set 12 MCQ Questions & Answers Detailed Explanation

Question : 1

When a person enters into a dark room from the strong light area, he is not able to see clearly for some time. Later he gradually begins to see things. This is because

a) Bleaching and reformation of Rhodopsins

b) Changes in the diameter and focal length of lens

c) Changes in the size of pupil

d) Eyes become familiar with darkness in course of time

Question : 2

The ability of an optical instrument to show the images of two adjacent point objects as separate is called

a) resolving power

b) dispersive power

c) magnifying power

d) None of these

Question : 3

A spherical air bubble is embedded in a piece of glass. For a ray of light passing through the bubble, it behaves like a

a) plano-converging lens

b) converging lens

c) diverging lens

d) plano-diverging lens

Question : 4

Which of the following statement is true?

a) Celestial objects have the greatest velocity

b) The sound has the greatest velocity

c) The light has a greater velocity

d) Rocket has the greatest velocity

Question : 5

The rate of flow of heat through a rod depends on:

a) temperature difference across the rod.

b) thermal conductivity of the rod.

c) length of the rod.

d) All of these

Question : 6

If the lens power of glass is +2 dioptre, its focal length will be

a) 50 cm

b) 100 cm

c) 200 cm

d) 2 cm