2010 YJC H2 Phy Paper1 Qn Ans

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Candidate’s Name ………………………………….……… CTG ……………….…

YISHUN JUNIOR COLLEGEJC 2 Preliminary Examinations 2010

PHYSICS 9745,9646/1HIGHER 2

27 August 2010

Paper 1 Multiple Choice Friday1 hour 15 minutes

Additional Materials:Optical Mark Sheet

INSTRUCTIONS TO CANDIDATES

Do not open this booklet until you are told to do so.

Write your name and CTG on the Optical Mark Sheet in the spaces provided.

Shade your CTG and Register Number in the space provided.

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

Read the instructions on the Optical Mark Sheet carefully.

INFORMATION FOR CANDIDATES

Each correct answer will score one mark. A mark will not be deducted for a wrong answer.

Any rough working should be done in this booklet.

This question paper consists of 20 printed pages.

Data

speed of light in free space, c = 3.00 108 m s–1

permeability of free space, o = 4 10–7 H m–1

permittivity of free space, o = 8.85 10–12 F m–1

(1/(36)) 10–9 F m–1

elementary charge, e = 1.60 10–19 C the Planck constant, h = 6.63 10–34 J sunified atomic mass constant, u = 1.66 10–27 kgrest mass of electron, me = 9.11 10–31 kgrest mass of proton, mp = 1.67 10–27 kgmolar gas constant, R = 8.31 J K–1 mol–1

the Avogadro constant, NA = 6.02 1023 mol–1

the Boltzmann constant, k = 1.38 10–23 J K–1

gravitational constant, G = 6.67 10–11 N m2 kg–2

acceleration of free fall, g = 9.81 m s–2

Formulae

uniformly accelerated motion, s = ut + at2

v2 = u2 + 2aswork done on/by a gas, W = p Vhydrostatic pressure, p = g hgravitational potential,

Displacement of particle in s.h.m. x = xo sin tvelocity of particle in s.h.m., v = vo cos t

=

resistors in series, R = R1 + R2+……….resistors in parallel,

electric potential,

alternating current/voltage, x = xo sin ttransmission coefficient T = exp(2kd)

where k =

radioactive decay, x = xo exp(–t)

decay constant, =

9745,9646/1/JC2Prelims/YJC2010

2

=

=

V =

1 What are the base units of specific latent heat of fusion?

A m2 s-2

B kg-1 m2 s2

C m2 s2 K-1

D kg-1 m2 s2 K-1

2 The residents of a certain town would like the passenger train service that passes through the town to make an additional stop at their station.

Graph A (in solid line) shows the time variation of the speed of a train that stops at the station whereas graph B (in dotted line) is for one that does not stop.

The total delay in making this additional stop is

A 320.0 sB 220.0 sC 190.0 sD 120.0 s


Speed / m s1

Time / s

Graph B

Graph A

70.0 190.0 320.0

50.0

0

train just arrives

train leaves

3

3 The time variation of the acceleration of an object is as shown in the graph below.

At which point is the velocity the greatest?

4 The figure below shows the path of a ball leaving the ground at point X and about to hit the ground at point Z.

If air resistance is negligible, the vertical component of

A velocity is maximum at YB displacement is minimum at YC velocity is the same at X and ZD acceleration is the same at Y as at Z


initial velocity

X

Y

Zground

A

B

C

Dtime

acceleration

4

5 A paratrooper jumps down from an aircraft and falls without significant drag force for 3 s before opening his parachute.Which of the following best shows the time t variation of his vertical acceleration a?


a

t/s

A

3

a

t/s

B

3

a

t/s

C

3

a

t/s

D

3

5

6 A trolley X of total mass 0.50 kg and speed 6.0 m s1 approaches, head-on, another trolley Y of total mass 0.60 kg and speed 5.0 m s1 moving in the same direction along a level track. The collision is elastic with each trolley having a magnet with the like poles facing each other as shown below.

At some instant during the collision, X is at rest. The speed of Y then is

A 3.0 m s1

B 5.0 m s1

C 6.0 m s1

D 10 m s1

7 A uniform horizontal beam is acted upon by an upward push force, as shown below, whose magnitude is equal to its weight.

The ends of the beam fit into sockets X and Y of two rigid vertical walls which keep the beam stationary.

Which of the following correctly states the directions of the forces acting on the beam at X and Y?

Socket X Socket Y

A downwards upwards

B upwards upwards

C downwards downwards

D upwards downwards

8 Two rigid beams, 1 and 2, are fixed to a vertical wall. A stationary load of weight W is hung from point X where the two beams are joined as shown.


weight

push

X Y

wall wall

X

6.0 m s1

Y

5.0 m s1

N S S N

6

Which diagram shows the forces acting at X?


W

Beam 1

Beam 2

X

Force in Beam 1

Force in Beam 2

W

A

Force in Beam 1

Force in Beam 2

W

B

Force in Beam 1

Force in Beam 2

W

C

Force in Beam 1

Force in Beam 2

W

D

7

9 The base area of a barge is 80 m2 and the sides of the barge are vertical. The depth h to which it rests in fresh water of density 1.0 103 kg m3 is as shown on the left figure.

