set 8 MCQ Questions & Answers Detailed Explanation

Question : 1

Fluorescent tubes are fitted with a choke. The choke coil :

a) reduces current in the circuit

b) steps up the line voltage

c) steps-down the line voltage

d) chokes low frequency current

Question : 2

In semiconductors, at room temperature

a) the valence band is partially empty and the conduction band is partially filled

b) the valence band is completely filled and the conduction band is partially filled

c) the conduction band is completely empty

d) the valence band is completely filled

Question : 3

Nickel-Cadmium (Ni-Cd) battery is used in

a) Transistors

b) Calculator

c) Cordless electronic appliances

d) All of the above

Question : 4

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 : 5

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

a) Transformer

b) Inverter

c) Rectifier

d) Transmitter

Question : 6

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