Action of an electric field on a dipole
Potential energy
The potential energy (U) of an electric dipole in an external electric field is defined as the work done by the electric field to orient the dipole relative to its natural direction

Moment of torque
The moment of torque (τ) of an electric dipole in an external electric field measures the tendency of the dipole to align with the field.
When the dipole undergoes an electric field, it undergoes , the torque acts to orient the dipole so as to reduce the angle θ
