Question

An electric dipole of moment $\overrightarrow{p}$ is placed normal to the lines of force of electric intensity $\overrightarrow{E}$, then work done in deflecting it through an angle of ${180}^o$ is:

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

Answer 1

The correct option is A $pE$

Work done $W=pE(\cos {\varphi }_1-\cos {\varphi }_2)$

${\varphi }_1={90}^{\circ },\varphi ={180}^{\circ }$

$W=pE(0-(-1\left)\right)$

$W=pE$