Question

State the conditions under which the dipole is in (i) stable equilibrium and (ii) unstable equilibrium

Answer 1

A dipole in a uniform electric field is in stable or unstable equilibrium according as the angle between the dipole and electric field is 0 or 180. Further, in case of unstable equilibrium there will occur dipole moment.

Unstable equilibrium when the electric filed is directed at an angle of 180 degrees with the direction of the dipole, i.e., when is anti-parallel to. A dipole placed in a uniform electric filed is in Stable equilibrium when the electric field is directed along the direction of the dipole i.e., when is parallel to.