A metallic spherical shell has an inner radius R_1 and outer radius R_2. A charge Q is placed at the center of the spherical cavity. What will be the surface charge density on the outer surface ?

A metallic spherical shell has an inner radius R_1 and outer radius R_2 . A charge Q is placed at the center of the spherical cavity. What will be the surface charge density on the inner surface ?

A thin metallic spherical shell contains a charge Q on its surface. A point charge q_1 , is placed at the center of the shell, and another charge q_2 is placed outside the shell. All the three charges are positive. Then the force on charge q, is

Two combining spheres A and B of radius a and b respectively are at the same potential. The ratio of the surface charge densities of A and B is ________.

A hollowing metallic sphere of radius 10cm is charged such that potential on its surface is 80V. the potential at the center of the sphere would be.