Question

A magnetic dipole in a constant magnetic field has ;

• A. Minimum potential energy when the torque is maximum.
• B. Zero potential energy when the torque is minimum.
• C. Zero potential energy when the torque is maximum.
• D. Maximum potential energy when the torque is maximum.

Answer 1

Answer: (C)

Zero potential energy when the torque is maximum.

$U=-\overrightarrow{\mu }.\overrightarrow{B}=\mu Bcos\theta$----------1

$\tau =\mu Bsin\theta$--------------2

From 1 and 2, we can say that magnetic field has zero potential energy when the torque is maximum. Hence the answer and option C is correct