A soild spherical conductor of radius R has a spherical cavity of radius `a (a < R)` at its centre. A charge + Q is kept at the centre. The charge at the inner surface, outer and at a position` r (a < r < R) `are respectively

Options

A. `+Q,-Q,0`
B. `-Q,+Q,0`
C. `0,-Q,0`
D. `+Q,0,0.`

Answer

B

Explanation

The charge at the inner surface , outer surface and inside the conductor at `P = (-Q , + Q,0) ` as shown in the figure .
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