1983 Paper 2

Multiple-Choice Questions 1983 When necessary, take g = 10 m/s2. [1] A person in a lift, which is ascending at a velocity of 10 m/s, releases a ball. What is the velocity of the ball with respect to the earth at the moment when the ball is released ? A. 0 m/s B. 10 m/s upwards C. 10 m/s downwards D. 20 m/s upwards E. 20 m/s downwards [2] Two balls X and Y, of the same mass, are released from rest simultaneously at A. X falls vertically downwards while Y runs downwards along the smooth plane AC as shown in the figure below.

X A Y

B

C

Which of the following statements is/are correct ? (1) X reaches B at the same time as Y reaches C. (2) The velocity of X at B is the same as that of Y at C. (3) Thekinetic energy possessed by X at B is the same as A. (1) only D. (1) and (3) only

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

that of Y at C. C. (2) and (3) only

[3] A bullet of mass 0.01 kg travelling horizontally at 100 m/s is stopped by 0.1 m of concrete. What retarding force is applied to the bullet by the concrete ? A. 0.1 N B. 10 N C. 500 N D. 1000 N E. 50000 N

[4] A system consists of two identical masses travelling in opposite directions with equal speed. Suppose they collide elastically at time tO. Which of the following graphs correctly shows the total momentum of the system before and after the collision ? A

momentum

B

0

time

momentum

0

to

C

to

momentum

D

0

time to

E

time

momentum

0

time to

momentum

0

time to

[5] A trolley of mass 1 kg travelling at 2 m/s on a smooth horizontal plane has a lump of plasticine dropped from height 5 m onto it. If the mass of the plasticine is 2 kg, the velocity of the loaded trolley will be A. 0.67 m/s B. 1.00 m/s C. 1.50 m/s D. 1.33 m/s E. 2.00 m/s [6] A student of mass 50 kg runs up a flight of stairs 15 m high in 20 seconds. The power developed by the student is A. 37.5 W B. 375 W C. 750 W D. 7500 W E. 15000 W

[7] A load of clothes of weight 120N is raised by applied an effort of 90N to the pulley system as shown in the diagrtam below.

90N

120N

When the effort moves through a distance of 1.6 m, the load of clothes is raised by 0.6 m. What is the efficiency of the machine ? A. 30 % B. 50 % C. 60 % D. 80 % E. 100 % [8] The resultant force acting on a particle is zero. Which of the following statements concerning motion of the particle may be true ? A. The particle is accelerating in a straight line. B. The particle is decelerating in a straight line. C. The particle is moving in a circle with constant speed. D. The particle is moving with constant velocity. E. The particle is swinging to and fro. [9] The graph below shows the variation of velocity with time when a metal ball is released from rest and allowed to fall vertically under gravity through oil. velocity/ms-1

10 5

time/s 0

1 2 3 4

Which of the following statements concerning the motion of the ball is/are correct ? (1) The velocity of the ball decreases with time.

(2) The acceleration of the ball decreases with time. (3) The ball stops falling after 4 s. A. (1) only D. (2) and (3) only

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

C. (1) and (3) only

[10] A particle is in motion with a constant force acting on it. Which of the following physical quantities will be changing during the time when the force is acting ? (1) acceleration of the particle (2) momentum of the particle (3) kinetic energy of the particle A. (1) only D. (2) and (3) only

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

[11] Which of the following factors will affect the boiling point (1) the rate of heat supplied (2) the volume of the liquid (3) the atmospheric pressure A. (1) only D. (1) and (2) only

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

C. (1) and (2) only

of a liquid ?

C. (3) only

[12] A fixed mass of gas has its temperature changed from 127°C to 27°C at constant pressure. The ratio of the new volume to the old volume is

A. 27 : 127 B. 127 : 27 C. 3 : 4 D. 4 : 3 E. 1 : 1 [13] Which of the following changes would make hot water in a closed container cool more quickly ?

