Electric Potential of Sphere with Cavity · CAP 2001 #13
Physics · electromagnetism
Problem
A quantity of charge, Q, is distributed uniformly through a sphere of radius R. A smaller sphere, of radius d and concentric with the larger sphere, is now removed from it, leaving a spherical cavity with no charge in it. The charge density of the remaining shell has not changed. The electrostatic potential at a distance r>R, outside the shell, is
(a) 4πϵ01d3Qr3
(b) 4πϵ01rR3Q(R3−d3)
(c) 4πϵ01rd3QR3
(d) 4πϵ01rR3Qd3