A small conducting spherical shell with inner radius a and outer radius b is concentric with a larger conducting spherical shell with inner radius c and outer radius d. The inner shell has total charge `+2q` and the outer shell has charge `+4q`.
(i) What is the total charge on the (a) inner surface of the small shell, (b) outer surface of the small shell (c) inner surface of the large shell, (d) outer surface of the large shell ?
(ii) Calculate the electric field in terms of q and the the distance r from the common centre of two shells for (a) `r lt a`, (b) `a lt r lt b`, (c) `b lt r lt c`, (d) `c lt r lt d`, (e) `r gt d`