Q 12-02-061JEE MainJEE Main 2025 (29 Jan, Shift 2)Medium
An electric dipole is placed at a distance of $2\ \text{cm}$ from an infinite plane sheet having positive charge density $\sigma_0$, as shown in the figure. Choose the correct option from the following.
Answer: (D) Potential energy of dipole is minimum and torque is zero.
The sheet produces a uniform field $\dfrac{\sigma_0}{2\epsilon_0}$ pointing away from it.
The dipole moment points from $-q$ to $+q$, i.e. away from the sheet: parallel to the field.
- Torque $pE\sin0^\circ = 0$.
- Potential energy $U = -pE\cos0^\circ = -pE$, its minimum value.
- In a uniform field the forces on $+q$ and $-q$ cancel, so there is no net force (ruling out options 2 and 3).
Solution by Sreeraj P, M.Sc Physics