STPM TRIAL PHYSICS 2

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PEPERIKSAANPERCUBAANSETARASTPM

NEGERI SEMBILAN DARUL KHUSUS

TAHUN2011

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

Inst ructions to candidates:

A

A

nstver all questions in Section A in the spaces provided.

l/

working must be shown. For calculations, relevant

alues of constants in the Data Booklet must be used. For

v

n

a

umerical answers, units must be quoted wherever they are

rppropriate.

A

nswer any four questions ji·om Section

For this section,

w

e

a

b

rite your answer on the answer sheets provided. Begin

ach answer on a ji·esh sheet of paper, and arrange your

nswers in numerical order. Tie your answer sheets to this

ooklet.

nswer may

A

M. alaysia.

be written

A

Data booklet

provided.

in either English or Bahasa

For examiner's use

only

1

2

3

4

10

13

14

This question paper consists of 14 printed pages only.

Jabatan Pelajaran Negeri Sembilan 2011

STPM TRIAL 960/2

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

[Turn over CONFIDENTIAL*

For 960 PI-fYSICS - PAPER 1 AND PAPER 2

960 PHYSICS STPM

CONSTANT VALVES

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

Speed of light in free space

c =3.00x 10

ms-

Permeability of free space

flo

4n

1

o-

Hm-

Permittivity of free space

8 8 -

1

F

m

Magnitude of electronic charge

e

1.60

10-

C

Plank constant

h

=

6.63 x

10-

Js

Unified atomic mass constant

=

1.66

10-

kg

Rest mass of electron

me= 9.11

10-

kg

Rest mass of proton

=

1.67

x

1

o-

kg

Molar gas constant

Avogadro constant

Boltzmann constant

k

1.38

x

10.

JK-

Gravitational constant

G

=

6.67

1

Nnl

kg-

Acceleration of free fall

g=9.81 ms-

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

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

[Turn over

Section A [ 40 marks]

Answer

all

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.

C=aT-bT

where

T

a

b

(a) Determine the dimension of heat capacity,

C.

(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]

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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

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 _rn3)

[: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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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]

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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

7 (a) State two observations from experiment on photoelectric effect that cannot

be

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·'

(i) the half-life [2 marks]

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

J

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Section B [ 60 mark<]

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, (ii) the resultant force on the car, (iii) the acceleration of the car.

[2 mark<] [2 mark<] [1 mark]

(b) For the car, motion is impossible without friction, Discuss what is meant by ji-iction and the direction in which it acts on the car. In your answer, suggest another example where friction is useful. [3 mark<] (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 of72000 N acts for 0.25 s. Calculate the change in velocity of

(i) the car, [3 marks]

(ii) the truck. [2 marks]

(e) Suggest one way in which the conditions in (d) are unrealistic. [1 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

(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,.,=

(ii) Determine E.,w for the particle of mass 2.5 >>I

o-J

(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]

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

> ,

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.

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(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

(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]

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.1_{hat 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]

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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*

Question

13

(b)

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

[2

(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<c-.--(b) Calculate the binding enc:rgy per nucleon for

(i)

(ii)

. 2"8(mU) -I uran1um- .J ₉₂ nuc eus,

!2

carbon-12 ( ₆ C) nucleus.

S'"! 'l':\T TRIAL qGo/'2

End

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Question

13

(b)

(ii)

'Nbat is the effect of using a metal target ofhigherltlomie nmnbd.

[2

(b)

(ii)

What is the effect of increasing the filament current to the continuous and characteristic

X-ray spectra?

[2

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

nucleus,

(ii) carbon-12

nucleus.

End

STPM TRlAL 960/2

*This paper is CONFIDENTIAL until the examination is over.

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