set 7 MCQ Questions & Answers Detailed Explanation

Question : 1

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

Question : 2

Assertion (A):
In India, electricity distribution companies calculate the consumption of electricity in kWh.
Reason (R):
Electrical system in India works at a frequency of 60 Hz.
Code

a) (A) is true, but (R) is false

b) Both (A) and (R) are true and (R) is the correct explanation of (A)

c) Both (A) and (R) are true, but (R) is not the correct explanation of (A)

d) (A) is false, but (R) is true

Question : 3

Consider the following statements: An ordinary light bulb has a rather short life because the:

1. filament wire is not uniform.
2. bulb cannot be evacuated completely.
3. wires supporting the filament melt at high temperatures.

a) 1 and 2

b) 1 and 3

c) 2 and 3

d) 1, 2 and 3

Question : 4

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 : 5

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

a) Nickel

b) Iron

c) Cobalt

d) Brass

Question : 6

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