the motor

Answer: A

Back emf in de motor, Eb = NBArosin mt ; As the load decreasing, ro will increase. Then eb will

increase, due to Eb oc w. Current flows in de motor is I= 5

- cb , hence Eb increase, I will increase. R

33 A circular flat coil of 200 turns of wire encloses an area of I 00 cm2 The coil is immersed in a

uniform perpendicular magnetic field Of0.50 T that penetrate the entire area. If the field drops to zero

in 200 ms, what is the current induced in the coil if it has a resistance of 25 0?

A 0.20A B O.SOA

Answer: A

M = BA = 0.5 x 0.0 I = 0.0050 Tm2

I - ;c - o ~o - ::-- ,..._ F1 _,

C l.OA D S.OA

34 An alternating current I which flow,, through a I 0 0 resistor is given by 1 = 3 sin I OOr. If I is in

amperes and tin seconds~ the mean power generated in the resistor is

A lOW B 30W C 45W D IOOW

Answer: C Mean power= .;, !02 R = Yo(3)' (10) = 45 W

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


CONFIDENTIAL* 16

35 The graph below shows the variation of reactance and frequency of an alternating current flowing

through three electrical components X, Y and Z.

Reactance

X

y

~--z "-----------+ Frequency

What are the components X, Y and Z?

X y z A Capacitor Resistor Inductor

B Inductor Resistor Capacitor

c Inductor Capacitor Resistor D Resistor Capacitor Inductor

Answer: B

X is an Inductor, XL c" wL

Y is a resistor. Resistance is independent of frequency.

Z . . I ts a capacitor. X = ---' 27r[C

36 The diagram shows a circuit of an inverting amplifier.

An input voltage of +2 V produces an output voltage of -8 V. Which statement about the circuit is

not true?

96011

A

B

c D

Rl The value of -is 4.

R,

The voltage gain is- 4.

When the input voltage is -1 V, the output voltage is+ 4 V.

When the input voltage is 2 V, the potential at point P is 2 V. Answer: D V r = 0 V



CONFIDENTIAL* 17

37 If the input voltages V1 and V2 in the circuit below are 50l!V and 90 l!Y respectively, what is

the output voltage? [Gain~ 105 ]

