Question

An electric dipole of moment P is placed along the lines of force of electric field E and is in equilibrium. the work done in deflecting it through an angle of ${180}^0$ is equal to-

• A. $PE$
• B. $+2PE$
• C. $-2PE$
• D. $ZERO$

Answer 1

The correct option is A $PE$

Moment $=P$

electric field $=F$

work done $=pE\cos \theta$

This is the working formula.

now,

$\theta ={180}^0$

$W=pE\cos {180}^0$

$=pE{cos0}^0$

$=pE$