1984 Paper 2

Multiple-Choice Questions 1984 [1] If the engine of a rocket travelling in space is turned off, the rocket will A. stop moving B. continue to move with increasing velocity C. continue to move with decreasing velocity D. continue to move with uniform acceleration E. continue to move with uniform velocity [2] The graph below shows how the velocity of an object varies with time. velocity/ms-1

4 3 2 1 0 time/s 1 2 3 4

What is the distance travelled in the first 4 seconds ? A. 4 m B. 8 m C. 10 m D. 12 m E. 16 m [3] Which of the following velocity-time graphs correctly shows the motion of a ball falling freely in a vacuum ? A

0 C

B

v

v

h

v

0 D

v

h

0 E

h

0

h

v

0

h

[4] An object is attached to two stretched strings in a lift as shown in the diagram below.

T1 T2

When the lift accelerates upwards, how will the tensions in the 2 strings change ?

A. B. C. D. E.

Tension T1 Tension T2 increases increases increases decreases decreases increases decreases decreases no change no change

[5] A fat and a thin boy are playing on a see-saw as shown in the diagram.

Which of the following is true ? A. At any moment, the downward speed of the fat boy is speed of the thin boy. B. At any moment, the downward speed of the thin boy is speed of the fat boy.

greater than the upward greater than the upward

C. At any moment, the downward speed of the fat boy is equal to the upward speed of the thin boy. D. At any moment, the downward aqcceleration of the fat boy upward acceleration of the thin boy. E. At any moment, the downward acceleration of the thin boy is greater than the upward acceleration of the fat boy.

is greater than the

[6] A boy uses a frictionless and light pulley system as shown in the diagram to raise a load of 1000 N.

force

Load

The force required is A. 100 N D. 1000 N

B. 200 N E. 2000 N

C. 500 N

[7] A basketball falls freely from rest and hits the ground. It then rebounds to 1/4 of its original height. Neglecting air resistance, which of the following statements about the basketball is/are correct ? (1) Its kinetic energy just before collision is four times its kinetic energy just after collision. (2) Its potential energy just before collision is four times its potential energy just after collision. (3) The speed just before collision is two times the speed just after collision. A. (1) only D. (2) and (3) only

B. (2) only E. (1), (2) and (3)

C. (1) and (3) only

[8] A cannon ball is fired so that it hits the wall at the top of a 10 m tower. If the energy needed to destroy the wall is 49000 J and the mass of the cannon ball is 10 kg, the minimum initial velocity of the cannon ball required to break the tower wall is A. 100 m/s B. 200 m/s C. 300 m/s D. 400 m/s E. 500 m/s [9] A bullet hits a target at a speed of 200 m/s. If 50% of the kinetic energy has been converted into heat energy, what is the rise in temperature of the bullet ? (specific heat capacity of the bullet = 100 J/kg/K )

A. 10 K D. 200 K

B. 20 K E. 400 K

C. 100 K

[10] If an immersion heater takes 10 minutes to bring a cup of water to its boiling point of 100oC from the room temperature of 20xC, what will be the time taken for the boiling water to vaporize completely ? (specific heat capacity of water = 4200 J/kg/K , specific latent heat of steam = 2268 kJ/kg ) A. 33.75 minutes B. 54.00 minutes C. 67.50 minutes D. 75.40 minutes E. 87.40 minutes [11] A cooling curve for liquid naphthalene is shown below. Temperature/oC 80 B

C

70 60 Time/s

From the graph, which of the following statement(s) is/are true? (1) The melting point of naphthalene is around 70 oC (2) In the period BC, only liquid naphthalene is present (3) In the period BC, no energy is given by naphthalene to the surroundings. A. (1) only D. (2) and (3) only