+ 15 v

~~~--------------~ov

Ans :B

v, 105

v, -~

~ l0 5 (40x!0-6 )

~4.0 v

B 4.0 V C +15V D -15V

38 The propagation of an electromagnetic wave is accompanied by electric field oscillations and

magnetic field oscillations. Which of the following statements is not true concerning the

electromagnetic wave?

96011

A The electromagnetic wave can be polarized.

B The electric field oscillations and the magnetic field oscillations are in phase.

C The directions of the electric field oscillation, the magnetic field oscillations, and the

electromagnetic field are perpendicular to one arwther.

D The oscillating frequency of the electric field and the oscillating frequency of the

magnetic field change when electromagnetic wave propagates from one medium to another

medium. Answer: D (factual)



CONFIDENTIAL* 18

39 The diagram below sbows a long glass rod with uniform diameter 2r. The left end of the rod has a semicircular convex surface of radius r. The refractive index of the glass is n. An object 0 is

placed on the left side and at the axis of the rod.

I I I I I I I I I

!~ ~~-----!"'- u ----71 v ' '

I I I I >I

If the image distance v produced in the rod is twice the object distance from the end of the rod, the

object distance u is

(n+2)r A 2n

Answer: B

~+~=~ u 't' ;

1 '1'1 11-1 -+-=-t~ 2u r

B (n+2)r

2 (n-1: c 2(n-1)r

(n+2)

n+2 n-1

2u r

' U= (11 + Z)r 2(n- 1)

D 2(1-n)r

(n +2)

40 A monochromatic light is directed towards a single adjustable slit to produce a diffraction

pattern on a screen as shown.

Intensity Central maximum

Subsidiary maxima

0

When the width of the slit is reduced,

A the intensity of the central peak will increase and the intensity of the subsidiary maxima will

decrease.

B the intensity of all maxima will increase and the width of the pattern will decrease.

C the intensity of all maxima do not change and the width of the pattern will increase.

D the intensity of all maxima will decrease and the width of the pattern will increase.

Answer : D The intensity will decrease when the width of the slit is reduced because there

is less light entering the slit. The width of the pattern will increase because the diffraction effect is

better when the width of the slit is narrower.

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


CONFIDENTIAL* 19

41 The diagram below shows a light beam incident on the surface of glass which has been coated

with an optical material.

f

If the wavelength of light in the optical material is A and the reflective index for the optical material and the glass are n 1 and n2 respectively, which ofthe following is the condition for the reflected light

beams x andy to experience destructive interference?

A ;\

t =- and n1 > n2 B

c )! t =- and n1 < n2 2 D t = i\ and n, < n,

Answer: B

A light beam experiences a phase change of n when reflected at the air-glass interface where the reflective index n1 of glass is greater than the reflective index n2 of air. Hence, the path

difference between light beams x andy ;

= Zt +-2

=2m+~=3m

This will produce destructive interference.

42 Which of the following is true based on the photoelectric effect?

A The emission of electrons will not occur for very low light intensity.

B The number of electrons produced per second does not depend on the intensity of light.

C The maximum velocity of the electrons increases when the wavelength of light decreases.

D The average kinetic energy of the electrons decreases when the frequency of light increases

Answer: C

K = .:::S_ 1.v max }.

A decreases, Kmax or Vmax increases



CONFIDENTIAL* 20

43 If electron A has twice the kinetic energy of electron B, the ratio of the de Broglie wavelength of

electron A to that of electron B is

A I: 2 B

Answer: B .4 = 2ER v/ =2vl VA= \~VB

c 2: 1 D

44 A hydrogen atom absorbs a photon and "' a result an electron is excited from the ground state to

the second excited state. If the n,h energy level of the hydrogen atom is given by E, =-13

6 eV the 2 , n

photon energy absorbed is

A 3.4 eV B 10.2 eV C 13.6 eV D 12.1 eV

ANSWER:D

Energy of photon absorbed= Energy excited from energy level n=l to energy level n=3

13.6 13.6 v =E3 -E1 =(-~eV)-( -~e ) = 12.1 eV

32 12

45 The property ofthe metal should be chosen as a target anode in an X-ray tube is

A a good conductor of electricity

B a good conductor of thermal energy

C a good insulator of thermal energy

D a good reflector of thermal energy

Answer: B

46 The mirror fixed at the end of the tube in a helium-neon laser system is used to

A improve the rate of production of electrons

B increase stimulated emission of photons

C absorbed part of the photons

D reduces the loss of laser light from the system

Answer: B

