Two electric dipoles, each of dipole moment ' $P$ ' are placed at points $A(a, 0)$ and $B(-a, 0)$ as shown…
Two electric dipoles, each of dipole moment ' $P$ ' are placed at points $A(a, 0)$ and $B(-a, 0)$ as shown in the figure. The work done in rotating both the dipoles through $90^{\circ}$ in clockwise direction is
$(E=\text { Electric field })$
PE
Zero
$2 \mathrm{PE}$
$\frac{P E}{2}$
Solution
Work done due to dipole, $\mathrm{W}=-\mathrm{p} E \cos \theta$ Here $\mathrm{W}=\mathrm{W}_{90}-\mathrm{W}_0$ $=(-\mathrm{PE} \cos 90)-(-\mathrm{pE} \cos 0)=\mathrm{PE}$
