Chapter-2|Electrostatic Potential and Capacitance| NCERT 12th Physics:
Potential Energy of a Dipole in an External Field:
Let an electric dipole placed in an uniform electric field E with its dipole moment P making an angle θ with electric field. Two equal and opposite charges exerts forces +qE and -qE acts on its two ends. The two forces form a couple.
The torque exerted by the couple will be
If the dipole is rotated through a small angle dθ against the torque acting on it. Then the the small work done is