Exercise 2

Question 1 :

On a rainy day, small oil films on water show brilliant colours. This is due to

A). dispersion
B). interference
C). diffraction
D). polarization
Answer : Option B

Question 2 :

Point A is at a lower electrical potential than point B. An electron between them on the line joining them will

A). move towards A
B). move towards B
C). move at right angles to the line joining A and B
D). remain at rest
Answer : Option B

Question 3 :

Materials for rain-proof coats and tents owe their water-proof properties to

A). surface tension
B). viscosity
C). specific gravity
D). elasticity
Answer : Option A

Question 4 :

RADAR is used for

A). locating submerged submarines
B). receiving a signals in a radio receiver
C). locating geostationary satellites
D). detecting and locating the position of objects such as aeroplanes
Answer : Option D

Question 5 :

Sound of frequency below 20 Hz is called

A). audio sounds
B). infrasonic
C). ultrasonic
D). supersonics
Answer : Option B

Question 6 :

On a clean glass plate a drop of water spreads to form a thin layer whereas a drop of mercury remains almost spherical because

A). mercury is a metal
B). density of mercury is greater than that of water
C). cohesion of mercury is greater than its adhesion with glass
D). cohesion of water is greater than its adhesion with glass
Answer : Option C

Question 7 :

Suitable impurities are added to a semiconductor depending on its use. This is done in order to

A). increase its life
B). enable it to withstand higher voltages
C). increase its electrical conductivity
D). increase its electrical resistivity
Answer : Option C

Question 8 :

Stars twinkle because

A). the intensity of light emitted by them changes with time
B). the distance of the stars from the earth changes with time
C). the refractive index of the different layers of the earth's atmosphere changes continuously, consequently the position of the image of a start changes with time
D). the light from the star is scattered by the dust particles and air molecules in the earth's atmosphere
Answer : Option C

Question 9 :

It takes much longer to cook food in the hills than in the plains, because

A). in the hills the atmospheric pressure is lower than that in the plains and therefore water boils at a temperature lower than 100oC causing an increase in cooking time
B). due to low atmospheric pressure on the hills, the water boils at a temperature higher than 100oC and therefore water takes longer to boil
C). in the hills the atmospheric density is low and therefore a lot of heat is lost to the atmosphere
D). in the hills the humidity is high and therefore a lot of heat is absorbed by the atmosphere leaving very little heat for cooking
Answer : Option A

Question 10 :

Moment of inertia is

A). vector
B). scalar
C). phasor
D). tensor
Answer : Option D

Question 11 :

Of the following natural phenomena, tell which one known in Sanskrit as 'deer's thirst'?

A). Rainbow
B). Earthshine
C). Halo
D). Mirage
Answer : Option D

Question 12 :

Inside an aeroplane, flying at a high altitude,

A). the pressure is the same as that outside
B). normal atmospheric pressure is maintained by the use of air pumps
C). the pressure inside is less than the pressure outside
D). normal humidity and partial vacuum are maintained
Answer : Option B

Question 13 :

Sound travels with a different speed in media. In what order does the velocity of sound increase in these media?

A). Water, iron and air
B). Iron, air and water
C). Air, water and iron
D). Iron, water and air
Answer : Option C

Question 14 :

One thousand microns is equal to

A). 10-3m
B). 10-6m
C). 10-9m
D). 10-12m
Answer : Option A

Question 15 :

Sound travels at the fastest speed in

A). steel
B). water
C). air
D). vacuum
Answer : Option A

Question 16 :

oil raise up the wick in a lamp. The principle involves

A). the diffusion of oil through the wick
B). the liquid state of oil
C). capillary action phenomenon
D). volatility of oil
Answer : Option C

Question 17 :

Superconductors are substances which

A). conduct electricity at low temperature
B). offer high resistance to the flow of current
C). offer no resistance to the flow of electricity
D). conduct electricity at high temperatures
Answer : Option C

Question 18 :

Light travels at the fastest speed in

A). glass
B). water
C). hydrogen
D). vacuum
Answer : Option D

Question 19 :

Railway tracks are banked on curves

A). necessary centrifugal force may be obtained from the horizontal component weight of the train
B). to avoid frictional force between the tracks and wheels
C). necessary centripetal force may be obtained from the horizontal component of the weight of the train
D). the train may not fly off in the opposite direction
Answer : Option C

Question 20 :

On a cold day when a room temperature is 15oC, the metallic cap of a pen becomes much colder than its plastic body, though both are at the same temperature of 15oC, because

A). metals have higher thermal capacity than plastics
B). plastics have a lower density than metals
C). metals are good conductor of heat
D). plastics have a higher thermal conductivity than metals
Answer : Option C

Question 21 :

Sound produced at a point is heard by a person after 5 second, while the same sound is heard by another person after 6 seconds. If the speed of sound is 300 m/s, what could be the maximum and minimum distances between the two persons?

A). 1.8 km, 0.15 km
B). 2.2 km, 0.20 km
C). 2.8 km, 0.25 km
D). 3.3 km, 0.30 km
Answer : Option D

Question 22 :

Intensity of sound at a point is ____ its distance from the source.

A). directly proportional to
B). inversely proportional to
C). directly proportional to square of
D). inversely proportional to square of
Answer : Option D

Question 23 :

Of the four locations mentioned below the highest inside temperature will be attained in the pressure cooker operated with the pressure valve open

A). at sea level
B). at the top of Mt. Everest
C). at a place in a valley below sea level
D). in an aeroplane flying at a height of 10,000 m with inside pressure maintained at the sea level
Answer : Option C

Question 24 :

Radio telescopes are better than optical telescopes because

A). they can detect faint galaxies which no optical telescope can
B). they can work even in cloudy conditions
C). they can work during the day and night
D). All of the above
Answer : Option D

Question 25 :

Light Emitting Diodes (LED) is used in fancy electronic devices such as toys emit

A). X-rays
B). ultraviolet light
C). visible light
D). radio waves
Answer : Option C