A circular current loop of magnetic moment `M` is in an arbitrary orientation in an external magnetic field `vec(B)`. The work done to rotate the loop by `30^(@)` about an axis perpendicular to its plane is `:`

Options

A. `MB`
B. `sqrt(3)(MB)/(2)`
C. `(MB)/(2)`
D. zero

Answer

4

Explanation

No work is down to rotate the loop about an axis perpendicular to its plane as `vec(M)` is directed along the axis. Work is down only when the plane of the loop rotates.