set 12 MCQ Questions & Answers Detailed Explanation

Question : 1

Flash light equipped with a new set of batteries, produces bright white light. As the batteries wear out

a) it stops working suddenly while giving white light

b) the light intensity gets reduced with no change in its colour

c) light colour changes first to yellow and then red with no change in intensity

d) colour changes to red and also intensity gets reduced

Question : 2

Sound waves travel fastest in

a) Liquids

b) Gases

c) Solids

d) Vacuum

Question : 3

Given below are two statements, one labelled as Assertion (A) and other labelled as Reason (R).
Assertion (A):
A diamond sparkles more than a glass imitation cut to the same shape.
Reason (R):
The refractive index of diamond is less than that of glass.
In the context of the above two statements, which one of the following is correct?

a) (A) is true, but (R) is false

b) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

c) Both (A) and (R) are true and (R) is the correct explanation of (A)

d) (A) is false, but (R) is true

Question : 4

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 : 5

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 : 6

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