Question

A dipole of moment $\overrightarrow{p}$ is placed normal to an electric field $\overrightarrow{E}$. Work done in rotating it by an angle of $\pi$ is .

• A. pE
• B. +2pE
• C. -2pE
• D. $zero$

Answer 1

The correct option is D $zero$


Work done=${\int }_{90}^{270}-pEsin\theta d\theta ={[-pEcos\theta ]}_{90}^{270}=0$