set 4 MCQ Questions & Answers Detailed Explanation

Question : 1

Refractive index of an optical medium changes with

1. the nature of the medium.
2. the change in the angle of incidence of the ray.
3. colour of the incident ray.

a) 1 and 2 only

b) 1 and 3 only

c) 2 and 3 only

d) 1, 2 and 3

Question : 2

Transformer is used for

a) To step up DC voltages

b) Converting AC into DC

c) Converting DC into AC

d) To step up or step down AC voltages

Question : 3

The polarity of an unmarked horse shoe magnet can be determined by using

a) an electroscope

b) a charged glass rod

c) a magnetic compass

d) another unmarked bar magnet

Question : 4

What is the essential difference between a terrestrial telescope and an astronomical telescope?

a) A terrestrial telescope forms an erect image while an astronomical telescope forms an inverted image

b) One of the lenses in a terrestrial telescope is concave

c) The final image formed in a terrestrial telescope is virtual

d) A terrestrial telescope forms an inverted image while an a stronomical telescope forms an erect image

Question : 5

Assertion (A) :
A myopic person is advised to use concave lens.
Reason (R) :
The eye lens of a myopic person focuses the parallel rays coming from distant objects in front of the retina.

a) A is true but R is false

b) Both A and R are individually true and R is the correct explanation of A

c) Both A and R are individually true but R is NOT the correct explanation of A

d) A is false but R is true

Question : 6

Which one of the following is correct? Lightning is formed, when

a) strong opposite charges in different clouds break down the resistance offered by intervening air

b) similar charges of electricity rush towards each other and then get repelled

c) clouds strike against impurities in air and hte friction burns up these impurities

d) water vapour produces electricity in the clouds