This lecture covers the concept of electrostatic potential energy, where a charge is moved quasi-statically under the action of electric forces, resulting in work done by the force. The electric potential at a point in an electric field is defined as the energy, analogous to gravitational potential energy. The lecture also discusses the independence of work performed on the path taken, the electric potential energy of a charge in an electric field, and the total electrostatic potential energy of a charge distribution. Examples of point charges in electric fields are provided, along with the concept of energy density and the divergence theorem.