pjc phy h2 mid-year paper 1

7/30/2019 PJC PHY H2 Mid-Year Paper 1

1/18

2012/PJC/PHYSICS/9646 [Turn over

This document consists of18 printed pages.

PIONEER JUNIOR COLLEGEJC2 Mid-Year Examination

PHYSICS 9646/01Higher 2

Paper 1 Multiple Choice4 July 2012

1 hour 15 minutes

Additional Material: Multiple Choice Answer Sheet

READ THESE INSTRUCTIONS FIRST

Write in soft pencil.Do not use staples, paper clips, highlighters, glue or correction fluid.Write your name, class and index number on the Answer Sheet in the spaces provided.

There are forty questions on this paper. Answerall questions. For each question thereare four possible answers A, B, C and D.Choose the one you consider correct and record your choice in soft pencil on theseparate Answer Sheet.

Read the instructions on the Answer Sheet very carefully.

Each correct answer will score one mark. A mark will not be deducted for a wronganswer.Any rough working should be done in this booklet.


2/18

2

2012/PJC/PHYSICS/9646

Data

speed of light in free space, 81000.3 c ms1

permeability of free space, 70 104 Hm1

permittivity of free space, 120 1085.8 Fm1

910361 Fm1

elementary charge, 191060.1 e C

the Planck constant, 341063.6 h Js

unified atomic mass constant, 271066.1 u kg

rest mass of electron, 311011.9 em kg

rest mass of proton, 271067.1 pm kg

molar gas constant, 31.8R JK1 mol1

the Avogadro constant, 231002.6 AN mol1

the Boltzmann constant, 231038.1 k JK1

gravitational constant, 111067.6 G Nm2kg2

acceleration of free fall, 81.9g ms2


3/18

3


Formulae

uniformly accelerated motion, 2

2

1atuts

asuv 222

work done on/by a gas, VpW

hydrostatic pressure, ghp

gravitational potential,r

Gm

displacement of particle in s.h.m., txx sin0

velocity of particle in s.h.m., tvv cos0

22

0 xx

mean kinetic energy of a molecule kTE2

3

of an ideal gas,

resistors in series, ...21 RRR

resistors in parallel, .../1/1/1 21 RRR

electric potential,r

QV

04

alternating current/voltage, txx sin0

transmission coefficient, kdT 2exp where

2

28

h

EUmk

radioactive decay, )exp(0 txx

decay constant,

2

1

693.0

t


4/18

4


1 The manufacturers of a digital voltmeter give, as its specification, accuracy 1% with anadditional uncertainty of 10 mV. The meter reads 4.072 V.

How should this reading be recorded, together with its uncertainty?

A (4.07 0.01) V

B (4.07 0.04) V

C (4.07 0.052) V

D (4.07 0.05) V

2 A radio aerial of length L, when the current is I, emits a signal of wavelength and

powerP. These quantities are related by2

2 L

P k

I

where kis a constant.

What unit, if any, should be used for the constant k?

A no unit

B volt

C watt

D ohm

3 Two cars are 24.0 m apart and travelling towards each other. The speeds of car A andcar B are 9.0 ms1 and 12.0 ms1 respectively when driver A realises that a collision withcar B is imminent. Driver A applies the brake immediately and the car decelerates with4.5 ms2.

The minimum deceleration of car B if the collision is to be avoided is

A 4.5 ms2.

B 4.8 ms2.

C 6.0 ms2.

D 8.0 ms2.


5/18

5


4 A body is at rest at time t= 0 and moves with constant acceleration.

Which of the following graphs best represents the variation with time tof displacement sof the body?

A B

C D

5 An aircraft in level flight is moving with constant velocity relative to the ground.

The resultant force acting on the aircraft is equal to

A the weight of the aircraft.

B the resultant of the air resistance and the thrust of the engines.

C the resultant of the air resistance and the weight of the aircraft.

D zero.

