Q. An electric dipole of moment $\overrightarrow{p}$ placed in a uniform electric field $\overrightarrow{E}$ has minimum potential energy when the angle between $\overrightarrow{p}$ and $\overrightarrow{E}$ is
A) Zero
B) $\frac{\pi}{2}$
C) $\pi$
D) $\frac{3\pi}{2}$
Explanation
(a) $U = - PE\cos\theta$
It has minimum value when $\theta = 0{^\circ}$
$i.e.\ {(U)}_{\min} = - PE \times \cos{0{^\circ}} = - PE$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.