A charge Q is placed at the centre of an uncharged, hollow metallic sphere of radius a,
(a) Find the surface charge density on the inner surface and on the outer surface.
(b) If a charge q is put on the sphere, what would be the surface charge densities on the inner and the outer surfaces?
(c) Find the electric field inside the sphere at a distance x from the centre in the situations (a) and (b).