​ An electric dipole is placed at a distance of 2 cm from an infinite plane sheet having positive charge density σ0.

Question

An electric dipole is placed at a distance of 2 cm from an infinite plane sheet having positive charge density \(\sigma_{0}.\) Choose the correct option from the following.

(1) Torque on dipole is zero and net force is directed away from the sheet.

(2) Torque on dipole is zero and net force acts towards the sheet.

(3) Potential energy of dipole is minimum and torque is zero.

(4) Potential energy and torque both are maximum.

Answer 1

Correct option is (3) Potential energy of dipole is minimum and torque is zero.

Here \(\mathrm{E}=\frac{\sigma}{2 \epsilon_{0}}, \vec{\tau}=\overrightarrow{\mathrm{P}} \times \overrightarrow{\mathrm{E}}\)

\(\vec{\tau}=0\)

\(\mathrm{U}=-\overrightarrow{\mathrm{P}} \cdot \overrightarrow{\mathrm{E}} \quad \mathrm{U} \rightarrow\) minimum