A solid conducting sphere of radius `a` has a net positive charge `2Q`. A conducting spherical shell of inner radius `b` and outer radius `c` is concentric with the solid sphere and has a net charge `-Q`. The surface charge density on the inner and outer surfaces of the spherical shell will be

Options

A. `-(2Q)/(4pib^2),(Q)/(4pic^2)`
B. `-(Q)/(4pib^2),(Q)/(4pic^2)`
C. `0,(Q)/(4pic^2)`
D. None of the above

Answer

A

Explanation

`sigma_("inner") = (-2Q)/(4pib^2)`
`sigma_("outer") = (Q)/(4pic^2)`