Question 3Explain the principle on which Van de Graff generator
operates. Draw a labeled schematic sketch and write briefly its
working. ORState and prove Gauss theorem in electrostatics.Ans.Van
de Graff, in 1931 designed an electrostatic generator which is
capable of producing very high potential of the order of 10 MV.
Principle: Suppose we have a large spherical conducting shell of
radius R, carrying charge Q. The charge spreads uniformly over
whole surface of the shell. Now suppose a small conducting sphere
of radius r is introduced inside the spherical shell and placed at
its center, so that both the sphere and shell have same center O.
The electric field in the region inside the small sphere and large
shell is due to charge +q only, so electric field strength at a
distance x from the center O is
This is independent of charge Q on the large spherical shell. As
r
