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 N C−1. Calculate the magnitude of the torque acting on the dipole

Question 1.10: 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 N C⁻¹. Calculate the magnitude of the torque acting on the dipole.

Answer:

Solution -1 

Electric dipole moment, p = 4 × 10⁻⁹ C m

Angle made by p with a uniform electric field, θ = 30°

Electric field, E = 5 × 10⁴ N C⁻¹

Torque acting on the dipole is given by the relation, τ = pE sinθ

 
Therefore, the magnitude of the torque acting on the dipole is 10⁻⁴ N m.

Solution -2