A solid spherical shell has inner radius ‘a’ and outer radius ‘2a’. atthe center of the shell is located at a point charge +Q. What must the ecess charge of the shell be in order for the charge density on the inner an outer surfaces of the shell to be exactly equal ? Please explain the sol with the help of diagram.

Abhishek Singh
105 Points
6 years ago
Let say  the shell carries q charge on it
due to electrostatic induction the inner radii would have -Q charge on it and the outer one Q+q
to make the charge densities equal
$\frac{Q}{4\pi a^{2}} = \frac{Q+q}{4\pi(2a)^2}$
qhich implies
q = 3Q