set 8 MCQ Questions & Answers Detailed Explanation

Question : 1

When an optician prescribes a – 5D lens, what does it mean?

a) Concave lens of 5 cm focal length

b) Concave lens of 20 cm focal length

c) Convex lens of 5 cm focal length

d) Convex lens of 5 cm focal length

Question : 2

The device used for converting alternating current to direct current is called

a) Transformer

b) Inverter

c) Rectifier

d) Transmitter

Question : 3

The part of the transistor which is heavily doped to produce large number of majority carriers is

a) base

b) collector

c) emitter

d) any of the above depending upon the nature of transistor

Question : 4

The ratio of the focal length of the objective to the focal length of the eyepiece is greater than one for

a) both microscope and telescope

b) a microscope

c) a telescope

d) neither microscope nor telescope

Question : 5

In charging a battery of motor car, the following effect of electric current is used

a) heating

b) chemical

c) magnetic

d) induction

Question : 6

A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of

a) each of them decreases

b) copper increases and germanium decreases

c) each of them increases

d) copper decreases and germanium increases