Question

The torque acting on an electric dipole of dipole moment P placed at an angle 90 to the electric field

Answer 1

The torque acting on an electric dipole placed in an electric field is given by the equation, τ = pE sinθ.

When the dipole is placed anti parallel to the field, the angle between p and E is 180 degree.

Since sin 180= 0, toque acting on the electric dipole is also zero.