6 A crane has a maximum safe working load of 41.2 10 N and is used to lift a concreteblock of mass 1000 kg.

What is the maximum safe upward acceleration of the block while being lifted?

A 0.83 ms2

B 1.1 ms2

C 1.2 ms2

D 2.2 ms2

t

s

0

0

t

s

00

t

s

00

t

s

0

0


6/18

6


7 A heavy uniform plank of length L is supported by two forces1F and

2F at points of

distances4

Land

8

Lfrom its end as shown in the diagram.

What is the ratio2

F :1F ?

A 1:3

B 2:3

C 3:2

D 3:8

8 A spring that obeys Hookes law is of length x1 when it is in equilibrium under a tension

T1. Its length becomesx2 when the tension is increased to T2.

What is the extra energy stored in the spring as a result of this process?

A1

4( T2 + T1 )(x2 x1)

B1

4( T2+ T1)( x2 + x1)

C1

2( T2 + T1)( x2 x1 )

D1

2( T2 + T1 )( x2 + x1 )

4

L

8

L

L

1F

2F


7/18

7


9 A block, made up of 2 different materials, floats horizontally in a liquid as shown in thediagram below.

What is the weight of the block given that the density of material 1, material 2 and theliquid is 1, 2 and 3 respectively?

A3LBH g

B 22

LBHg

C 1 32

LBHg

D 32

LBHg

10 The driving force Fof a car of mass m causes the car to accelerate. In a time tit travelsa distance s and its speed increases from u to v.

What is the useful power output by the car engine?

AFs

t

B ( )m v u

C Ft

D2 2( )

2

m v u

t

liquid surface

Front Viewmaterial 2

material 1

B

H

2

H

2

L

H

2


8/18

8


11 A body of mass 2.0 kg is acted on by a force which varies with distance moved by massas shown below.

If the force acts on the mass where its initial velocity is 3.0 m s1, what is its final velocityassuming friction is negligible?

A 4.5 ms1

B 4.8 ms1

C 5.4 ms1

D 10.0 ms1

12 Which of the following statements is incorrect for a particle moving in a horizontal circlewith constant angular velocity?

A The kinetic energy is constant but the velocity varies.

B The speed and the linear momentum are both constant.

C The centripetal force is not constant.

D The kinetic energy is constant but the linear momentum varies.

13 A 0.150 kg ball on the end of a 1.10 m inextensible cord (negligible mass) is swung in avertical circle.

What is the tension in the cord at the lowest point if the ball moves at 6.60 ms1 at thispoint?

A 4.47 N

B 5.94 N

C 7.41 N

D 13.2 N

distance / m0

1 2 3 4

5

3

force / N


9/18

9


14 A and B are two points at distance R from centre O of a planet while C and D are atdistance 2Raway from O.

Which one of the following statements is not correct?

A Points A and B are of equal gravitational potential.

B The work done on a mass as it moves from C to D is zero.

C Positive work has to be done on a mass when it moves from Dto A.

DGravitational potential at D 1

2Gravitational potential at B

15 A rocket is orbiting around the Earth with a tangential velocity of v. The orbit has agravitational potential of 20 MJ kg1. The boosters are fired and the rocket moves to anew orbit of gravitational potential 10 MJ kg1.

What is the velocity of the rocket in the new orbit?

A2

v

B4

2v

C 102 v

D2

v

A

O

D

B

C R

2R


10/18

10


16 An object placed on a horizontal platform is vibrating vertically in simple harmonic motionwith a frequency of 2.0 Hz.

The maximum amplitude of oscillation that will allow the object to remain in contact withthe platform throughout the motion is

A 0.78 cm.

B 1.6 cm.

C 2.5 cm.

D 6.2 cm.

17 The diagram shows the graph of displacement against time for a body performing simpleharmonic motion.

At which point, A, B, C or D is the body travelling and accelerating in the oppositedirection?