B. (1) and (2) only E. (1), (2) and (3)

C. (1) and (3) only

[12] An immersion heater of resistance 50 ohms raises the temperature of 1 kg of water by 20 K in 3 minutes, the voltage supply being 200 V. What would be the energy wasted ? (specific heat capacity of water = 4200 J/kg/K) A. 0.44 kJ B. 2.32 kJ C. 44 kJ D. 60 kJ E. 81.6 kJ [13] An equal quantity of heat is supplied to each of the following substances and the corresponding rises in temperature are recorded. Which of the following substances has the smallest specific heat capacity ? Substance Mass (kg) Rise in temperature (K) A 2.0 5 B 2.5 5 C 3.0 4 D 4.5 3 E 5.0 3

[14] As shown in the diagram, a narrow parallel beam of light is converted to a wider parallel beam by placing two lenses L1 and L2 in the positions shown.

L1

L2

Which of the combinations below when correctly chosen and installed could produce the effect required ?

(1) (2) (3)

Lens L1 convex concave concave

A. (2) only D. (2) and (3) only

Lens L2 concave concave convex B. (3) only E. (1), (2) and (3)

C. (1) and (3) only

[15] The diagram represents the path of a ray of light passing from medium I to medium II and the ray is totally reflected at the boundary between media II and III. All boundaries are parallel. I

II

III

In which medium has light the (i) greatest, and (ii) least speed ?

A. B. C. D. E.

Greatest speed I I II III III

Least speed II III I I II

[16] A fish in a pond is observed by a boy standing at the edge. The line joining the actual position of the fish and the eye makes an angle of 45o with the water surface as shown.

45o

Q P

R S

T

The position of the image of the fish is probably at A. P B. Q D. S E. T

C. R

[17] Which of the following optical instruments would be most suitable for allowing the driver of a double-decker bus to observe conditions in the upper deck ? A

B

D

E

C

[18] Which of the follwoing will produce a diminished image of an object O ? (f is the focal length) A

A

O f

O f

f

C

f

D

O O f

f

f

f

E

O

f

f

[19] As shown in the diagram below, the apparent position of the aeroplane seen by the diver at the bottom of the small pond is at P Q R S T

A. P D. S

B. Q E. T

C. R

[20] As water is poured into a long glass cylinder, sound is heard. Which of the following is/are correct ? (1) The frequency of the sound gradually increases (2) The wavelength of the sound gradually increases. (3) The velocity of the sound gradually increases A. (1) only D. (1) and (3) only

B. (2) only E. (1), (2) and (3)

C. (3) only

[21] Two pulses A and B are generated on a string and are travelling towards each other as shown in the figure. Pulse A is greater in amplitude than pulse B. A

B

Which of the following will be the resulting waveform after they meet each other ? A

B

D C

E

standing wave

[22] In a ripple tank experiment, a series of plane water waves are sent through a narrow slit. Which of the following will have changed when the water waves emerge from the slit ? (1) wave speed (2) wave pattern (3) frequency A. (1) only D. (2) and (3) only

B. (2) only E. (1), (2) and (3)

C. (1) and (2) only

[23] As shown in the diagram below, two sound waves of the same frequency are emitted from 2 sources A and B. P B A

What kind of interference will occur at the mid-point when the 2 waves generated are (1) in phase; (2) out of phase ?

A. B. C. D. E.

In phase Out of phase constructive constructive constructive destructive destructive destructive destructive constructive cannot be determined cannot be determined

[24] Two uncharged metal spheres in contact are suspended by dry cotton threads. When a positively charged rod X is brought near them as shown in the diagram, the distribution of charges on the spheres will be

+

A

B

-

+-+-

D

C

- E

+

-

-++-

[25] Which of the following devices is designed to convert mechanical energy into electrical energy ? A. lead accumulator B. transformer C. thermocouple D. photocell E. dynamo

[26] As shown in the diagram, a 200 V mains supply is stepped down to 10 V by a transformer. 3A

200V

10V

If the output current is 3 A and the efficiency of the transformer is 75%, what is the current in the primary coil ? A. 0.1 A B. 0.2 A C. 0.3 A D. 0.4 A E. 0.5 A [27] Two heaters of rating 1 kW, 200 V and 2 kW, 200 V respectively are connected in series to a 200 V supply. What is the total power consumed by the heaters ? A. 3 kW B. 1.5 kW C. 2 kW D. 1 kW E. 0.67 kW [28] P and Q are two long parallel straight wires carrying currents as shown. What is the direction of the force on Q ?

