N9 STPM Trial 2010 Physics [w Ans] [B2D6F3EE] (1)

8/10/2019 N9 STPM Trial 2010 Physics [w Ans] [B2D6F3EE] (1)

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JAWATANKUASA PANELTRIAL EXAM PHYSICS STPM

NEGERI SEMBILAN DARUL KHUSUS

http://edu.joshuatly.com/http://www.joshuatly.com


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960 PHYSICS STPM

CONSTANT VALUES

STPM DATA BOOKLET

For 960 PHYSICS - PAPER 1 AND PAPER 2

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

Speed of light in free space c = 3.00 x 108

ms-1

Permeability of free space o = 4x 10-7Hm-1

Permittivity of free space o = 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

mol-1

Avogadro constant NA= 6.02 x 1023

mol-1

Boltzmann constant k = 1.38 x 10-23

JK-1

Gravitational constant G = 6.67 x 10-11

Nm2kg

-2

Acceleration of free fall g= 9.81 ms-2

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



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1 Which of the following quantities has no units?

A Work

B Strain

C Momentum

D Youngs modulus

2 A body moves with constant acceleration experiences a constant

A rate of change of force

B rate of change of distance

C rate of change of velocity

D rate of change of displacement

3 A ball is projected vertically upwards reaching a maximum height of 50 m. Its velocity after 4.0 s is

A 7.9 m s-1upwards

B 9.7 m s -1upwards

C 7.9 m s-1

downwards

D 9.7 m s

-1

downwards

4 A sky diver falls with terminal velocity. Which of the following statements is an application of Newtons

third law?

A The resultant force acted on him is zero

B His weight is balanced by the air resistance acted on him

C His weight is equal to the force on the Earth by him

D The force of gravity acted on him is equal to the resistance acted on him

5 A body of mass 2.0 kg is acted upon by a force as shown in the graph below.

If the gain in momentum by the body in time 4.0 s is 10 kgms-1

, the value ofxin the graph isA 4 N B 6 N C 8 N D 10 N

6 Centre of mass of a body is

A the point at which the body will rotate.

B the same as centre of gravity of the body.

C the point at which the weight is considered to act.

D the point at which the mass is considered to concentrate.

Force/N

Time/s

x

0 4321



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7 A pendulum bob is whirled round on a smooth horizontal surface by a string of length lat a constant rate.

If the tension in the string is kept constant, which of the following graphs represents the relation between the

speed vof the pendulum bob and the length lof the string?

8 A torque on a rigid body is the

A rotational analogue of mass

B rotational analogue of force

C rate of change of linear momentum

D rate of change of rotational kinetic energy

9 A satellite of mass m moves round the Earth in an orbit of radius r takes time T to complete one

revolution. Another satellite of mass 4mtakes the same time Tto complete one revolution. The radius of the

orbit of the second satellite is

A r4

1 B r

2

1 C r D 2r

10 Which of the following statements regarding simple harmonic motion is true?

A Acceleration is constant

B Amplitude varies with time

C Frequency decreases with timeD Speed is maximum at equilibrium

11 A particle performs simple harmonic motion. Its velocity leads its displacement by a phase of

A4

B

2

C D 2

l

l

A B

CD

v v

vv

l

l0 0

00



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12 A car with a defective suspension system moves over a bump on the road. Which of the following graphs

shows correctly how the height h of the centre of gravity of the car varies with time t?

A B

D

C

D

13 Two points on a progressive wave differ by phase of8

3radians. The distance between them is 0.36 m.

The wavelength is

A 0.12 m B 0.48 m C 0.96 m D 1.92 m

14 Two progressive waves are represented by the equations

y1= 3.0 sin (20t + 2x) and y2= 2.0 sin (10t + 5x)

The ratio of the intensity ofy1to they2is

A 0.40 B 1.50 C 2.25 D 4.00

15When a student blows slowly across an open end of a test tube, a fundamental note of frequency f is

produced. If the student blows harder, the frequencies of the other overtones will be

A 2f, 3f B 3f, 3f C 3f, 4f D 3f, 5f

16 Beats of frequency 6.0 Hz is produced by the superposition of two notes of frequencies f1and f2. The

waveform of the resultant wave is as shown.

The values of the frequenciesf1andf2are

A f1= 50 Hz,f2= 44 Hz

B f1= 53 Hz,f2= 47 Hz

C f1= 75 Hz,f2= 69 Hz

D f1= 210 Hz,f2= 204 Hz



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17 Which of the following statements is true about the energy and force between atoms in a diatomic

molecule?

A The force is zero when the potential energy is minimum

B The attractive force is maximum when the potential energy is zero

C The force is inversely proportional to the square of the separation between atoms

D The force changes from repulsive force (when the separation is large) to attractive

force (when the separation is small)

18 A wire is stretched beyond the elastic limit and then the applied force is removed. Which of the following

statements describes correctly the behavior of the stretched wire?

A The wire snaps

B The wire returns to its original length

C The wire will have permanent extension

D The length of the wire will remain the same as it is when the force is removed

19 A rod of original length

and cross-sectional areaAis stretched by e. IfEis the Youngs Modulus of the

rod, and the change in cross-sectional area of the rod can be neglected, the energy per unit volume stored in

the rod is

A2

2

2

Ee B

22

EeA C

2

Ee D

EeA

20 The process of expansion for a fixed mass of an ideal gas is shown in the graph below.

The ratio ofspeedsquaremeanrootinitial

speedsquaremeanrootfinal for the gas molecule is

A2

3 B

4

3 C

4

3 D

8

3

p / 105Pa

Final state of as

Initial state of gas

8

6

4

2

0 0.2 0.4 0.6 0.8 V/ m

3



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x x x x x x x x x x

rod

2

0 x

21 In a mixture of two monatomic gases YandZat thermal equilibrium, the molecular mass of Yis double

the molecular mass ofZ. The mean translational kinetic energy for Zis 8.2 x 10-21

J per molecule. The mean

translational kinetic energy per molecule for Yis

A 4.1 x 10-21

J per molecule

B 5.5 x 10-21

J per molecule

C 8.2 x 10-21J per molecule

D 16.4 x 10-21J per molecule

22 The isotherms for a fixed mass of an ideal gas at thermodynamic temperatures T1and T2are shown in the

graph below.

If T1is 273.15 K, the ice point, then the value T2isA 91.05 K B 364.20 K C 364.21 K D 819.45 K

23 Which of the following is true concerning the adiabatic expansion of an ideal gas?

A The internal energy of the gas increases

B The temperature of the gas does not change

C The r.m.s speed of the gas molecules decreases

D The external work done is more than the change in internal energy

24 The variation of temperature along a lagged metal rod of uniform cross section area which is in steady

state is shown in the diagram below. Two ends of the rod are maintained at temperature of 1and 2.

