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

Question : 11

Which of the following sentences is/are correct about a conductor of electricity?

1. Metals in general are good conductors of electricity.
2. Distilled water conducts electricity.
3. Top water conducts electricity.
4. Rubber is a bad conductor of electricity

a) 1, 3 and 4

b) 1 and 2

c) 2 and 3

d) 1, 2 and 3

Question : 12

Which one of the following is a non-magnetic substance?

a) Nickel

b) Iron

c) Cobalt

d) Brass

Question : 13

The magnetic compass is not useful for navigation near the magnetic poles. Since

a) H = 0

b) R = 0

c) V = 0

d) ϴ = 0°

Question : 14 [IAS (Pre) 2011]

What is the difference between a CFL and an LED Lamp?

1. To produce light, a CFL uses mercury vapour and phosphor while an LED lamp uses semiconductor material.
2. The average life span of a CFL is much longer than of an LED lamp.
3. A CFL is less energy efficient as compared to an LED lamp.

a) 1 and 3

b) Only 1

c) 2 and 3

d) 1, 2 and 3

Question : 15 [NDA]

A current I flows through a potential difference V in an electrical circuit containing a resistance R. The product of V and I, i.e., VI may be understood as

a) thermal power radiated by the circuit

b) resistance R

c) heat generated by the circuit

d) rate of change of resistance