set 7 MCQ Questions & Answers Detailed Explanation

Question : 1

The earth’s magnetic field is approximately

a) 10 Tesla⁴

b) 1 Tesla

c) 2 Gauss

d) 1 Gauss

Question : 2

A device which converts chemical energy into electrical energy is called

a) Generator

b) Battery

c) Motor

d) Moving coil meter

Question : 3

In an unbiased p-n junction, holes diffuse from the p-region to n-region because

a) they move across the junction by the potential difference.

b) hole concentration in p-region is more as compared to n-region.

c) free electrons in the n-region attract them.

d) all the above

Question : 4

The core of a transformer is laminated because

a) rusting of the core may be prevented

b) ratio of voltage in primary and secondary may be increased

c) the weight of the transformer may be reduced

d) energy losses due to eddy currents may be minimised

Question : 5

Consider the following statements :

1. Diamagnetism is temperature independent.
2. Paramagnetism is explained by domain theory.
3. Above curie temperature a ferromagnetic material becomes paramagnetic.
4. Magnetic susceptibility is small and negative for diamagnetic substance.

a) 1, 2 and 3

b) 1 only

c) 2 only

d) 2 and 4

Question : 6

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