set 8 MCQ Questions & Answers Detailed Explanation

Question : 1

A noise level of 100 decibel would correspond to

a) Ordinary conversation

b) Sound from a noisy street

c) Just audible sound

d) Noise from a machine shop

Question : 2

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 (smaller refractive index) 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 : 3

Consider the following statements:

1. Steam at 100°C and boiling water at 100°C contain the same amount of heat.
2. The 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 only

b) 2 and 3

c) 1 and 2

d) 3 only

Question : 4

Bats can fly during dark nights and also prey. This is because

a) Their night vision is very good

b) Every bird can do this

c) The pupil of their eyes is large

d) They produce ultrasonic waves and are guided by them

Question : 5

A watch shows times as 3 : 25 when seen through a mirror, time appeared will be

a) 7 : 35

b) 8 : 35

c) 9 : 35

d) 8 : 25

Question : 6

A solid is melted (above the melting point) and allowed to cool down at normal condition.Its variation of temperature as a function of times is as shown in the figure given below. What is the reason for the plateau(flat position) in the central region of the cooling curve as shown in the figure?

a) Specific heat of the solid

b) Latent heat of fusion of the solid

c) Thermal conductivity of the solid

d) Thermal capacity of the solid.