When further loaded, as shown on the right figure, with 5.0 103 kg of cargo, the extra depth h to which the barge will rest is

A 0.063 mB 0.0064 mC 5.0 mD 610 m

10 A car of mass 1000 kg, traveling at 20 m s1 on a level road comes to rest in a distance of 25 m. What is the work done against friction?

A 0.50 kJ B 8.0 kJC 200 kJD 250 kJ


After

barge

h

80 m2

Before

h

8

11 A ball of mass m and speed v, rolls up a slope from P to Q, a horizontal distance d away as shown. The distance PQ measured vertically is r and along the slope is s . What is the work done against the weight during the journey?

A mgs B mgrC mgdD mg

12 A car moves around a horizontal circular track at a constant angular speed ω.

Which of the following statements is true about the car’s motion?

A Its linear velocity is constantB Its linear velocity is changingC Its linear acceleration is zeroD Its linear acceleration is constant


ωCar

Top view

P sr

Q

d

9

13 A race car moves at a high speed along a banked circular track, as shown below.

Which of the followings best represents the free-body diagram of the race car?

A B

C D

14 Planet X of mass M and planet Y of mass 3M revolve around a common centre. The two planets are constantly separated by a distance of D.

Where is this common centre of their rotation?

A from planet X

B from planet Y

C from planet X

D from planet Y


Side view

Centre of circular motion

Race car

10

15 A spring oscillates with a period of 1.0 s at a place where the acceleration of free fall is g. If it were to oscillate in another place where the acceleration of free fall is 2g, what would be the value of its new period?

A 0.5 sB 0.7 sC 1.0 sD 2.0 s

16 A particle P performs simple harmonic motion between points X and Y which are 4.0 cm apart . The time taken to move from X to Y is 0.8 s. What is the maximum speed of particle P?

A 5.0 x 102 m s1

B 8.0 x 102 m s1

C 16 x 102 m s1

D 34 x 102 m s1

17 Which one of the following is essential for the equation pV = nRT to be obeyed by a real gas?

A Changes should be at constant temperatureB Changes should take place at constant volumeC Pressures should be lowD Temperatures must be higher than 273.15 K

18 Two coherent waves of intensities I and amplitude Y, meet in phase at a point. Calculate, in terms of I and Y, the intensity and amplitude of the resultant wave at that point.

Intensity Amplitude

A 0 0

B I Y

C 2 I 2Y

D 4 I 2Y


11

19 Coherent monochromatic light illuminates two narrow parallel slits and the interference pattern which results is observed on a screen some distance beyond the slits. Which of the following will not affect the fringe separation of the interference pattern?

A Using monochromatic light of higher frequency B Increasing the distance between the screen and the slitsC Increasing the width of each slitD Increasing the distance between the slits

20 A thin copper rod is clamped at one end and made to vibrate by a driving force of variable frequency applied to the free end. At specific frequencies, it is found that the rod resonates. Which of the following diagram is incorrect, where N and A represent a nodal and antinodal position respectively?

A

B

C

D


clamp

N A

clamp

N A N A N A

clamp

N A N A

clamp

N A N

12

21 Which of the following statements about an electric field is incorrect?

A The electric field strength due to a point charge proportionately with 1/r2

where r is the distance from the charge.

B The electric field strength at a point is a measure of the force exerted on a unit positive charge at that point.

C The negative sign in the formula , implies that the field points in

the direction of decreasing potential.

D The electric field strength at a point is equal to the potential gradient at that point.

22 A point charge is placed at a point Y in front of an earthed metal sheet X. P and Q are two points between X and Y as shown in the diagram. Which of the following mathematical relations between the electric field strengths E at different points is correct?

A EP = EQ

B EP = 0C EP EQ

D EP < EQ

23 A 10 Ω resistor is connected across a cell of e.m.f 6.0 V and internal resistance 2.0 Ω. How much heat energy is dissipated by the resistor when 2 C of charge flows through it?

A 2.0 JB 10 JC 12 JD 40 J


P Q Y

X

point charge

13

24 Five identical resistors of resistance 2.0 Ω are connected as shown below.

If the resistor R in the middle is removed from the circuit, what is the change in the effective resistance across PQ?

A Increase by 0.1 Ω B Increase by 0.4 ΩC Decrease by 0.4 ΩD Decrease by 2.0 Ω

25 In the circuit below, four resistors are connected in series with a 12 V battery. One point along the circuit is earthed as indicated.

What is the potential at point Z?

A − 5.3 VB − 8.6 VC + 3.3 VD + 5.3 V


R

R

R

R

R

P Q

12 V

2.5 Ω 3.0 Ω 1.0 Ω 2.5 Ω

Point Z

14

26 Four identical bulbs labeled 1 to 4 are connected with a cell E in the circuit shown below.

Which of the followings will increase the brightness of bulb 1?

