Question

An electric dipole kept in a uniform electric field experiences:
A) Force and torque
B) A force, but no torque
C) A torque but no force
D) Neither a force nor a torque

Answer 1

Hint
We know that moving current produces magnetic fields according to Biot-Savart's law:
$B = \dfrac{{{\mu _0}}}{{4\pi }}.\dfrac{{idl.\sin \theta }}{{{r^2}}}$
In electrical signalling an analog current loop is used where a device must be monitored or controlled remotely over a pair of conductors.

Complete Solution step by step
Current loop as a magnetic dipole behaves like a magnet. It has magnetic field lines as well as north and south poles just like a bar magnet.To put all this in a simpler perspective, imagine a clock. Now the clock completes one round from 12 - 12. That direction is what we call clockwise. So if current is clockwise direction then the direction of magnetic field lines will be in inward direction.
Similarly, direction opposite to movement of clock is called anti-clockwise direction. So if current is moving in anti-clockwise direction then direction of magnetic field lines will be in outward direction.i.e If current is in anti-clockwise direction then direction of magnetic field lines will be in outward direction. If current is in clockwise direction the direction of magnetic field lines will be in inward direction. Now, In a uniform electric field, both the point charges comprising the dipole will experience force, equal in magnitude and opposite in direction.
Though the net force will always be zero, the torque will be in the same direction for both the charges. Hence torque will not be zero.
Option (C) is the correct answer.

Note
Current loop behaves like bar magnet because magnetic field created by bar magnet and current loop shows same amount of deflection in magnetic needle when brought near.