Which of the following is true about the rate of heat flow through the rod,

dt

dQ and the thermal

conductivity, kof the material with distance,xfrom the hot end?

dt

dQ k

A Decreases Unchanged

B Increases Unchanged

C Unchanged Decreases

D Unchanged Increases

x x x x x x x x x x

1 lagged

pV

0 p

3x

x

T2

T1



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25 Two properly insulated uniform rods,Xand Yare arranged as shown in the figure below.

The thermal conductivity of Xis 10 times that of Y. The rods are in steady condition. Which one of the

following statements is correct?

A The rate of heat flow inXis greater than in Y.

B The temperature gradient alongXis the same as that along Y.

C The temperature

at the interface betweenXand Yis nearly 0 C.

D The rate of heat flow will increase if the length of rodXis shortened but the temperatures 0 C and

100 C of remain the same.

26 The graphs below are drawn to the same scale show the electric potential Vbetween two points Pand Q.

Which one shows that the electric field strength between Pand Qis the strongest?

C D

VV

00 QP P Q

0 C100 C

X Y

Thermal insulator C

50 mm 5 mm

A B

V

0 QP

V

0Q

P



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27 A capacitor Cis charged by using the circuit as shown in the figure below.

When switch S1is opened and then switch S2is closed, the reading of the galvanometer G is

A zero

B not zero

C decreasing linearly with time until zero

D decreasing exponentially with time until zero

28 Which of the following statements explains correctly the decrease in resistivity of an intrinsic

semiconductor when its temperature increases?

A The drift velocity of the charge carriers increases with temperature.

B The number of charge carriers per volume increases with temperature.

C The rate of collision between the charge carriers and atoms increases with temperature.

D The amplitude of vibrations of the atoms of a semiconductor increases with temperature.

29 When a potential difference V is applied across a copper wire of length L, the drift velocity of the

electron in the wire is ve. If the length of the wire L changes, which of the following graphs shows correctly

the variation of vewithL?

S2

S1

G

High resistance

-+C

A B

C D

ve

L

ve

L

LL

veve



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YX

4R

4R

R

E = 3.5 V

r= 1.5

30 3 resistors with resistanceR, 4Rand 4Rrespectively are connected to a battery of e.m.f, E= 3.5V with

internal resistance,r= 1.5 as shown in a circuit below.

If the potential difference across pointXand point Yis 2.0 V, the value ofRis

A 1.0 B 2.0 C 3.0 D 4.0

31 A galvanometer with negligible internal resistanceand a full scale deflection of 5 mA is modified for use

as a voltmeter with a full scale deflection of 10 V. The correct modification for the required circuit is

A A resistor of 2 x 10

2

is connected in series to the galvanometerB A resistor of 2 x 10

3is connected in series to the galvanometer.

C A resistor of 2 x 104is connected in series to the galvanometer.

D A resistor of 2 x 105is connected in parallel to the galvanometer.

32 Two concentric ringsXand Yare placed on the horizontal plane, as shown in the diagram below.

The radius of ringXis r1= 1.0 m and r2= 2.0 m. The current flows in ring Yis four times the current in

ringXbut in the opposite direction. The resultant magnetic flux density at the centre of the rings is

A Io5.1 and points towardsN

B Io5.0 and points towardsN

C Io5.0 and points towards S

D Io5.1 and points towards S

X

Y

N

r1 r2

I

4I



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33 An electron is launched with velocity vinto a space which has magnetic flux density B and an electric

field strengthEthat are perpendicular to each other. If the velocity vof the electron is uniform, then

AB

Ev ; vis perpendicular toBandE

BE

Bv ; vis perpendicular toBandE

CB

Ev ; vis perpendicular toB orE

DE

Bv ; vis perpendicular toBorE

34 A rectangular coil PQRSis placed in a uniform magnetic field as shown in diagram (a). The variation of

the magnetic flux densityBwith time t is as shown in diagram (b).

Which one of the following graphs shows variation of the magnitude of induced e.m.f.E with time t ?

4T3T2TT0

E

B

E

C D

4T3T2TT0

A

4T3T2TT0

E

4T3T2TT0

E

tt

t t

B

T 2T 3T0 4T

Diagram (b)

Diagram (a)t

P Q

S R



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35 Which of the following produce voltage or current by self-induction?

A High voltage or current produced in a transformer

B High voltage produced in a Van de Graff generator

C High voltage produced when the switch in a solenoid circuit is opened

D Current flows in a copper plate when the plate is oscillating in a magnetic field

36 An alternating currentIrepresented by the equationI = 4sin100tflows in a resistor of 5.0 . IfI is in

ampere and tin seconds, the mean power dissipated in the resistor is

A 10 W B 20 W C 40 W D 160 W

37 The op-amp in the circuit shown contains a feedback resistorRf.

The function of the feedback is

A To increase the gain

B To oppose the input a.c.

C To increase the bandwidth

D To make the amplifier into non-inverting

38 Which of the following provides direct experimental evidence that light is a transverse wave but not a

longitudinal wave?

A Light can be polarized.

B Light can be diffracted.

C Two coherent light waves can be made to interfere.

D The intensity of light from a point source is inversely proportional to the square of the distance from

the source.

39 A point object in air is placed at a distanceu in front of a glass sphere of radius r. If the refractive index

of glass is nand the image formed inside the glass sphere is 2u, the ucan be written as

A rn

n

)2(

)1(2

B r

n

n

)2(2

)1(

C r

n

n

)1(2

)2(

D r

n

n)

2(

40 A monochromatic light illuminates onto two narrow parallel slits and the interference pattern is observed

on a screen at some distance beyond the slits. Which modification will increase the separation between the

dark fringes of the interference pattern?

A Increase the distance between the slits

B Use monochromatic light of higher frequency

C Use monochromatic light of longer wavelength

D Decrease the distance between the screen and the slits

Rf

_

+

R



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41 A monochromatic light of wavelength 600 nm illuminates a diffraction grating of 3105lines per metre.

If the zero order is not being considered, how many diffracted fringes can be observed?

A 2 B 5 C 7 D 10

42 The results of the photoelectric effect in Milikans experiment is shown in the graph below.

The intercept of thef-axis of the graph atfodepends on

A the work function

B the stopping potential

C the intensity of radiation

D the frequency of radiation

43 The de Broglie wavelength of a bullet of mass 0.02 kg which moves at speed of 300 ms-1is

A 7.3 x 10-36m

B 1.8 x 10-35

m

C 1.1 x 10-34

m

D 9.9 x 10-33

m

44 The frequency of electromagnetic radiation emitted by a hydrogen atom which undergoes a transition

between energy levels of -1.36 x 10-19

J and -5.45 x 10-19

J is

A 1.36 x1014Hz

B 4.09 x 1014 Hz

C 6.17 x 1014 Hz

D 6.17 x 1019

Hz

45 The cut-off frequency in the continuous X-ray spectrum from an X-ray tube depends on the

A target metal

B anode current

C filament current

D voltage across the tube

46 The main principle used to produce laser is

A reflection of light

B radioactive decay

C stimulated emission of photons

D spontaneous emission of photons



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47 The rest masses of deuteron H21 , proton and neutron are 2.0150 u, 1.0096 uand 1.0097 urespectively.

