Question

The diagram of Van de Graff generator is shown. Leakage of charge is minimized by enclosing the set-up in a:

(A). plastic chamber
(B). steel chamber
(C). evacuated chamber
(D). double-walled glass container

Answer 1

Hint: A Van de Graaff generator is used to accumulate a very large amount of charge which can then be used for various purposes like generating DC current. Since air is also a conductor of charge, some of the charge from the generator can escape into air, in order to prevent it the apparatus is closed.

Complete answer:
The Van de Graaff generator is used to generate electrostatic energy. A belt is used to collect electric charge on a hollow sphere which is supported on an insulated column creating very high potential. The Van de Graaff generator is used to create very high voltage direct current.
The Van de Graaff generator consists of a rubber belt wound over two rollers of different material. One of the rollers is surrounded by the hollow sphere. Two com-like electrodes are present near the lower roller and inside the hollow sphere.
It works on the principle of triboelectric effect, according to it, simple contact between dissimilar surfaces causes transfer of electrons from one surface to the other.
The whole apparatus is enclosed in a steel tank as well as air pressure is increased to decrease leakage of charge and hence conductivity of air.
Therefore, the set up is enclosed in a steel tank to decrease charge leakage.

Hence, the correct option is (B).

Note:
There is no charge inside a hollow conductor; the whole charge is concentrated on the surface. Air is also a conductor of charge and the charge accumulated in the Van de graaff generator can flow through air, this is called leakage of charge. When two surfaces are rubbed together transfer of charges takes place.