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


CONFIDENTIAL* 21

47 The mass of the nucleus ;;cu, the mass of nucleus :Hand the mass of ; n are 62.9296 u, 1.00783 u, and 1.00867 u respectively. What is the binding energy per nucleon for the nucleus?

A 5.40 X 10-13 J B D 8.85x 10-11 J

ANSWER: C

E = l\mC 2 = (29x 1.00783 + 34x 1.00867- 62.9296) (1.66x 10-27 )(3 x 108 )= 8.85 x J0- 11 J

Binding energy per nucleon= 8.85 x 1 o-11

63 =1.40x 10-12 J

48 A radioactive isotope of an element X experiences a series of decays until it becomes a stable

isotope for element X. In the process, the ratio of number of a particles emitted against the number of

~ particles emitted is

A 2:2 B 2: I c I : 2 D I : 1

Answer: C

Working: , u A-x 2 a z.lle---t z + -Ie 49 Helium nucleus is produced when a lithium nucleus is bombarded by a proton, as shown in the

below equation:

If the speed of light is c, mass of lithium is me. mass of proton is mp and mass of helium is mH , which

of the following expressions represents the energy released in this nuclear reaction?

A (me+ mp+2 mH) c2

B (me+mp-2mH)c2

C (me+ 2 mH - mp) c2

D (me+ 2 mH + mp) c2

Answer: B

50 Which one of the following is the main characteristic of a quark?

A It has zero rest mass B It travels at the speed of light

C It has fractional charge

D It is a combination of baryons

Answer: C



CONFIDENTIAL*

JAWATANKUASA PANEL TRIAL EXAM PHYSICS STPM

NEGERI SEMBILAN DARUL KHUSUS

MA Rl

CONFIDENTIAL* NS STPM TRIAL Marking Scheme 2011

Section A [ 40 marks]

Answer all questions in this section.

1 The heat capacity C of a substance is defined as "quantity of heat supplied to raise the temperature ika substance by 1 K. The heat capacity C of a solid is given by the expression

C=aT-bT3

where T is the absolute.temperature, a and bare constants with dimension.

(a) Determine the dimension of heat capacity, C.

C = Q = ML'r'(;-' llT

"' .. ... . ................. ..... \l}

(b) Write down the Sl unit of heat capacity, C

Jr' ............................................. (t)

(c) Find the units for a and b.

Unit of C

JK-'

JK-' Unit of a =

Unit of b

K JK-' K]

units of aT

(unit of a) .@ unit of bT

3 ............................ (!)

(unit of b) U

= Jr' ...................... (IJ

= Jr ..................... (!)

2 The rotating blade of a blender turns from rest with a constant angular acceleration 1. 50 rads-2 .

[1 mark]

[1 mark]

[3 marks]

(a) How long does it take to reach an angular velocity of 36.0 rads-1? [2 marks]

96012

m0 = 0 (starts from rest) m = m0 +at ......... (!)

t = m - m, a

36.0-0

1.50 = 24.0s

.............. (!)

1 *This question paper is CONFiDENTIAL until the examination is over. CONFIDENTIAL*


CONFIDENTIAL* 2 NS STPM TRIAL Marking Scheme 2011

(b) What is the number of revolutions in this time interval?

1 ' B = uYof + -- ar 2

B=0+I_(1.50)(240)' 2

= 432rad

................ (!)

. . . . . .. (1)

432 Number of rev=- = 68.8 ............. (1)

211:

[3 marks]

3 The graph shows the variation of extension with force of a wire before reaching the elastic limit. The original length of the wire is 2.0 m and its cross section area is 0.50 mm 2

10.6 I 10.4

j0.2

I 0 10 20 30 40 50 60 F(N)

(a) Calculate the work done to extend the wire to 1.20 mm.

1 Work done=- Fe

2 . . . . (1)

1 3 = -X 60 X 1.2 X 10-

2 = 0.036 J .. (1)

(b) Calculate the Young's modulus of the wire. Fl F I

Young's Modulus=~ =-x-= ~~-x-eA e A gradient A .................. (1)

60 2.0 = 3 X 6

1.2xl0 0.5xl0- ................... (!)

= 2.0 x 10 11 Nm-2 ..... . ....... (!)

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

[3 marks]

CONFIDENTIAL*



4 The graph shows the variation of pressure with volume for 0.128 mol of an ideal gasattemperarures 600 K and 850 K.

p (kPa)

T2 = 850K

By using the graph, calculate (a) the volume of gas at Y, and

AtY, pV=nRT ................................... (!)

V 0.128x8.3lx850 = sox 1 o' = L1Jx!O.,m 3

(b) the work done for the gas to change its state from W toY.

v Work done, W =nRT ln(-2 )

VI ..................... (I)

= 0.128x8.3lx850ln~10-J) (In 8.c ~tD-~) ~ 11.3~10 3

= 312J J ......................................... (!)

[2 marks]

[2 marks]

(c) If the gas at W experiences an adiabatic expansion to reach a temperature of 600 K, sketch the path to show the adiabatic expansion on the graph above. [1 mark]

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p (kPa)

80

Arrow with path from point

w .............. (!)

T2 = 850 K

T, = 600K 0 L-----:::"'::--------+ V(x 1 o-3 m 8 )

s.o 5




5 (a) A variable inductor is usually used to regulate the speed of an electric ceiling fan instead of a variable resistor. Explain. [2 marks]

