Question

An electric dipole of length 2 cm, when placed with its axis making an angle of 60${}^o$ with a uniform electric field, experiences a torque of $6\sqrt{3}$Nm. Calculate the potential energy of the dipole, if it has a charge of $\pm$2 nC.

Answer 1

Torque on the dipole, $\tau =MBsin\theta$

Potential energy of the dipole, $U=-MBcos\left(\theta \right)$

$\therefore U=-\tau cot\theta$

$U=-6\sqrt{3}\cot 60=-6J$