set 14 MCQ Questions & Answers Detailed Explanation

Question : 1

Consider the following phenomena.

1. Size of the Sun at dusk
2. Colour of the Sun at dawn
3. Moon being visible at dawn
4. Twinkle of stars in the sky
5. Polestar being visible in the sky

a) 1, 2 and 4

b) 3, 4 and 5

c) 1, 2 and 3

d) 2, 3 and 5

Question : 2

Consider the following statements:

1. Steam at 100°C and boiling water at 100°C contain same amount of heat.
2. Latent heat of fusion of ice is equal to the latent heat of vaporization of water.
3. In an air-conditioner, heat is extracted from the room air at the evaporator coils and is rejected out at the condenser coils.

a) 2 and 3

b) 1 and 2

c) Only 2

d) Only 3

Question : 3

The frequency of a wave travelling at a speed of 500 ms^–1 is 25Hz. Its time period is

a) 25 s

b) 20 s

c) 0.05 s

d) 0.04 s

Question : 4

Consider telecommunication through optical fibres. Which of the following statements is not true ?

a) Optical fibres may have homogeneous core with a suitable cladding

b) Optical fibres are subject to electromagnetic interference from outside

c) Optical fibres have extremely low transmission loss

d) Optical fibres can be of graded refractive index

Question : 5

Total internal reflection can take place only if

a) the refractive indices of the two media are close to different

b) light goes from optically rarer medium to optically denser medium

c) light goes from optically denser medium to rarer medium

d) the refractive indices of the two media are widely different

Question : 6

An air bubble inside water behaves as a

a) Divergent lens

b) Convergent lens

c) Bifocal lens

d) Cylindrical lens