By changing the reactance of the inductor, the potential difference and the current supplied to the fan can be varied. There is no power lost in the inductor. If a resistor is used, power is dissipated as heat loss in the resistor.

(b) A inductor with a inductance of 0.20H is connected to a 12 V ac supply with a frequency of 50 Hz. Calculate

(i) the reactance of the inductor. [1 mark]

(ii)

XL=27TjL

= 2;r x SOx 0.20 = 630 .. ,,,,,,,,, (l)

the rms current in the circuit.

J ::::: V,.ms rms XL "' ''' ''' '''.' .(1)

12

63 = OJ9A .............. (!)

[2 marks]

6 An air wedge is formed by placing a wire between two pieces of glass plates as shown in the diagram below. The length of the glass plate is 10cm. When monochromatic light of wavelength 475 nm is incident normally on the air wedge, interference pattern can be observed.

glass plates 4=============::1qr2 wire 10 em ------+

(a) Determine the diameter of the wire if 380 dark fringes are observed in the interference pattern formed. [3 marks]

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x=---2tanB

1 Ox! o-' 475xl o-9 = ,,,,,,,,,,,,,,,,,,,,,,, (1)

380 2tanB tan 6 = 9.025 X 10-4

Let the diameter of the wire bed

!!__ = 9.025x10-4 0.1 d = 9.0

......... ,, '''''' (1)

' (1)




(b) If the wire is pushed in slightly to reduce the length of the air wedge, explain any changes to'the fringe width. [2 marks]

The fririge width decreases

,i Fringe width, x = ............................... (!)

2tane When the wire is push in slightly, tlincreases, therefore the fringe width decrease ... (1)

7 (a) State two observations from experiment on photoelectric effect that cannot be explained by V.Jave theory. [2 marks]

(!)The maximum kinetic energy of the photoelectrons emitted does not depend on the intensity of the incident light. ..... " ....................... "......... (I)

(2) Photoelectrons can only be emitted when the frequency of the incident light exceeds the threshold frequency. ..... .... ...... ............ ......... ...... ........ ... (1)

(b) A monochromatic light wavelength of 350 nm illuminates the surface of a potassium metal with work function of 2.30 eV. Calculate the maximum speed of photoelectron emitted. [3 marks]

Using Einstein's equation, hf = ili0 + (, )'"" (1)

(6.63x!0-34 )x 3.0x!O' =2.30x(1.60x!0-19 )+_1_(9.11xl0-31 )v 2

350x!O 9 2 m" ......... (!)

v= 6.63xl05 ms-1 .......... (1)

8 (a) Explain what is meant by the half-life of a nuclide. [1 mark]

half life of a nuclide is the time taken for the number of radioactive nuclei to be reduced to half its

original number. (1)

(b) A source with decay constant 6.4 x 10'10 s1 has an activity of 5.7x 107 Bq. Calculate, for this source,

(i) the half-life (I) [2 marks]

Ti =ln2= Inz LOBX10'5 ..... (!) /z l 6Axia-1D

960/2 5 *This question paper is CONFIDENTIAL until the examination is over. CONFIDENTIAL*



(ii) the time taken for the activity to fall to 6.0'105 Bq. [2 marks]

A- A e-.l.< - 0

l A.

n- = -J.t An

. .... ( 1)

..... (1)

Section B [60 marks]

Answer any four questions in this section.

9 A car travelling along a flat road may be considered to have three forces acting on it as shown in the

diagram below.

force A of road on car

force C of Earth on car

Force A has a magnitude of 8200 Nand is at an angle of28 to the vertical. Force B is horizontal and has a magnitude 1500 N.

(a) Calculate

(i) the weight and the mass of the car, [2 marks] (ii) the resultant force on the car, [2 marks J (iii) the acceleration of the car. [I mark]

(b) For the car, motion is impossible without friction. Discuss what is meant by friction and the direction in which it acts on the car. In your answer, suggest another example where friction is useful. [3 marks]

(c) Describe a situation in which motion is produced without friction being required. [1 mark] (d) In a collision, when a truck of mass 12000 kg runs into the back of a car of mass 1200 kg, a constant

force of 72000 N acts for 0.25 s. Calculate the change in velocity of (i) the car, (ii) the truck.

(e) Suggest one way in which the conditions in (d) are unrealistic.

960/2 6 *This question paper is CONFIDENTIAL until the examination is over.

[3 marks] [2 marks] [1 mark]

CONFIDENTIAL*



Marking scheme : A

(a)(i) C =A cos 28'

= 8200 cos 28 = 7240 N ......... I c

8200 N weighi 7240 :\lass of car = -- = - = 73S ko

9 'li.S~ ......... 1

(a)(ii)

Horizontal resultant force= 8200 sin28- 1500 ......... 1 1500N

=2350N ......... 1

(a)(iii) .-1 net f-ore-e 235'0 "1 AccoeratiOn= -- = -- = 3.18m s~ :rrw 738 ......... 1

(b) Friction is a force that occurs when 2 bodies are in contact. ......... I

Friction acts in the opposite direction as the car moves forward, and vice versa. . ... I Friction is also useful in stopping the car. . ........ 1

