An electric dipole is placed in a uniform electric field. Its potential energy will be minimum when the angle between its dipole moment and the electric field is
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 0°
Potential energy of a dipole in a uniform electric field is given by:
$U = -\vec{p} \cdot \vec{E} = -pE \cos\theta$
where $\theta$ is the angle between the dipole moment $\vec{p}$ and the electric field $\vec{E}$.
Potential energy is minimum when $\cos\theta$ is maximum, i.e., $\cos\theta = 1$
⇒ $\theta = 0^\circ$
∴ The potential energy is minimum when the dipole moment is parallel to the electric field, i.e., $\theta = 0^\circ$