A small metallic sphere carrying charge +Q is located at the centre of a spherical cavity in a large uncharged metallic spherical shell. Write the charge on the inner and outer surface of the shell. Write the expression for the electric field at the point?

Explanation

As shown in the adjoining charge -Q is induced on the inner surface of the metallic shell and, in turn, a charge +Q is induced on the outer surface of the shell.
The electric field at point `P_1` situated in the cavity at a distance r from the centre of charged small metallic sphere is
` oversetto E =(1)/(4 pi in _0) .(Q)/(r^(2)) hatr `
The field is solely due to charge +Q of small metallic sphere and there is no field due to charges induced on the hollow metallic shell.