Physics C: E&M · FRQ Trainer

A solid insulating sphere of radius R has a uniform volume charge density ρ. (a) Use Gauss's Law to derive an expression for the magnitude of the electric field E(r) inside the sphere (r < R). (b) Derive an expression for the electric potential V(r) at the surface of the sphere, assuming V = 0 at infinity. (c) A proton (charge +e) is released from rest at the surface. Determine its kinetic energy when it reaches a distance 3R from the center.