(c) Free fall of a body through vacuum. .. ....... 1

(d) (i) By Newton's Second Law of Motion (The constant force acting on the object is equivalent to the change in linear momentum of the object per unit time for which the force acts)

F Ch10.~~ in nl.ruM


10 (a) (i) Explain what is meant by the frequency of vibration of an object. [I mark] (ii) Distinguish between the displacement of a vibrating object and the amplitude of vibration.

[2 marks] (b) Graph below shows the variation with displacement x ofthe acceleration a of a particle that attached

to the cone of a loudspeaker.

(i) Use the figure to explain why the motion of the particle is simple harmonic. [2 marks]

(ii) Show that the frequency of oscillation of the particle is 464Hz. [2 marks]

(c) The magnitude of the gradient of the line in the graph is G.

(i) Show that, for a particle of mass m oscillating with amplitude A, its maximum kinetic energy E,~, is given by Em"= Y, mGA 2 [3 marks]

(ii) Determine E,a, for the particle of mass 2.5 X I 0'3 kg.

(d) (i) Explain what is meant by resonance.

[2 marks]

[2 marks]

(ii) A washing machine has a drum which can rotate at high speed. Suggest why a concrete block, fixed at the base of the machine, helps to reduce the possibility of resonance. [I mark]

Marking scheme :

I O.(a)(i)The fiequency of vibration of an object refers to the number of cycles of vibration completed per unit

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time. ......... I

(ii) The displacement of a vibrating object refers to the distance moved from the mean or equilibrium position and the distance is measured in a given direction.

The amplitude of vibration refers to the greatest displacement from the mean position ......... .




(b) (i) The acceleration of is proportional to AND in opposite direction to ..its displacement. .:,: .. 0/2. __

(ii)

(c) (i)

(ii)

(d) (i)

1h ,. =- ,_:_:_ . 21


M.arking scheme :

(a) Assumptions of kinetic theory of gases: (take any four ) ( 4 marks)

L Gas consists of a large number of molecule which move freely and randomly. 2. Gas molecules collide elastically with each other and with the walls of container, 3. The volume of the gas molecule is very small can be neglected compare to the volume of gas. 4.The intermolecular forces are very small can be neglected

(b)

5.The time of collision between molecules is neglected compare to the time interval between two consecutive collision of a molecule

1 ' P = -p 3

1M , = --

3 r/~"

1 ' PV =-M ;M=massoflmoleofgas m 3

But PVm =RT

1 ' -M =RT 3

1 2 3 -M=-RT 2 2

1 ,, c' 3 -H m< ->=-RT ; M=NAm 2 A 2

(I)

(1)

So the average kinetic energy for a molecule of the gas is

1 , 3 R -m < c- >= --T 2 2 NA

3 = -kT

2

R where k=-

N A (I)

(c) Total kinetic energy for one mole ofmonoatomic gas 3 R

=--T 2 NA ... (I)

(I)

= ~ (6.02xl 023 )(1.38xl 0'23)( 400K) 2

= 4.99 X I 03 J (I)

960/2 10 *This question paper is CONFIDENTIAL until the examination is over. COJ'..'FIDENTIAL*



(d)

Number of mocules

Shape of the graphs (No simetri Curve) Labeling axes and T 1 & T2 Labeling v,, Vm & v for both graphs

( 1) ( 1) (!)

Molecular speed

(e) The area under graph T 1 and T2 are the same because the number of molecules i remams same. . ................................................................................. (1)

The value ofV,. V m and v are higher for higher temperature because the kinetic energy of the gas molecule will increase as the temperature increase............................................. (1)

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) Detem1ine 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 fiF and a resistor of large resistance 1.0 MO are co1111ected in series with a 12 V battery of negligible intemal resistance.

E s

c R

(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? [1 mark] (iii) Calculate the time taken for the capacitor to be 50% charged. [2 marks] (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]




Marking scheme :

C = '"'oA = B.SSx10-!.~xO.SO

2.21 x10-10 I (a) (i) d 2nx1o-a .................. (! )

(b)

Q=CV =2.21 x 10.10 x [75-(-75)] ............................... (1) =3.32xi0 8 C ............................. (l)

(112)QV (ii) Energy per unit volume=

Ad

(i)

12

VN

3.32. x10- 8x150

= 2.y().5x0.02()

= 2.49 x I 0"Jm3

------------------

(2)

0 '-----------+tis

(ii) 1 = CR

(iii)

= 3.0 s -I

1 -=1-e J>.o 2

I

e;;:c; = 2

....................... (I)

.................. (!)

...... . . (I)

.......................... (1)

................... (I)

I I A

1.2xl o'

0

(2)

tis

(iv) The capacitance of the capacitor decreases because d increases but the potential difference remain

constant . '' .................................. (1)

