An electric dipole is free to move in a uniform electric field. Explain its motion when it is placed.
parallel to the field

perpendicular to the field.

Explanation

When an electric dipole is placed parallel to a uniform electric field. Net force as well as net torque acting on the dipole is zero. Thus, the dipole remains in equilibrium and does not move.
(b) When dipole is placed perpendicular to the field, a torque `oversetto tau =oversetto p xx oversetto E ` acts on it. Under its influence the dipole executes oscillatory motion about the direction of electric field and finally aligns itself along the direction of electric field.