A Replace the cell E with another cell of lower e.m.fB Remove bulb 2C Connect another bulb in parallel with bulb 2D Connect another bulb in series with bulb 4

27 A thermistor is connected in series with a fixed resistor of resistance R and a cell of e.m.f 10 V, as shown in the diagram below.

When the temperature of thermistor is 20°C, its resistance is 5.3 Ω and the potential difference VT across it is 4.5 V.

What is the value of VT if the temperature of thermistor increases to 60°C and the resistance drops to 3.1 Ω?

A 1.5 VB 2.6 VC 3.2 VD 3.5 V


1

2

3

4

E

R

VT

10 V

15

28 Two identical magnets A and B are dropped from rest through the middle of a conducting ring. The ring for B has a small break in it as shown. Which of the following statements is correct?

A Magnet A has a smaller acceleration.B Magnet B has a smaller acceleration.C Both magnets fall through with the same accelerationD Both magnets fall through at constant velocity.

29 A rectangular coil with 200 turns has dimensions 5.0 cm by 4.0 cm. When the coil is placed in a magnetic field B of 0.35 T and the current, I in the coil is 1.6 A, what is the value and direction of the maximum torque?

A 0.22 N m with the left edge moving into plane of paperB 5.6 N m with right edge moving into plane of paperC 0.22 N m with right edge moving into plane of paperD 11.2 N m with left edge moving into plane of paper


N

S

Magnet A

N

S

Magnet B

4.0 cm

I = 1.6 A5.0 cm

B = 0.35 T

16

30 The figure below shows the circuit diagram for a half-wave rectifier. The supply to the rectifier is rated as 50 Hz , 6.0 V r.m.s. What is the average power dissipated in the load resistor, R = 2.0 Ω.

A 9.0 WB 18 WC 25 WD 36 W

31 Transitions between the lowest three energy levels in a particular atom give rise to three spectral lines of wavelength, in order of increasing magnitude, 1, 2 and 3. Which of the following correctly relates 1, 2 and 3?

A 1 + 2 = 3

B 1 = 2 + 3

C

D

32 White light from a hot source is passed through sodium vapour and viewed through a diffraction grating.

Which of the following best describes the spectrum seen?

A Dark lines on a white backgroundB Coloured lines on a white backgroundC Coloured lines on a dark backgroundD Dark lines on a coloured background


50 Hz6.0 Vr.m.s

R

17

33 A beam of electrons are accelerated to hit a metal target and the corresponding X-ray spectrum is as shown below.

Which of the following statements is true of the features of the spectrum?

A Increasing the accelerating voltage increases 1

B Changing the type of metal changes 1

C Both I2 and 2 decrease when the electron beam is made less intenseD I3 includes the number of X-ray photons of wavelength 3 emitted by the

‘braking radiation’ process.

34 The uncertainty in the de Broglie wavelength of an electron was found to be 1 1010 m. Its uncertainty in position is thus

A 1 109 m B 1 1010 mC 8 1012 mD 5 1045 m

35 In terms of band theory, which of the following is one of the main features which explains the electrical properties of intrinsic semiconductors?

A More valence electrons B Smaller energy band gapC More holes D More energy levels

36 Which of the following terms is not applicable to photons produced by stimulated emission?

A Coherent B ParallelC In Phase D Polarised

37 Which of the following is true about extrinsic semiconductors?


Intensity

Wavelength01 2 3

I3

I2

18

A Extrinsic semiconductors can only be made by doping silicon with either arsenic or boron.

B p-type extrinsic semiconductors are positively charged.C Extrinsic semiconductors have higher conductivity compared to intrinsic

semiconductors.D Extrinsic semiconductors have larger energy band gaps compared to

intrinsic semiconductors.

38 For the same given p-n junction, which circuit below gives the widest depletion region?

A

B

C

D


p n

p n

p n

p n

19

39 A Thorium-234 nucleus decays and undergoes two beta-particle emissions, one alpha-particle emission and one unknown emission to form the Radium-226 nucleus.

What could be the unknown emission?

A Alpha-particle emissionB Beta-particle emissionC Gamma emissionD Neutron emission

40 A stationary uranium nucleus, undergoes radioactive decay with emission

of a helium nucleus, of kinetic energy E. What is the kinetic energy of the daughter nucleus?

A

B

C E

D

End Of Paper

Answers to Paper 1 of Preliminary H2 Physics Exam 2010


20

1 A 11 B 21 D 31 C

2 B 12 B 22 D 32 D3 B 13 B 23 B 33 D4 D 14 D 24 A 34 C5 A 15 B 25 A 35 B6 D 16 B 26 C 36 D7 A 17 C 27 C 37 C8 C 18 D 28 A 38 D9 A 19 C 29 C 39 A10 C 20 B 30 A 40 A


21

2010 YJC H2 Phy Paper1 Qn Ans

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