A deuteron may disintegrate to a proton and neutron if it

A emits a photon energy 3.1 MeV

B emits a photon of energy 2.0 MeV

C captures a photon of energy 2.0 MeV

D captures a photon of energy 4.1 MeV

48 A sample consists of two radioactive nuclides in equal proportion but each has a different decay constant.

Which graph shows the relation between the initial activity Ao and the initial total number of radioactive

nucleiNoof the sample?

49 The binding energy of carbon-12 in MeV is

[Mass ofcarbon-12= 11.996706 u, mass of proton, mp= 1.007276 u, mass of neutron, mn= 1.008665 u]

A 0.511 MeV

B 9.11 MeV

C 14.8 MeV

D 92.4 MeV

50 Which of the following elementary particles has quark?

A Proton

B Photon

C Electron

D Neutrino

N0

Ao

A

Ao

D

N0

Ao

C

N0

B

Ao

N0



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1

JAWATANKUASA PANELTRIAL EXAM PHYSICS STPM

NEGERI SEMBILAN DARUL KHUSUS



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960 PHYSICS STPM

CONSTANT VALUES

STPM DATA BOOKLET

For 960 PHYSICS - PAPER 1 AND PAPER 2

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

Speed of light in free space c = 3.00 x 108

ms-1

Permeability of free space o = 4x 10-7Hm-1

Permittivity of free space o = 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

mol-1

Avogadro constant NA= 6.02 x 1023

mol-1

Boltzmann constant k = 1.38 x 10-23

JK-1

Gravitational constant G = 6.67 x 10-11

Nm2kg

-2

Acceleration of free fall g= 9.81 ms-2

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



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3

Section A [40 marks]

Answer allquestions in this section.

1 A uniform circular disc, at rest, has mass 10 kg and radius 0.2 m. When a force of 10 N is applied

tangentially to the disc for 10 s, calculate

(i) the angular velocity,(ii) the kinetic energy,

acquired by the disc about its central axis at the end of 10 s. [4 marks]

[Moment of inertia of circular disc, I=2

1MR

2]

2 A car body of mass 1000 kg is supported by a system of springs. When a passenger of mass 80 kg sits

inside the car, the car is depressed by 5.0 cm.

(a) Calculate natural frequency of the car body. [3 marks]

(b) On the same axes, sketch graphs to show the variation of displacement against time for oscillation

which is

(i) underdamped, [3 marks]

(ii) critically damped.



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3 (a) Sketch and label graphs on the same axes to show how the potential energy Uand the force between

atoms Ffor two atoms, depend on the separation, rof the atoms. [2 marks]

(b) What is the change in the shape of the F-rcurve if the material has higher Young Modulus? Explain

your answer. [2 marks]

.

.

.

4 A fixed mass of an ideal gas undergoes changes of pressure and volume at temperatures 283 K and 1132 K

is shown in the diagram below.

If the r.m.s. speed of the gas molecules at 283 K and 1132 K are v1and v2respectively, determine

(a) the ratio of2

1

v

v. [3 marks]

(b) the number of mole of the gas. [2 marks]

6

4

2

0 1 2 3 V(x10-3

)/m3

P(x105)/Pa

283K

1132K



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5 A small positive charged sphere with mass 0.8 g suspended by a light string from the ceiling in an

electric field of intensity 900 NC-1, is shown in the diagram below.

In the equilibrium position shown, the string makes an inclined angle of 30owith the vertical line.

(a) Label all forces that act on the sphere on the diagram. [3 marks]

(b) Determine the magnitude of the charge on the sphere. [3 marks]

6 Diagram below shows a circuit which uses an operational amplifier.

The voltage supplied to the operational amplifier is from a battery of e.m.f 6 V and with negligible internal

resistance.

(a) Calculate the gain of the operational amplifier. [1 mark]

E300

_

+Vi

+6 V

-6 V Vo

1 k

100 k



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(b) Sketch a graph to show the variation of output voltage Vowith input voltage Viin the rangeof Vi= 0V to Vi= 0.1 V. Explain the shape of the graph obtained. [3 marks]

7 A lens made of glass with refractive index of 1.58 has one concave surface with radius of curvature of

20 cm and one flat surface.

(a) Calculate the focal length of the lens. [2 marks]

(b) A candle is placed 30 cm in front of the concave surface of the lens. Where will the image be formed? [3 marks]



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8 When Uranium-235 nuclei are fissioned by slow-moving neutrons, the induced fission reaction may be

represented by the nuclear equation as follows:

energy2Sr 1095

38

139

54

1

0

235

92 nXenU

The binding energy per nucleonEfor a number of nuclides is given in the table below.

Nuclides E/ MeV

Sr9538 8.74

Xe13954 8.39

U23592 7.60

(a) What is meant by the binding energy per nucleon of a nucleus. [1 mark]

..

..

..

(b) Show that the energy released in this reaction is approximately 211 MeV. [3 marks]

(c) The energy released in another nuclear reaction is 163 MeV. Suggest, with a reason, which ofthe two reactions is more likely to occur. [2 marks]

..

..

...



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Section B [60 marks]

Answer any fourquestions in this section.

9. (a) (i) State Newtons Law of Universe Gravitation. [2 marks]

(ii) Define gravitational field strength. [1 mark]

(iii) Newtons Law of Universe Gravitation may apply to point masses separated by a distance

r. Suggest why, although planets are not point masses, the law may be used to explain the

motion of planets about the Sun. [1 mark]

(iv) Use Newtons law of gravitation and the definition of gravitational field strength to derive

an expression for the gravitational field strength gat a distance rfrom a point massM.

[2 marks]

(v) Explain why the acceleration of free fall is approximately constant between the Earths surface and

a point about 1000m from the surface of the Earth. [2 marks]

(b) A planet orbits the Sun in a circular path of radiusR. The period of the orbit is T.

(i) Show that3

22 4 R

GMT

, whereMis the mass of the Sun and Gis the gravitational constant.

[3 marks](ii) Diagram below shows how log Tvaries with logRfor the various planets.

