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 |
0° 90° 180° 30° |
0° |
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., $\theta = 0^\circ$ |