set 7 MCQ Questions & Answers Detailed Explanation

Question : 1

If the distance between the conduction band and valence band is 1 eV. This combination is

a) conductor

b) metal

c) semiconductor

d) insulator

Question : 2

Assertion (A) :
Convex mirror is used as a driver mirror.
Reason (R) :
Images formed by convex mirror are diminished in size.

a) A is true but R is false

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

c) Both A and R are individually true but R is NOT the correct explanation of A

d) A is false but R is true

Question : 3

Consider the following statements :

1. Water cannot be made to boil at 90°C.
2. Charge on a conductor is mostly concentrated at places where the surface is mostly plain.
3. The resistance of a fuse wire is high.

a) 3 only

b) 1 and 2

c) 1 only

d) 1, 2 and 3

Question : 4

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 : 5

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.
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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 : 6

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