A magnet of magnetic moment `20` C.G.S. units is freely suspended in a uniform magnetic field of intensity 0.3 C.G.S. units. The amount of work done in deflecting it by an angle of `30^(@)` in C.G.S. unit is

Options

A. `6`
B. `3sqrt(3)`
C. `3(2-sqrt(3))`
D. `3`

Answer

C

Explanation

Work done `W=MB_(H)(1-costheta)`
`=20xx0.3(1-cos30^(@))=6(1-sqrt(3)/2)=3(2-sqrt(3))`