(1) polishing the container surface (2) roughening the container surface (3) painting the container surface white A. (1) only D. (1) and (3) only

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

C. (3) only

[14] When 40 kg of water falls through a certain distance, its temperature is found to increase by 0.2°C. What is the height through which it has fallen ? (Specific heat capacity of water = 4200 J kg-1K-1. ) A. 4.2 m B. 20 m C. 22 m D. 42 m E. 84 m

[15] It is given that hte specific latent heat of fusion of ice = 33 x 104 J/kg and specific latent heat of vaporization of water = 23 x 105 J/kg. If 1 kg of ice at 0°C and 1 kg of steam at 100°C are mixed in a well insulated vessel, the result will be A. a mixture of ice and ice-cold water B. a mixture of steam and boiling water C. water at 0°C D. water aty 50°C E. water at 280°C [16] In the diagram below, PQR represents the path of a ray of light incident on a semicircular glass slab. Q is tyhe centre of the slab. P Q Z U

R

Y

V

X

Which of the directions U, V, X, Y, Z correctly indicates the subsequent path of the refracted ray ? A. U D. Y

B. V E. Z

C. X

[17] A lens gives sharp image of the lamp filament at P as shown in the figure below. screen lens lamp

P

Which of the following methods could give sharp image of the filament on the screen ? (1) placing another concave lens in front of the lens (2) moving the lamp closer to the lens (3) replacing the lens by another lens of longer focal length A. (1) only D. (2) and (3) only

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

C. (1) and (3) only

[18] Which of the following statements about the properties of light is/are correct ? (1) The speed of light in a vacuum is independent of its wavelength. (2) The wavelength of light will change when it enters a less dense medium. (3) The frequency of light will change when it enters a less dense medium. A. (1) only D. (2) and (3) only

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

C. (1) and (2) only

[19] Which of the following statements concerning the properties of virtual images is/are correct ? (1) Virtual images are visible to naked eye. (2) Virtual images can be formed directly on a screen. (3) Virtual images can be photographed with a camera. A. (1) only D. (2) and (3) only

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

C. (1) and (3) only

[20] An object is placed 20 cm in front of a converging lens of focal length 30 cm. Which of the following statements about its image is/are correct ? (1) The image is real (2) The image is magnified (3) The image is erect A. (1) only D. (2) and (3) only

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

C. (1) and (3) only

[21] A man swimming at the bottom of a pool is looking at an object which is 1 m above water level. If the refractive index of water is 1.33, the apparent distance of the object above water level as seen by the man is A. 0.25 m B. 0.33 m C. 0.75 m D. 1.00 m E. 1.33 m [22] A tube closed at one end can be made to resonate when a vibrating tuning fork of unknown frequency is held near its open end. When the legth of the air column in the tube is increased by 0.4 m resonance again occure. Given that the velocity of sound in air is 340 m/s, what is the frequency of the tuning fork ? A. 135 Hz B. 272 Hz C. 425 Hz D. 544 Hz E. 850 Hz [23] Given that the approximate wavelength of red light is 7 x 10-7m, what is the approximate wavelength of an FM radio wave ? A. 3 x 102 m B. 3 x 10-3 m C. 3 x 10-7 m D. 3 x 10-9 m E. 3 x 10-11 m

[24] An ultrasonic wave is sent from a ship to find the depth of the sea-bed. A signal is received 0.2 second later. Given that the velocity of sound in sea water is 1500 m/s, what is the depth of the sea-bed ? A. 75 m B. 150 m C. 300 m D. 450 m E. 600 m [25] A stationary wave is set up along a string by a vibrator as shown in the diagram below. 20 cm

vibrator

If the frequency of the vibrator is 5 Hz, what is the velocity of the wave set up by the string ? A. 25 cm/s B. 50 cm/s C. 75 cm/s D. 100 cm/s E. 125 cm/s [26] The atomic structure of isotopes of the same element differ from each other by having different numbers of A. electrons B. neutrons C. protons D. electrons and protons E. electrons and neutrons [27] The specifications of the conducting wires P, Q, R, S and T below :