Use equation in (b) (i) to determine an equation for this graph. Explain how the graph verifiesthe of relation T

2= (constant)R

3. [4 marks]



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10 (a) State two characteristics of standing waves. [2 marks]

(b) A small loudspeaker that emits sound of frequency 790 Hz is placed above a glass resonant

tube containing water, is shown in the diagram below.

Water is slowly drained out from the resonant tube. Loud sounds are first to be heard when the length

l = 9.6 cm and again when l = 30.5 cm.

(i) Describe qualitatively the formation of standing waves in the air column. [3 marks]

(ii) Explain these observations in the above resonant tube. [4 marks]

(iii) Calculate the speed of the sound in air and the end correction. [4 marks]

(iv) If the experiment is repeated when the room temperature is higher, explainshow the resonantlengths would be affected. [2 marks]

11 (a) Explain what is meant by (i) temperature gradient,

(ii) thermal conductivity. [2 marks]

(b) Two different metal rods of the same length and cross sectional area are joined end to end. One end

of the metal rod is maintained at 100oC and the other end is maintained at 0

oC. Sketch labeled

graphs to show the variation of the temperature gradient with distance along the joined rods if both

sides are

(i) perfectly insulated; [2 marks]

(ii) not insulated. [2marks]

Explainalso how the graph for perfectly insulated rods in (i) can be used to compare the thermal

conductivities of the materials of the rods. [2 marks]

(c) The base of the room in a house consists of wooden board which is 15 mm thick and of area

200 m2. The thermal conductivity of the board is 0.15 Wm

-1K

-1. The temperature in the room is

maintained at 0 oC and the base is at 20 oC.

Calculate the rate of heat energy into the room through the base. [2 marks]

If the owner now decides to insulate the room by covering the board with a layer of insulating

material of thickness 10 cm and thermal conductivity of 0.030 Wm-1K-1, calculate

(i) the temperature of the board and insulating material interface [3 marks]

(ii) the new rate of heat energy transfer into the room. [2 marks]

[ Assume the board and insulating material are in good contact ]

Air column

Water

Small loud speaker

Water drained out slowly



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12 (a) Explain what is meant by Hall effect? [2 marks]

(b) A piece of n-type semiconductor connected to a battery so that a currentIflows, is shown in thediagram below.

This current is caused by negative charge carriers or electrons flowing with drift velocity, . A uniform

magnetic fieldBis applied vertical point into the plane and perpendicular to the semiconductor. When

the Hall effect occurs in the semiconductor, a steady potential difference, VHis created between

the opposite horizontal surfaces as shown in the diagram.

(i) By referring to the diagram, explain and derivean expression of Hall potential difference, VHin

terms of magnetic fieldB, currentI, width t, number of charge carrier per unit volume nand

charge carrier, e. [6 marks]

(ii) Explain why the Hall effect occurs in a conducting metal is less efficient compare tosemiconductor. [2 marks]

(iii) Statethe observation on the deflection of the pointer of the galvanometer if thep-typesemiconductor is used. Explain your answer. [3 marks]

(iv) If a piece of semiconductor with width 4.5 mm carries a current of 250 mA is placed into a

uniform magnetic field of 2.0 T and a Hall potential difference of 10.5 mV is created. Determine

the number of charge carrier per unit volume, inside the semiconductor. [2 marks]

GalvanometerVH

t

I

n-type semiconductor

d



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13 (a) When an electron enters perpendicularly into a uniform magnetic field of 0.1 T, the electron will

moves in a circular path with radius 210-3m. Explain this phenomenon and hence calculate the

wavelength associated with the electron. [5 marks]

(b) What do you understand by

(i) photon,

(ii) de Broglies relationship,

(iii) wave particle duality? [3 marks]

(c) Some of the electron energy levels for a hydrogen atom is shown in the diagram below.

The level n= 1 is the ground state.

(i) Refer to the energy levels, explain briefly how an electric discharge lamp filled with a

hydrogen gas gives rise to a visible line spectrum. [4 marks]

(ii) Calculate the shortest wavelength of electromagnetic radiation that can be emitted by a

hydrogen atom. [3 marks]

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

statement. [2 marks]

(b) (i) Explain the differences between the process of production of continuous X-rays and the process

of production of characteristic X-rays in an X-ray tube. [4 marks]

(ii) Explain why X-rays are not produced from hydrogen through transition of energy level. [2 marks]

(c) In an X-ray tube, electrons are accelerated by 300 kV to bombard a metal target. The X-rays

produced are analysed in the spectrum obtained.

(i) Sketch a graph of intensity against wavelength to show the typical spectrum possibly obtained.[2 marks]

(ii) Calculate the minimum wavelength in the X-ray spectrum. [3 marks]

(iii) Explain how the graph in (c) (i) will vary if a higher voltage is used in the X-ray tube. [2 marks]

n=1

n=2

n=3

n=4

n=5

n=

2.2 10-18

J

5.4 10-19

J

2.4 10-19

J

1.4 10-19

J

8.8 10-20

J

0



26/55

Answer for PHYSICS TRIAL STPM NEGERI SEMBILAN 2010

1 B 11 B 21 C 31 B 4

2 C 12 C 22 D 32 B 4

3 C 13 D 23 C 33 A 4

4 C 14 C 24 D 34 A 4

5 A 15 D 25 D 35 C 4

6 D 16 B 26 C 36 C 4

7 D 17 A 27 D 37 C 4

8 B 18 C 28 B 38 A 4

9 C 19 A 29 C 39 C 4

10 D 20 A 30 C 40 C



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

1

1. Which of the following quantities has no units?

A Work

B Strain

C Momentum

D Youngs modulus

2. A body moving with constant acceleration experiences a constant

A rate of change of force

B rate of change of distance

C rate of change of velocity

D rate of change of displacement

3. A ball is projected vertically upwards reaching a maximum height of 50 m. What is its

velocity after 4.0 s?

A 7.9 m s-1upwards

B 9.7 m s -1upwards

C 7.9 m s-1downwards

D 9.7 m s-1

downwards

4. A sky diver falls with terminal velocity. Which of the statements below is an application

of Newtons third law?

A The resultant force acting on him is zero

B His weight is balanced by the air resistance on him

C His weight is equal to the force on the Earth by him

D The force of gravity on him is equal to the resistance on him

5. A body of mass 2.0 kg is acted upon by a force as shown in the graph below.

If the gain in momentum by the body in time 4.0 seconds is 10 kg m s-1, what is the

value ofx?

A 4 N B 6 N C 8 N D 10 N

F/N

Time/s

x

0 4321



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2

6.

A pendulum bob is whirled round on a smooth horizontal surface by a string of length lat

a constant rate. If the tension in the string is kept constant, which of the following graphs

represents the relation between the speed vof the pendulum bob and the length lof the string?

