set 9 MCQ Questions & Answers Detailed Explanation

Question : 1

In the circuits shown below the ammeter A reads 4 amp. and the voltmeter V reads 20 volts. The value of the resistance R is

a) slightly less than 5 ohms

b) exactly 5 ohms

c) slightly more than 5 ohms

d) None of these

Question : 2

Due to the earth's magnetic field, charged cosmic ray particles

a) can never reach the equator

b) require greater kinetic energy to reach the equator than the poles

c) require less kinetic energy to reach the equator than the poles

d) can never reach the poles

Question : 3

Electromagnets are made of soft iron because soft iron has

a) low retentivity and low coercive force

b) low retentivity and high coercive force

c) high retentivity and high coercive force

d) high retentivity and low coercive force

Question : 4

Zener breakdown takes place if

a) doped impurity is high

b) less impurity in n-part

c) doped impurity is low

d) less impurity in p-part

Question : 5

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

a) Transistors

b) Calculator

c) Cordless electronic appliances

d) All of the above

Question : 6

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