The electric filed due to a uniformly charged spherical shell of charge 'Q' and radius 'R' at a distance 'r' is for r<R, and for r>R.
Consider two concentric spherical shells of radius R and 2R; with same surface charge density. If total charge on them is Q, then find electric potential at their centre.
Two concentric spherical conducting shells of radii R and 2R carry charges Q and 2Q respectively. Change in electric potential on the outer shell when both are connected by a conducting wire is