set 4 MCQ Questions & Answers Detailed Explanation

Question : 1

In an electric motor, conversion takes place of

a) electrical energy into mechanical energy

b) electrical energy into light energy

c) chemical energy into electrical energy

d) electrical energy into chemical energy

Question : 2

The filament of a halogen lamp is an alloy of

a) Tungsten and sodium

b) Tungsten and iodine

c) Tungsten and bromine

d) Molybdenum and sodium

Question : 3

Match list-I with list -II:

a) A – 4 ; B – 3 ; C – 2 ; D – 1

b) A – 3 ; B – 1 ; C – 2 ; D – 4

c) A – 4 ; B – 2 ; C – 3 ; D – 1

d) A – 2 ; B – 3 ; C – 1 ; D – 4

Question : 4

An alternating current can be converted into direct current by a

a) transformer

b) dynamo

c) rectifier

d) motor

Question : 5

An oscillator is nothing but an amplifer with

a) negative feedback

b) large gain

c) positive feedback

d) no feedback

Question : 6

Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band gap respectively equal to (E_g )_C , (E_g )_Si and (E_g )_Ge. Which of the following statements is true?

a) (E_g )_C < (E_g )_Ge < (E_g )_Si

b) (E_g )_C > (E_g )_Si > (E_g )_Ge

c) (E_g )_Si < (E_g )_Ge < (E_g )_C

d) (E_g )_C = (E_g )_Si = (E_g )_Ge