Question

Under what condition is the torque on a dipole in a uniform electric field non-zero?

Options

• When the dipole is perpendicular to the field

• When the dipole is not parallel to the field

• When the dipole is parallel to the field

• In all cases regardless of orientation

Answer 1

The torque on a dipole is given by τ = pE sin θ. When θ = 0° (dipole parallel to field), sin θ = 0 and torque is zero. For any other orientation where the dipole is not parallel to the field, sin θ ≠ 0, producing non-zero torque.