# The radii of three thin concentric metal shells A, B, and C are a, b, and c respectively. The shells A and C are given charges q and −q respectively while the middle shell B is earthed as shown in the figure.The charges appearing on the inner and the outer surfaces of sphere B are

$\begin{array}{1 1}(A)\;-q\;and\;bq/c \\ (B)\;-q\;and\;+q \\ (C)\;bq/c \;and\;+q \\(D)\;+q\;and\;-q \end{array}$

The charges appearing on the inner and the outer surfaces of sphere B are $-q\;and\;+q$
Hence B is the correct answer.
answered May 29, 2014 by