question_answer

An electric dipole is a pair of equal and opposite charges, separated by a small fixed distance between them. The dipole is free to move. What is the action on it, when it is placed in (i) a uniform electric field, and (ii) a non-uniform electric field?

Answer:

                (i) In a uniform electric field, an electric dipole experiences two equal, opposite and parallel forces at its two ends. The net force on it is zero but it experiences a torque due to which it rotates about an axis perpendicular to the electric field and passing through its mid-point. (ii) In a non-uniform electric field, an electric dipole experiences two unequal and non-parallel forces at its two ends. The two forces add up to give a resultant force and a torque. So the dipole will accelerate linearly in the direction of the resultant iorce and also accelerate angularity in the direction of 'be resultant torque.