7. A torque on a rigid body is the

A rotational analogue of mass

B rotational analogue of force

C rate of change of linear momentumD rate of change of rotational kinetic energy

8. Centre of mass of a body is

A The point at which the body will rotate.

B The same as centre of gravity of the body.

C The point at which the weight is considered to act.

D The point at which the mass is considered to concentrate.

9. A satellite of mass m going round the Earth in an orbit of radius r takes time T to

complete one revolution. Another satellite of mass 4mtakes the same time Tto complete one

revolution. The radius of the orbit of the second satellite is

A r4

1 B r

2

1 C r D 2r

l

l

A B

CD

v v

vv

l

lO O

OO



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3

10. Which of the following statements regarding simple harmonic motion is true?

A Acceleration is constant

B Amplitude varies with time

C Frequency decreases with time

D Speed is maximum at equilibrium

11 A particle performs simple harmonic motion. Its velocity leads the displacement by a

phase of

A4

B

2

C D 2

Answer: B

tvtxdt

dxv

txx

o

o

coscos

sin

12 A car with a defective suspension system moves over a bump on the road. Which of the

following graphs correctly shows how the height h of the centre of gravity of the car varies

with time t?

A B

D

C D

Answer: C

Damped oscillation, h > 0.

13 Two points on a progressive wave differ in phase by 3/8 radians. The distance between

them is 0.36 m. What is the wavelength?

A 0.12 m B 0.48 m C 0.96 m D 1.92 m



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4

Answer : D

3/8 radians is equivalent to 0.36 m, 2radians

is equivalent to , = 1.92 m

14 Two progressive waves are represented by the equations

y1= 3.0 sin (20t + 2x) andy2= 2.0 sin (10t + 5x)

Which of the following is the ratio of the intensity ofy1to that ofy2?

A 0.40 B 1.50 C 2.25 D 4.00

Answer : C

Intensity (amplitude)2.

(a1)2= (3.0)2

(a2)2= (2.0)2

15 When a student blows slowly across an open end of a test tube, a fundamental note of

frequencyf is produced. If the student blows harder, the frequencies of the other overtones

are

A 2f, 3f B 3f, 3f C 3f, 4f D 3f, 5f

Ans:

16 Beats of frequency 6.0 Hz is produced by the superposition of two notes of frequenciesf1

and f2. The waveform of the resultant wave is as shown. Which of the following gives the

values of the frequenciesf1andf2?



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5

A f1= 50 Hz,f2= 44 Hz

B f1= 53 Hz,f2= 47 Hz

C f1= 75 Hz,f2= 69 Hz

D f1= 210 Hz,f2= 204 Hz

Answers: B

Freq. of the resultant wave,

HzfHzf

Hzf

Hzff

Hzff

ff

47,53

1062:)2()1(

)2(0.6.,FreqBeat

)1(100

15.0

5.7

2

21

1

21

21

21

17 Which of the following statements is true about the energy and force between atoms in a

diatomic molecule?

A The force is zero when the potential energy is minimum

B The attractive force is maximum when the potential energy is zero

C The force is inversely proportional to the square of the separation between atoms

D The force changes from repulsive force (when the separation is large) to attractive

force (when the separation is small)

18 A wire is stretched beyond the elastic limit and then the applied force is removed. Which

of the following statements describes correctly the behavior of the stretched wire?

A The wire snapsB The wire returns to its original length

C The wire will have permanent extension

D The length of the wire will remain the same as it is when the force is removed

19 A rod of original length and cross-sectional areaAis stretched by e. IfEis the Young

Modulus of the rod, and the change in cross-sectional area of the rod can be neglected, the

energy per unit volume stored in the rod is

A2

2

2

Ee B

22

EeA C

2

Ee D

EeA



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6

20 The diagram below shows the process of expansion for a fixed mass of an ideal gas.

What is the ratiospeedsquaremeanrootinitial

speedsquaremeanrootfinal for the gas molecule?

A2

3 B

4

3 C

4

3 D

8

3

Ans: A

Therefore;

P/ 105Pa

Final state of as

Initial state of gas8

6

4

2

0 0.2 0.4 0.6 0.8V / m

3

2

3

1cnmpv

3

4

6.0102

2.01085

5

2

2

2

1

22

11

c

c

Vp

Vp

2

3

4

3

1

2

c

c



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7

21 In a mixture of two monatomic gases Y and Z at thermal equilibrium, the molecular mass

of Y is double the molecular mass of Z. The mean translational kinetic energy for Z is

8.2 x 10-21 J per molecule. The mean translational kinetic energy per molecule for Y is

A 4.1 x 10-21

J per molecule

B 5.5 x 10

-21

J per moleculeC 8.2 x 10

-21J per molecule

D 16.4 x 10-21J per molecule

Answer : C

Mean translational kinetic energy = kT2

3, that is independent of mass.

22 The figure below shows the isotherms for a fixed mass of an ideal gas at thermodynamic

temperatures T1and T2.

If T1is 273.15 K, the ice point, then the value T2is

A 91.05 K B 364.20 K C 364.21 K D 819.45 K

Answers

D

p

T1

3x T2

pV

x

nRTpV

1nRTx

23 nRTx

2

1

3 nRT

nRT

x

x

12 3TT



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8

23 Which of the following is true concerning the adiabatic expansion of an ideal gas?

A The internal energy of the gas increases

B The temperature of the gas does not change

C The r.m.s speed of the gas molecules decreases

D The external work done is more than the change in internal energy

24 The diagram shows a lagged metal rod of uniform cross section area. Two ends of the rod

are maintained at steady temperature of 1 and 2. The graph shows the variation of

temperature along the rod in a steady state.

Which of the following is true about the rate of heat flow through the rod,dt

dQ and the

thermal conductivity, kof the material with distance,xfrom the hot end?

dt

dQ k

A Decreases Unchanged

B Increases Unchanged

C Unchanged Decreases

D Unchanged Increases

x x x x x x x x x x

1 lagged

x x x x x x x x x x

rod

2

0

KT 15.2731

KKT 45.81915.27332



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9

25 Two properly insulated uniform rods, X and Y are arranged as shown in the figure

below.

The thermal conductivity of X is 10 times that of Y. The rods are in steady condition.

Which one of the following statement is correct?

A The rate of heat flow in X is greater than in Y.

B The temperature gradient along X is the same as that along Y.

C The temperatureat the interface between X and Y is nearly 0 C.

D The rate of heat flow will increase if the length of rod X is shortened but the

temperatures 0 C and 100 C of remain the same.

26 The graphs below are drawn to the same scale show the electric potential V between two

points P and Q. Which one shows that the electric field strength between P and Q is the

strongest?

