Hello candidate,

A dipole is in stable equilibrium when the Electric Field and dipole moment are perpendicular to each other or in other words, the angle between electric field and dipole moment is zero degree and torque will be maximum.

In Unstable equilibrium conditions, the angle between dipole moment and electric field is maximum or equal to 180 degrees. The torque produced will be minimum in such Conditions.

Have a Good Day. Hope it helps!!