A metal sphere with radius ra is supported on an insulating stand at the center of a hollow, metal. Spherical shell with radius r b- There is charge +q on the inner sphere and charge -q on the outer spherical shell.
(a) Calculate the potential V(r) for (i) r r b; Take V to be zero when r is infinite.
(b) Show that the potential of the inner sphere with respect to the outer is
(e) Suppose the charge on the outer sphere is not - q but a negative charge of different magnitude, say - Q. Show that the answers for parts (b) and (c) are the same as before but the answer for part (d) is different

Vab E(r) = (1/r.- 1/r.) r?