18 An ideal gas undergoes an expansion in volume from 41.3 10 m3 to 43.6 10 m3 at a

constant pressure of 51.3 10 Pa. During this expansion, 24 J of heat is supplied to gas.

What is the overall change in internal energy of the gas?

A decrease of 54 J

B decrease of 6 J

C increase of 6 J

D increase of 54 J

time

displacement

0

AB

C

D


11/18

11


19 Two objects X and Y are made of the same material. Object X has a greater mass thanobject Y. Both objects are at the same temperature.

Which of the following correctly compares the mean kinetic energy and the total energyof the molecules in the objects?

mean kinetic energyof the molecules in X and Y

total energyof the molecules in X and Y

A same greater in X than in Y

B same less in X than in Y

C greater in X than in Y same

D less in X than in Y same

20 The figure below shows different regions of air for a progressive sound wave moving tothe right. At a certain instant. P, Q, R, S and T are particles at the centres of theseregions.

Which of the following statement is true?

A R is moving towards the right at that instant.

B The distance between P and T is one wavelength.

C The amplitude of R is always zero.

D After a period of time, Q moves to the position of S.

21 The wavelengths of a radio wave and that of an ultraviolet ray are in the ratio 10m : 1.

Which of the following is a possible value form?.

A +15 B +9 C 9 D 15

22 A tall vertical cylinder is filled with water and a tuning fork vibrating at 400 Hz is held overits open top. The water is slowly run out and the first resonance of the air column isheard when the water level is 0.21 m below the top of the cylinder.

Neglecting end corrections, how far from the top will the water level be when the nextresonance is heard?

A 0.32 m B 0.42 m C 0.63 m D 0.84 m

P Q R S T


12/18

12


23 S1 and S2 are two identical, small loud-speakers 0.50 m apart and connected to thesame audio frequency generator. They vibrate in phase, producing sound waves ofwavelength 0.40 m.

A microphone located at point P detects a minimum in the pattern of superposition.

If P is 12.00 m from S2 and PS1 > PS2, then the least possible distance of P from S1 is

A 12.15 m.

B 12.20 m.

C 12.40 m.

D 12.50 m.

24 Which one of the following graphs correctly shows how the electric field and potentialvary with distance from a negative point chargeQ?

A B

C D

r

E

V

r

E

V

rE

V

r

E

V

S1

S2P


13/18

13


25 The figure below shows two parallel metal plates AB and CD in an evacuated enclosure.CD is maintained at a positive potential Vrelative to AB. Electrons of velocity venter thespace between the plates as shown in the figure.

Given that the electron charge is e and the electron mass is em , the electrons will just

reach AB if

Ad

evm

o

e42

1 2

B eVvme 2

2

1

C eVcosvme 2

2

1

D eVsinvme 2

2

1

26 The current in a metallic conductor increases when the potential difference appliedacross it is increased.

Which of the following best explains this?

A There is less chance of a charge carrier striking an atom.

B The mean time between collisions decreases.

C The acceleration of the charge carriers increases.

D The rise in temperature increases the thermal motion of the charge carriers.

v

d

A B

C D


14/18

14


27 In the diagram below, the variable resistorRcan be adjusted over its full range from zero

to 107.

What are the approximate limits for the resistance between P and Q?

A 10 and 104

B 10 and 107

C 10 and 1011

D 104 and 107

28 A dry cell of e.m.f. 1.5 V and internal resistance 0.75 maintains a steady current of

0.5 A in the external circuit.

Which of the following statements is true about the energy in the circuit when anelectrical charge of 3 C flows through the external circuit?

A The total energy expended is 1.0 J.

B The chemical energy supplied by the cell is 2.0 J.

C The thermal energy generated in the external circuit is 2.4 J.

D The electrical energy expended in the external circuit is 3.4 J.

RP Q

104

10 0 to 107


15/18

15


29 Two cells of e.m.f. E1 and E2 and of negligible internal resistances are connected withtwo variable resistors as shown in the diagram below. When the galvanometer shows nodeflection, the values of the resistances are Pand Q.

