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 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 ?

Two charged conducting spheres of radii a and b are connected to each other by a wire. What is the ratio of electric fields at the surfaces of the two spheres? Use the result obtained to explain why charge density on the sharp and pointed ends of a conductor is higher than on its flatten portions.

Two spheres of Copper of same radii, one hollow and the other solid are charged to the. same potential. Which sphere has more charge?

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 ?