C D

VV

OO QP P Q

0 C100 C

X Y

Thermal insulator C

50 mm 5 mm

A B

V

O QP

V

OQ

P



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10

27 A capacitor C is charged by using the circuit as shown in the figure below.

When switch S1is opened and then switch S2is closed, the reading of the galvanometer

G is

A zero

B not zero

C decreasing linearly with time until zero

D decreasing exponentially with time until zero

28 Which of the following statements explains correctly the decrease in resistivity of an

intrinsic semiconductor when its temperature increases?

A The drift velocity of the charge carriers increases with temperature.

B The number of charge carriers per volume increases with temperature.

C The rate of collision between the charge carriers and atoms increases with

temperature.

D The amplitude of vibrations of the atoms of a semiconductor increases with

temperature.

[Answer B: ,ne

Refer2

nm

E

and n increases as temperature

increases.

1/then is inversely proportional to ]

S2

S1

G

High resistance

-+C



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11

YX

4R

4R

R

E = 3.5 V

r= 1.5

29 When a potential difference Vis applied across a copper cable of length L and radius r,

the drift velocity of the electron is ve. If the length of the wireL changes, which of the

following graphs shows correctly the variation of vewithL?

[Answer C: I = Aneve = Ve/R thenL

ve1

reciprocal graph

occurs ]

30 An electric circuit is shown below.

If the potential difference across point X and point Y is 2.0 V, what is the value of R?

A 1.0 B 2.0 C 3.0 D 4.0

Answer: C For RRRRR

XY

XY

2so4

1

4

11

Therefore: )]([ VRRr

RV

XY

XYXY

A B

C D

ve

L

ve

L

LL

veve



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12

ohm3.0R

7)35.1(2)5.3)(35.1

2(2

RRR

R

31 A galvanometer with negligible internal resistance and a full scale deflection of 5 mA is

modified for use as a Voltmeter with a full scale deflection of 10V. The correct modification

for the required circuit is

A A resistor of 2 x 102is connected in series to the galvanometer

B A resistor of 2 x 103is connected in series to the galvanometer.

C A resistor of 2 x 104is connected in series to the galvanometer.

D A resistor of 2 x 105is connected in parallel to the galvanometer.

[ANSWER B: Galvanometer should connect in series with the resistor (Multiplier)

Rm

Use V = Vm+ Vg=I (Rm+Rg)

Rm= V/I - Rg= 10/0.005 0 = 2x103ohm ]

32 An electron is launched with velocity vinto a space which has magnetic flux densityB

and an electric field strength E that are perpendicular to each other. If the velocity vof the

electron is uniform, then

AB

Ev ; vis perpendicular toBandE

B

E

Bv ; vis perpendicular toBandE

CB

Ev ; vis perpendicular toB orE

DE

Bv ; vis perpendicular toBorE

[ANS: A Magnetic force = electric force

BeV = eE V = E/B ]



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13

33 The figure above shows two concentric rings X and Y are on the horizontal plane.

The radius of ring X is r1= 1.0 m and r2= 2.0 m. The current flows in ring Y is four times

the current in ring X but in the opposite direction. What is the resultant magnetic flux density

at the centre of the rings?

A Io5.1 and points towards N

B Io5.0 and points towards N

C Io

5.0 and points towards S

D Io5.1 and points towards S

[Answer B: Use: r

I

B 2

0

for wires X and Y;

Assuming: direction towards N = + and direction towards S = -

Resultant;

NtowardI0.5)1(2

2

)4

4

2o

o

111

I

r

I

r

I

r

IBBB ooo

YXT

X

Y

N

r1 r2

I

4I



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14

34 Figure (a) shows a rectangular coil PQRS placed in a uniform magnetic field. The

variation of the magnetic flux densityBwith time t is as shown in figure (b)

Which one of the following graphs shows variation of the magnitude of induced e.m.f. E

with time t ?

[ ANSWER A : Use e.m.f. E = - d/dt = -d(BA)/dt EdB/dt ]

4T3T2TT0

E

A

4T3T2TT0

E

B

4T3T2TT0

E

C

4T3T2TT0

E

D

t

B

T 2T 3T0 4T

X X X X

X X X X

X X X X

X X X X

Figure (b)Figure (a)

P Q

S R



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15

35 Which of the following produce voltage or current by self-induction?

A High voltage or current produced in a transformer

B High voltage produced in a Van de Graff generator

C High voltage produced when the switch in a solenoid circuit is opened

D Current flows in a copper plate when the plate is oscillating in a magnetic field

HINT : High voltage is produced when the switch of a solenoid circuit is turned on,in order to

oppose the collapse of the magnetic flux.

36 An alternating currentIrepresented by the equationI = 4 sin 100tflows in a resistor of

5.0 . IfI is in ampere and tin seconds, find the mean power dissipated in the resistor.

A 10 W B 20 W C 40 W D 160 W

HINT : I0=4 A,Mean power = I02R/2

Mean power = 40 W

37 The op-amp in the circuit shown contains a feedback resistorRf.

What is the function of the feedback?

A To increase the gain

B To oppose the input a.c.

C To increase the bandwidth

D To make the amplifier into non-inverting

38 Which of the following provides direct experimental evidence that light is a transverse

wave but not a longitudinal wave?

A Light can be polarized.

B Light can be diffracted.

C Two coherent light waves can be made to interfere.

D The intensity of light from a point source is inversely proportional to the square of

the distance from the source.

Rf

_

+

R



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16

39 A point object in air is at a distance u in front of a glass sphere of radius r. If the

refractive index of glass is n and the image formed inside the glass sphere is equal to 2u, what

is the value of u?

A rn

n

)2(

)1(2

B r

n

n

)2(2

)1(

C r

n

n

)1(2

)2(

D r

n

n)

2(

Answers : C

)1(2

)2(

1

2

2

1

2

1

n

rnu

r

n

u

n

r

n

u

n

u

40 Coherent monochromatic light illuminates two narrow parallel slits and the interference

pattern that results is observed on a screen some distance beyond the slits. Which

modification will increase the separation between the dark lines of the interference

pattern?

A Increase the distance between the slits

B Use monochromatic light of higher frequency

C Use monochromatic light of longer wavelength

D Decrease the distance between the screen and the slits

Solution: x =D/a, x increases when increases.

Answer: C

41 A monochromatic light of wavelength 600 nm illuminates a diffraction grating of 3 x 105

lines per metre. If the zero order is not being considered, how many diffracted fringes can be

observed?