P Q R S T

Metal Resistivity Cross-sectional area -6 (in 10 ohm m) (in cm2) Copper 1.7 0.1 Copper 1.7 0.2 Silver 1.6 0.15 Aluminium 2.7 0.1 Aluminium 2.7 0.2

Which has the smallest resistance per unit length ?

are given in the table

A. P D. S

B. Q E. T

C. R

[28] A transverse wave is travelling steadily from left to right through a series of particles. At a certain instant the wave form is shown as below.

P

Q

*

R

Which of the following statements about the particles is/are correct ? (1) Particle P is moving downwards. (2) Particle Q is moving upwards. (3) Particle R is momentarily at rest. A. (1) only D. (2) and (3) only

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

C. (1) and (2) only

[29] In the circuit below, the resistance of R1, R2 and R3 are all equal to 2 ohms. The power dissipated by R2 is 6V

R2 R1 R3

A. 2 W

B. 4 W

C. 6 W

D. 8 W

E. 10 W

[30] When connected in series in an electric circuit, the power dissipated in each of the two resistors R1 and R2 is in the ratio 1 : 4. What will be the ratio of the power dissipated in R1 and R2 when they are connected in parallel ? A. 1 : 2 B. 2 : 1 C. 1 : 4 D. 4 : 1 E. 1 : 1 [31] The half-life of a radioactive substance is 8 hours. Its initial mass is 3 kg. Find the amount of radioactive substance remaining after 24 hours. A. 0.375 kg B. 0.75 kg C. 1 kg D. 2 kg E. 3 kg [32] When an object is brought near a positively charged gold-leaf electroscope, the divergence of the leaf decreased. The object could be (1) an uncharged insulator (2) a radioactive source (3) an earthed conductor A. (1) only D. (2) and (3) only

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

C. (1) and (2) only

[33] In the circuit shown below, what is the current passing through the ammeter A ?

3A

2A

A. 0 A D. 4 A

1A

A

B. 1 A E. 6 A

C. 2 A

[34] In the circuit below, A1, A2 and A3 are ammeters of negligible internal resistance.

A

A2 S

A

A

A1

A3

What will happen to the readings of the ammeters if the switch S is closed ? Reading of A1 Reading of A2 Reading of A3 A. decreases increases becomes zero B. increases decreases decreases C. increases unchanged unchanged D. unchanged decreases increases E. unchanged increased becomes zero [35] The resistance of a given conducting wire may be increased by (1) decreasing the radius of the wire (2) increasing the length of the wire (3) winding the wire in the form of a coil A. (1) only D. (1) and (3) only

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

C. (1) and (2) only

[36] The figure below shows a bar magnet moving along the diameter of a metal ring. ?

Which of the following will happen ? A. An induced current will flow in a clockwise direction in the ring.

B. An induced current will flow in an anticlockwise direction in the ring. C. The direction of flow of the induced current will depend magnet. D. An alternating current will be produced in the ring. E. No induced current will be produced.

on the strength of the

[37] A milliammeter of resistance 1 ohm has a full-scale deflection of 10 mA. A shunt is connected parallel to it to convert it into an ammeter with full-scale deflection representing 10 A. ?

The resistance of the shunt should be A. 10-3 ohm B. 10-2 ohm C. 10-1 ohm D. 102 ohms E. 103 ohms [38] Eight 100-watt lamps and one 1000-watt heater are all connected in parallel to an electric supply of 200 V. Which of the following fuses should be used ? A. 1 A fuse B. 5 A fuse C. 10 A fuse D. 30 A fuse E. 50 A fuse [39] In the following nuclear reaction, what is the mass number and atomic number of X ? 27 4 13Al + 2 He

A. B. C. D. E.

Mass number 1 0 4 0 1

15P

30 + X

Atomic number 0 -1 2 0 1