An electric dipole with dipole moment 4 × 10–9 C m is aligned at 30° with the direction of a uniform electric field of magnitude 5 × 104 NC–1. Calculate the magnitude of the torque acting on the dipole.
The electric dipole moment can be defined as the measure of the separation of positive as well as negative charges within a specific system. It tells us about the given system’s overall polarity.
Electric dipole moment, p = 4 × 10–9 C-m
Angle between p and uniform electric field, 
= 30
Electric field, E = 5 × 104 NC–1
The torque acting on a dipole is given by:
τ = p × E
τ = pEsin
= 4 × 10–9 C m x 5 × 104 NC–1 x (0.5)
= 10-4 Nm
The magnitude of torque acting on the given dipole is 10-4 Nm.
11