A conducting sphere with radius a = 0.31 m has a net charge Qa = +4.5 µC. A thin, non-conducting spherical shell of radius b = 0.95 m surrounds the sphere and is concentric with it. This shell has a net charge Qb = +1.5 µC distributed uniformly over its surface. The electric potential at infinity is zero
Find the electric potential mid-way between the surface of the sphere and the surrounding shell