Therefore the charges on the capacitor decreases ...................... (l)

The energy stored decreases .......................................... (I)




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

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

(i) What is the effect of increasing the anode voltage to the characteristic X-rays and continuous X-rays spectra?

[2 marks] (ii) What is the effect of using a metal target of higher atomic

number? [2 marks]

(iii) What is the effect of using a metal target of higher atomic

number.

(c)

[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.

Relative intensity

[2 marks]

I I

Wavelength, t..

[2 marks]

(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]

Marking scheme :

(a) In the photoelectric effect, electrons are emitted from the metal surface when it is illuminated by light, that is photon .............................. (I)

In an X-rays tube, electromagnetic radiation, that is photons, are emitted from the metal surface when the metal is hit by electrons. .. ........................ (1)

(b) (i) There is a threshold value for anode voltage before X-rays can be generated. Variation in the anode voltage does not alter the energy of the characteristic lines. Increasing the anode voltage will shift the X-ray

minimum wavelength towards a lower value, widen the X-rays energy range, and cause overall increase in the X-rav intensity. .. ................................ Any 2

OR

Amin decreases, characteristic peaks remain at the same wavelengths but overall increase in the X-ray intensity.

Intensity lntensi

0 ;\min Wavelength




(b) (ii) Increasing the current in the filament will increase overall X-rays intensitv. This is because higher anode current means more electrons reach the target metal result in more X-rays photons. The positions of the characteristics peaks and the cut-offwavelencth are not altered. .. ....... Any 2

OR

The positions of the characteristics peaks and A,nm remains unchanged, but intensity increases for all wavelengths.

Intensity

length 0 -'rnm Wavelength

(b)(iii) Different metal targets will produce different characteristic X-ray energies because each metal target has . . 1 . . 1 (7) 1ts own umgue C1aractenstic mes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . -

OR Intensity

!""'"remains unchanged, but characteristic peaks shift to shorter wavelengths.

(c) The solid must be crystalline .......................... (J) The wavelength of the X-ray is comparable to the crystal spacing ..... (1)

(i) Maximum order= 3 ......... (1)

(ii) From Bragg's equation, 2dsin8 = nl, 11 = 3

(1)

. 3(0.154) s,ne = 2(0. 288) e = 53.3 (JJ

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.

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

(Given mass of neutron, mn=l.00867 u ; mass of proton, m,=J.00782 u ; atomic mass of Carbon-12,

Mc=l2.00000 u and atomic mass ofUranium-238, Mu=238.05079 u)

Wavelength

[2 marks]

[3 marks] [3 marks]

[!mark]

(c) An element of unknown mass is mixed with 'zC in a mass spectrometer. The radii of curvature of (the path of the ions) of the element and ions of 'tc are 26.2 em and 22.4 em respectively. What is the element? State any assumption made. [6 marks]

960/2 14 *This question paper is CONFIDENTIAL until the examination is over. COJ\'FIDENTIAL*


CONFIDENTIAL* 15 . NS STPM TRIAL Marking Scheme 2011

Marking scheme :

l (a) Binding energy per nucleon of a nucleus is the energy required per nucleon to completely separate the nucleons of the nucleus. . ................. : ... (1). Mass defect is the difference between the total mass of the nucleons and the mass of the nucleus ...... (!)

(b) (i) For Uranium-238

(c)

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flm = 92 X 1.00782 U + 146 X 1.00867 U -238.05079 U = 1.93447 u ............................. (l)

Binding energy per nucleon= A

1.9:>447 x931.5 Mev 238 (1)

= 7.57 MeV (1)

(ii) For Carbon-12 flm = (&mP + 6n~)- Me

= 6(1.00782 u + 1.00867 u)- 12.00000 u = 0.09894 u .................. (1)

L!..mcz

Binding energy per nucleon = A

O.G9394 x 931..5

12 ...................... (1)

= 7.68 MeV ............................. (I)

Since the binding energy per nucleon ofuraninm-23 8 is less than the binding energy per nucleon of

carbon-12. Therefore uranium-238 is less stable than carbon-12 .................. (1)

mVZ qvB=-

r (I)

m= (~)r Assuming that the ions of the element have the same charge as the ions of

1~c, therefore

m ocr A ocr .................. (I) A 2;6.2 ---12 22.4 ...................... (1)

A = 14 .................... (I) The element is nitrogen ................... (I)

15

.............. (1)



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