Q.An electric dipole of moment $5\times10^{-8}\ \text{C·m}$ is placed in a uniform electric field of magnitude $2\times10^{4}\ \text{N/C}$ such that the dipole moment makes an angle of $30^\circ$ with the field. Find the torque on the dipole.

Torque on a dipole τ = pE sinθ is maximum when sinθ = 1, i.e. θ = 90°.

Torque on an electric dipole in a uniform field: $\tau = pE\sin\theta$, where $\theta$ is the angle between the dipole moment $\vec p$ and the field $\vec E$. This is maxi …

The torque on an electric dipole in a uniform field is the vector (cross) product of its dipole moment and the field.

A dipole of moment p, placed in a uniform electric field E, experiences equal and opposite forces on its two charges, forming a couple. The torque of this couple i …