Question

A circular current loop of magnetic moment M is in an arbitrary orientation in an external magnetic Field . The work done to rotate the loop by 30° about an axis perpendicular to its plane is

• A. MB
• B. $\sqrt { 3 } \frac { \mathrm { MB } } { 2 }$
• C.
• D. Zero.

Answer 1

Answer: (D)

Zero.

Answer 2

Rotation of loop by $30 ^ { \circ }$ about an axis perpendicular to its plane does not change the angle between magnetic moment and magnetic field. Hence no work in done.