Derive an expression for the electric potential energy of a system of two point charges in the absence of an external electric field.

Derive an expression for electric potential energy of a system of charges in an electric field.

Derive an expression for potential energy of a system of two point charges.

Derive an expression for potential energy of a system of two charges in the absence of the external electrical field.

Derive an expression for potential energy of a system of two charges in the absence of the external electric field.

Derive an expression for the electrostatic potential energy of a system of two point charges and find its relation with electric potential of a charge.

Derive the expression for the potential energy of a system of point charges.

Derive an expression for potential energy of a system of three charges in the absence of external electric field.

Derive the formula for the electric potential energy of system of two charges.