electric current and magnetism - Category wise Question and Answer Practice Test with Solutions

Question : 26

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

a) base

b) collector

c) emmiter

d) can be any of the above three

Question : 27

The heating element of an electric heater should be made with a material, which should have

a) high specific resistance and low melting point

b) low specific resistance and low melting point

c) high specific resistance and high melting point

d) low specific resistance and high melting point

Question : 28

Consider the following statements :

1. An ammeter should have low resistance
2. An ammeter should have high resistance
3. A voltmeter should have low resistance
4. A voltmeter should have high resistance

a) 2 and 3

b) 1 and 4

c) 1 and 3

d) 2 and 4

Question : 29

p-n junction diode works as a insulator, if connected

a) in forward bias

b) in reverse bias

c) to A.C.

d) None of these

Question : 30 [NDA]

An object is kept 5 cm in front of a concave mirror of focal length 15 cm. What will be the nature of the image?

a) Real, not magnified

b) Virtual, not magnified

c) Virtual, magnified

d) Real, magnified