Question

An electric dipole of moment p is placed in a position of stable equilibrium in a uniform electric field of intensity E.

What amount of work will be done if the dipole is rotated through an angle θ from its initial position?

Answer 1

Dear Student,

Work Done by an electric dipole

$$\begin{gathered} U=-\overrightarrow{p}.\overrightarrow{E} \\ stableequilibriumisthestatewherethedipolemomentisparalleltotheelectricfield \\ i.e\theta =0 \\ orP.Einitially=-pE\cos 0orU=-pE(min) \\ Whenitsrotatedbyangle\theta \\ U=-pE\cos \theta \\ Thusworkdone=ChangeinP.E \\ or,W=-pE\left(\cos \theta -1\right) \end{gathered}$$

Regards.