Question

What is the relationship between the torque direction and the direction of dipole rotation?

Options

• The torque rotates the dipole away from the field direction

• The torque direction is perpendicular to both the dipole and field

• The torque rotates the dipole toward alignment with the field direction

• The torque prevents any rotation of the dipole

Answer 1

The torque \[\tau = \mathbf{p} \times \mathbf{E}\] acts to rotate the dipole such that the dipole moment vector aligns with the electric field vector. This rotation continues until θ = 0°, at which point the torque becomes zero. The direction of the cross product ensures the dipole is rotated toward the field direction.