A 2 B 5 C 7 D 10

Answer: D

5

6.5

)10600(90sin103

1

,...3,2,1,0,sin

9

5

m

m

xmx

mmd

o

Total no. of fringes = 10



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17

42 The graph below shows the results of the photoelectric effect in Milikans experiment.

The intercept of thef-axis of the graph atfodepends on

A the work function

B the stopping potential

C the intensity of radiation

D the frequency of radiation

HINT : W = h f0

43 The de Broglie wavelength of a bullet of mass 0.02 kg and moving at speed 300 ms-1is

A 7.3 10-36

m

B 1.8 10-35m

C 1.1 10-34

m

D 9.9 10-33m

44 Calculate the frequency of electromagnetic radiation emitted by a hydrogen atom which

undergoes a transition between energy levels of -1.36 x 10-19J and -5.45 x 10-19J.

A 1.36 x1014Hz

B 4.09 x 1014 Hz

C 6.17 x 1014 Hz

D 6.17 x 1019

Hz

45 The cut-off frequency in the continuous X-ray spectrum from an X-ray tube depends on

the

A target metal

B anode current

C filament current

D voltage across the tube



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18

46 The main principle used to produce laser is

A reflection of light

B radioactive decay

C stimulated emission of photons

D spontaneous emission of photons

47 The rest masses of deuteron , proton and neutron are 2.0150u, 1.0096u and 1.0097u

respectively. A deuteron may disintegrate to a proton and neutron if it

A emits a photon energy 3.1 MeV

B emits a photon of energy 2.0 MeV

C captures a photon of energy 2.0 MeV

D captures a photon of energy 4.1 MeV

48 A sample consists of two radioactive nuclides in equal proportion but each has a different

decay constant. Which graph shows the relation between the initial activity Aoand the initial

total number of radioactive nucleiNoof the sample?

49 Find the binding energy of carbon-12.

(mass of carbon-12 = 11.996706 u, mp= 1.007276 u, mn= 1.008665 u, u = 1.66 x 1027

kg)

A 0.511 MeVB 9.11 MeV

C 14.8 MeV

D 92.4 MeV

N0

Ao

Ao

A

D

N0

Ao

C

N0

Ao

B

N0



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19

50 Which of the following elementary particles has quark?

A Proton

B Photon

C Electron

D Neutrino



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CONFIDENTIAL* Marking scheme for PHYSICS STPM TRIAL 2010 NS

1



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2

SECTION A

Solution for question 1

tI [1]

I

t =2.0

102.0 = 10 rads

-1 [1]

Where, I = (10)(0.2)2

= 0.2 kgm2 [1]

10)10)(2.0(2

1

2

1energyKinetic 22 I J


(a) Applying Hookes law, F = ke ; 80 x 9.81 = k(5.0 x 10-2

) k= 1.57 x 104Nm-1 [1]

(b)


(a)

(b) A higher gradient around the equilibrium r= ro shows higher Young Modulus [1]

because high Young Modulus show higher force constant, which is representing by -dr

dF [1]

[ 1 ]

[1]61.0

1080

1057.1

2

1

[1]2

1

4

Hz

m

kf

Axes with either one label - [1]Shape of the graph for (i) [1]

Shape of the graph for (ii) [1]

(ii) Critically damped

(i) underdamped

time

Displacement

0

Shape of the graph for F-rgraph [1]

Shape of the graph for U-rgraph [1]



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3


(a) since cr.m.s. T 2

1

v

v=

1

2

T

T [1]

=

283

1132 [1]

= 2 OR ratio is 2:1 [1]

(b) Use PV = nRT RT

PVn [1]

=)283)(31.8(

)101)(102( 35 = 8.50 x 10

-2mol [1]



(a)Gain = -k

k

1

100= -100 [accept answer: 100] [ 1 ]

(b)

qE= Tsin 30o..(1)

mg=Tcos 30o(2) [ 1 ]

]1[Cx105.0

900)30)(tan81.9)(108.0(

[1]E

mgtan30q:Eq(2)Eq(1)

6-

3

0

o

0

Vi(V)

t

0

Vo(V)

t

-6

0.06

Since this is an inverting op-amp with gain 100, henceVo= -100Vi

-6 = -100 Vi

Vi= 0.06V

Saturation is said occured at 6V because volta e su lied is of 6V

Shape of the graph [1]

Label on 0.06V or calculation [11

Show saturation [1]

Arrows & labels 3 forces [ 3 ]

W

T

E30

0

F =eE



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4


(a)

)

1

20

1

)(158.1(

111

1

21

rrn

f

Focal length, f= - 34.5 cm

(b) Using

[1]5.34

11

30

1

111

v

fvu

v= -16.0 cm [1]

The image is 16.0cm from the lens on the same side as the object. [1]


(a) The energy required to break a nucleus apart into neutrons and protons, all infinitely far apart, and

this energy is divided by number of nucleon of the nucleus. OR

The binding energy of the nucleus divided by the total number of neutrons and protons making it up.

[ 1 ]

(b) Energy released = (Total binding energies of Xe-139 and Sr-95) Binding energy of U-235 [ 1 ]

= (8.39139)+(8.7495)(7.60235) [ 1 ]

= 210.51 MeV

211 MeV [ 1 ]

(c) The reaction that releases more energy (211 MeV) is more likely to occur. This is because the

more energy released, the more stable the daughter nuclei will be. [1]

A heavy nucleus undergoes fission such that its products will be more stable than the parent

nucleus. [1]

[ 1 ]

[ 1 ]



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5

SECTION BSolution for question 9

(a) (i) The gravitational force of attraction Fbetween two particles of masses m1and m2separated by

a distance of ris directly proportional to the product m1m2and inversely proportional to r2.[1]

This gravitational force which is force of attraction, acts along the line joining the two particles.

[1]

OR F-2

21

r

mmand symbols used are defined.

(ii) Gravitational force per unit mass

(iii) r is very large compared to radius of the planet, so planet behaves as a point mass.

(iv)

2

2

1

r

GM

mr

Mm

G

m

Fg

[1]

(v) radius of Earth is 1000 m [1] and22 )1000(

11

EERR

[1]

(b) (i)

(ii)From the equation3

22 4

RGM

T

y = mx + c

It is a straight line graph with gradient, m= 1.5

32

2

2

3

2

2

4

2

2

RGM

T

TR

GM

T

mRR

GMm

Hence, verified

Relationship or formulas with definition of symbols [1

Negative sign [1]

[1]

[1]

[1]

[1]

)4

log(2

1log

2

3log

)4

log(log3log2

)log()4

log()log(

2

2

32

2

GMRT

GMRT

RGM

T

[1]

[1]

[1][1]

From the graph given :

5.1

53.15.1013.12

5.60.9gradient



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6


(a) Two characteristics of standing waves :

Wave profile does not move

Energy is not transferred

There are nodes and antinodes

Points between a node and an antinodes have different amplitudes

Points between 2 successive nodes oscillate in phase with the same frequency

Choose any two [ 2 ]

(b) (i) Sound wave of a fixed frequency from the loud speaker travels into the tube and is reflected by the

water surface. [1]

The reflected wave has the same frequency and amplitude as the incident wave, but travels in the

opposite direction. [1]

Superposition between two waves produces standing waves. [1]

(ii) The column of air in the glass tube is forced into oscillation by sound waves from the loudspeaker.

