Athin conducting sphere has a charge q and radius a (a i) what is the capacitance of the sphere (relative to a reference plane at infinite distance)? (a ii) what is the energy density of the electric field at a distance r from the center of the sphere, for both ra (a i) what is the total energy of the electric field? express the result in terms of the capacitance obtained in part (a i) and the potential vo on the surface of the sphere. (b) a potential v is established between inner (radius a) and outer (radius b) shells of thin concentric conducting spheres. what is the radius of the inner sphere (i. e. the ratio a/b) such that the electric field on its surface is minimum. express this minimum value in terms of v and b.