What is the value of the ratio 2

1

E

E

?

AP

Q B

( )

P

P Q C

( )

Q

P Q D

( )P Q

P

30 A horizontal power cable of length 2.0 m carries a steady current of 3.0 A into the planeof the diagram.

What is the force acting on the cable that is caused by the Earths magnetic field of flux

density 54.0 10 T, in a region where this field is at 65 to the horizontal?

A 82 N B 220 N C 240 N D 660 N

31 An electron moves in a circular orbit in a uniform magnetic field.

Which of the following statements is correct?

A The period of the orbit is independent of the speed of the electron.

B The momentum of the electron is independent on its charge.

C The radius of the orbit is directly proportional to its charge.

D The magnetic force on the electron is dependent on the mass of the electron.

65

I

Earths magnetic field

E1

E2

P Q


16/18

16


32 A circular coil has resistance Rand areaA. The coil is placed in a uniform magnetic fieldof strength B such that its plane is perpendicular to the magnetic field lines.

The plane of the coil is now rotated through 90about the axis PQ.

The magnitude of the charge that flows in the coil is

AR

BA.

BBA

R.

C BAR.

D zero.

33 A horizontal straight wire of length 20 m is raised vertically through a height of 3.0 m in0.20 s. The horizontal component of the Earths magnetic field strength perpendicular to

the wire is 52.0 10 T.

What is the average e.m.f. induced across the ends of the wire?

A zero B 0.24 mV C 1.2 mV D 6.0 mV

34 Half-wave rectification of an alternating sinusoidal voltage of amplitude 100 V gives thewaveform shown in the figure below.

The r.m.s. value of the rectified voltage is

A 25.0 V. B 50.0 V. C 70.7 V. D 100 V.

100

V/ V

t/ s0

Q

P

x x x x x

x x x x x

x x x x x

x x x x x


17/18

17


35 A generator produces a current of 60 A r.m.s. at a voltage of 120 V r.m.s. The voltage isstepped up to 4500 V r.m.s. by an ideal transformer and transmitted through a power line

of total resistance 1.0 .

What is the percentage power lost in the transmission line?

A 0.018%

B 0.024%

C 0.036%

D 0.048%

36 In order to produce X-rays of wavelength 0.200 nm, what is the minimum potentialdifference through which the electron in an X-ray tube must be accelerated?

A 5.22 kV

B 6.22 kV

C 7.22 kV

D 8.22 kV

37 Electrons of energy 6.0 eV are incident on a potential barrier of height 7.5 eV and

thickness 0.60 nm, at a rate of 221.25 10 electrons per second.

What will be the average waiting time for an electron to be transmitted?

A 191.48 10 s

B 192.48 10 s

C 193.48 10 s

D 181.48 10 s

38 Why is laser light monochromatic?

A The excited electrons are in a metastable state.

B The system is in a state of population inversion.

C The emitted photon and the incident photon are of the same phase.

D Photons of the same energy as that of the incident photons are emitted when theelectrons transit down from a higher energy level.


18/18

18

39 Energy levels in low-pressure gases are represented as lines whereas in solids, thelevels are shown as bands.

What is responsible for the formation of bands?

A Atoms in solids are much closer together than those in gases.

B Atoms in solids are much denser than those in gases.

C Solids are better electrical conductors than gases.

D Solids are not fluids but gases are fluids.

40 In a p-n junction, free electrons near the junction in the n-type material diffuse across thejunction into the p-type material.

Diffusion occurs because

A the concentration of electrons in n-type material is small and in p-type material islarge.

B the concentration of electrons in n-type material is large and in p-type material issmall.

C the small potential across the depletion layer cause electrons to diffuse continuouslyacross the p-n junction.

D of different thermal agitation of atoms in the n-type and p-type material.

End of paper

pjc phy h2 mid-year paper 1

Documents