Loud sounds are heard when there is resonance because the air column vibrates with a largest amplitude.When l = 9.6 cm, the air column is in the fundamental mode of vibration.

When l = 30.5 cm, the air column is in the first overtone. [4]

(b) (iii) 9.6 cm + e =4

and 30.5 cm + e =

4

3

(30.5 9.6) cm =2

=

f

v

2 =

)790(2

v [ 1 ]

Speed of sound, v = 2(790)(0.209) m s1= 330 m s

1 [ 1 ]

From 9.6 cm + e =4

, (

2

= 20.9 cm)

end correction, e =4

- 9.6 cm

= (10.45 9.6) cm [ 1 ]

= 0.85 cm [ 1 ]

(iv) When the temperature is higher, the speed of sound in air is higher, OR wavelength is longer. [ 1 ]

Hence the resonant lengths are larger. [1]


. (a) (i) Temperature gradient is the change of temperature per unit length of the conductor. [ 1 ]

(ii) Thermal conductivity is the rate of heat flow per unit cross-sectional area pertemperature gradient. OR [ 1 ]

k =

dx

dA

dt

dQ

where,dt

dQ= rate of heat flow; A= cross-sectional area;

dx

d= temperature gradient

[1]

[1]



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7

(b) (i)

Explanation :

dxd

1ty,conductiviThermal

k

hence material with higher k will have smaller temperature gradient [ 1 ]

(c) Use formula : Rate of heat energy,dt

dQ= - kA

dx

d= (0.15)(200)

31015

020

[ 1 ]

= 40 kW [ 1 ]

(i)Temperature of the board and insulating material interface, =)(

)(

2

2

1

1

2

22

1

11

kk

kk

[ formula - 1]

[ substitution - 1]

= 20oC [ final answer with correct unit 1 ]

(ii) New rate of heat energy,dt

dQ'= kA

dx

d=

)(

)( 21

ii

i

Ak

= 1.17 kW [ 1 ]

Shape of the graph [1]

different gradient [1]

[Curve shape to show different of

average gradient & label axis [2]]

[1]

[1]



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8


(a) Hall Effect The production of an e.m.f on a current-carrying conductor or semiconductor due to theapplication of magnetic field in a direction which is perpendicular to the direction of the current. [2]

(b) (i)

- The magnetic force Fmacts on electrons by the magnetic field will deflect electrons to the upper side of

the semiconductor whereas the lower surface of the semiconductor is induced positively. [1]

-This result in a potential difference Vbetween the two sides and an electric field occurs across QP. Thiselectric field will produce an electric force Fe acts on the electrons in the direction against the magnetic

force FBas shown in the diagram. [1]

- The magnitude of Fewill increase as the electric fieldEincreases due to more electrons deflected to the

upper side of the semiconductor. However ,this deflection process of electrons will stop when FB= Fe and

a steady p.d., VHwill produce across PQ.FB= Fe [1]

evB = eEBv = E

Substitute v = I/Aneand E= VH/d

net

BI

tdne

BId

neA

BId

d

V

Ane

IB H

H

H

V

dtAwhere)(

V)(

(ii) Metal has much more number of charges per volume, n than semiconductor. Since VHis inversely

proportional to naccording to the above equation, therefore the value of Hall voltage, VHproduced in

semiconductor is bigger and more obvious than in the metal. [2]

(iii) The pointer of the galnanometer will deflect to reverse direction or to the right hand side because the Hall

Effect will produce a reverse p.d across the PQ due to the magnetic force will deflect positive charge carriers(Holes) to the upper side of the semiconductor whereas the lower surface of the semiconductor is induced

negatively. [3]

(iv)

322

3193

3

H

106.6

)105.4)(1060.1)(105.10(

)10250)(0.2(BIn

nqt

BIV

m

qtVUse

H

v

FB=Beve

FE=eE

- - - - - - - - -

EVHd

t

P

Q

I

B

Diagram [1]

[1]

[1]

[1]

[1]



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9


(a) When an electron enters perpendicularly into a uniform magnetic field, the

electron will experience a magnetic force Fwhich is always at right angles to the

direction of the electron, as shown in the diagram. [1]

The electron will constantly change its direction of motion, so that a circularpath is formed. [1]

Magnetic force = Centripetal force

r

mvBev

2

[1] mBer

h

mv

h 11101.2 [1+1]

(b)(i) photon is a quantum of energy hf for electromagnetic radiation where his the Planck constant andf

is the frequency of the electromagnetic radiation. [1]

(ii) The de Broglies relationship gives the value of wavelengthp

h where his the Plancks constant.

[1]

(iii) The wave-particle duality refers to the wave nature of a particle under certain specific conditionsand the converse is also true. [1]

(c ) (i) 1. Electrons excited into higher energy levels. [1]2. When they fall back to lower energy levels, radiation / light (a photon) is emitted. [1]

3. The visible spectrum is caused by electron transitions among pairs of energy levels, emitting

radiation / photons with wavelengths in the visible region of the EM spectrum. [1]4. Line spectrum because only transitions between the defined / discrete levels occur. [1]

(ii)

m100.9

102.2)103)(1063.6(

)10x(-2.2-0

hcEORfcand

8

18834

18-

E

E

hfE

OR show usingdiagram - [2]

1

1

1



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

that is, photon. [ 1 ]

In the production of X-rays, electromagnetic radiation, that is photons, are emitted fromthe metal surface when the metal is hit by electrons. [ 1 ]

(b) (i) Continuous spectrum is produced when the electron bombarding the anode target experience

deceleration. [ 1]

Kinetic energy of the electron is changed into photon or radiated as

electromagnetic wave. [ 1 ]

The line spectrum is produced by transition of electron from higher energy

level to a lower energy orbit in the anode atom. [ 1 ]

The energy difference between the two orbits is radiate as a photon ofdiscrete wavelength. [ 1 ]

(ii) There is only one proton in the nucleus of a hydrogen atom. Therefore thedifference in energy level is small. [ 1 ]

This is not enough to produce photon energy needed for X-ray productionwhen transition of energy level occur. Hence, X-rays are not produced from

the hydrogen atom. [ 1 ]

(c) (i) Intensity Characteristic line

min wavelength

[ shape of graph = 1 ]

[ Characteristic lines andmin = 1 ]

(ii) [ 1 ]

min== [ 1 ]

= 4.14 x 10-12

m [ 1 ]

Documents

N9 STPM Trial 2010 Physics [w Ans] [B2D6F3EE] (1)