Figure shows three concentric thin spherical shells A, B and C of radii a, b and c respectively. The shells A and C are given charges q and -q respectively and the shell B is earthed. Find the charges appearing on the surfaces of B and C.

Answer

A, B, C

Explanation

Let `Q` is the charge on shell B (which comes from earth)
`V_B=0`
`:. (kq)/b+(kQ)/b-(kq)/c=0`
`:. Q=(b/c-1)q`
Charges appearing on different faces are as shown below