P

A. to the left D. into this page

Q

B. to the right C. out of this page E. no force acts on Q

[29] A positively-charged rod is brought near to the cap of an uncharged electroscope with an earthed metal case as shown in the diagram. +++

Which of the following statements is/are correct ? (1) Electrons are attracted from the gold leaf to the metal cap (2) The inside of the metal case is negatively charged

(3) The divergence of the gold leaf will decrease when the joined by a metal wire A. (1) only D. (2) and (3) only

B. (2) only E. (1), (2) and (3)

cap and the metal case are

C. (1) and (3) only

[30] Which of the following has the greatest current when it is operated at 200 V ? A. a lamp with a resistance of 400 ohms B. a rice-cooker with rating of 400 W at 200 V C. an electric iron with rating of 400 W at 220 V D. a motor with a resistance of 200 ohms E. a hair-dryer with rating of 600 W at 200 W [31] As shown in the circuit, the lamp will light up when the switch is at position 1 2 3

A. 1 only D. 1 and 2 only

B. 2 only E. 1 and 3 only

C. 3 only

[32] The diagrams below show three possible arrangements of four (a)

identical resistors R.

(c)

X

Y

(b)

X

X

Y

Y

List the arrangements in order of increasing equivalent resistance, as measured between X and Y. A. (1), (b), (c)

B. (b), (c), (a) C. (c), (a), (b) D. (c), (b), (a) E. (b), (a), (c)

[33] Four identical bulbs P, Q, R and S are connected as shown in the two circuit diagrams below. constant voltage supply

constant voltage supply

P

R

Q

S

What happens to the brightness of P and R if the switches of both circuits are closed ?

A. B. C. D. E.

Brightness of P Brightness of R decreases remains constant remains constant decreases increases remains constant remains constant remains constant decreases decreases

[34] An ancient piece of wood was tested for its age by carbon 14 dating method. The normal emission rate from 2 g of carbon from a living plant is 20 counts per minute. If the rate from 2 g of carbon from the wood is 5 counts per minute, and the half life of carbon 14 is 5700 years, what is the approximate age of the wood in yearts ? (Background radiation may be neglected.) A. 5700 x 4 B. 5700 x 2 C. 5700 D. 5700/2 E. 5700/4 [35] In the figure below, S is a switch to turn on/off the electric fan. X, Y and Z are wires to be connected to the three terminals of a plug.

X S Y Z

How should X, Y and Z be connected to the three pins (Earth, Live and Neutral) of a given plug ? Earth

Live Neutral

A. B. C. D. E.

X Y Z X Y

Y X Y Z Z

Z Z X Y X

[36] X is a radioactive element which emits radiation as it decays. If all the radiation emitted is bent by a magnetic field in the direction shown below (going into paper), then the radiation consists of + + + + + + + + + + + + + + + + + + + + + +

original direction

+ X + + + + + + + + + + + + + + + + + + + + + + + + + + + + + +

Path after deflection

+ + + + + + + + + + +

A. alpha, beta and gamma rays B. alpha and gamma rays only C. beta and gamma rays only D. alpha rays only E. beta rays only [37] The diagram below represents the relative position of a line of particles along a stationary longitudinal wave at a certain instant.

12 3 4

5

6 7 8 9 10

11 12 1314 15 16

Which of the following statements is/are correct ? (1) Particle 5 has the greatest amplitude. (2) Particle 8 is momentarily at rest. (3) The distance between particle 4 and 10 is equal to one A. (1) only D. (2) and (3) only

B. (3) only E. (1), (2) and (3)

End of MC1984

wavelength.

C. (1) and (2) only