set 4 MCQ Questions & Answers Detailed Explanation

Question : 1

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 : 2

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 : 3

Gases are good conductors of electricity at

a) low pressure

b) low temperature

c) high pressure

d) high temperature

Question : 4

The Earth’s magnetic field is due to

a) Moving charges in space outside

b) Currents circulating inside the core

c) Presence of a huge magnet at its centre

d) None of the above

Question : 5

Eddy currents are produced when

a) a metal is kept in steady magnetic field

b) a circular coil is placed in a magnetic field

c) a metal is kept in varying magnetic field

d) through a circular coil, current is passed

Question : 6

One way in which the operation of an n-p-n transistor differs from that of a p-n-p

a) the emitter junction injects minority carriers into base region of the p-n-p

b) the emitter injects holes into the base of the p-n-p and electrons into the base region n-p-n

c) the emitter junction is reverse biased in n-p-n.

d) the emitter injects holes into the base of n-p-n