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