Question

When the dipole moment is parallel to the electric field (θ = 0°), what is the magnitude of torque?

Options

• pE

• pE/2

• 2pE

• Zero

Answer 1

When θ = 0°, we have τ = pE sin(0°) = pE × 0 = 0. This is because when the dipole is aligned with the field, the perpendicular distances from the center to the lines of action of both forces become zero, resulting in no torque.