set 7 MCQ Questions & Answers Detailed Explanation

Question : 1

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 : 2

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 : 3

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 : 4

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 : 5

When the S–pole of a magnet is placed near an unknown pole of another magnet, the two magnets

a) attract each other because the unknown pole is S–pole

b) repel each other because the unknown pole is N–pole

c) repel each other because the unknown pole is S–pole

d) can either attract or repel

Question : 6

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