electric potential at a point as the work done in bringing unit positive charge from infinity to the point; electric potential is zero at infinity

electric potential \(V = \dfrac{Q}{4πε_0r} \) at a distance r from a point charge; changes in electric potential

capacitance \(C = 4πε_0R \) for an isolated sphere

Derivation expected from equation for electric potential and \(Q = VC\).

force–distance graph for a point or spherical charge; work done is area under graph

electric potential energy = \(Vq = \dfrac{Qq}{4πε_0r} \) at a distance r from a point charge Q.