question_answer

If a bar magnet of magnetic moment M is freely suspended in a uniform magnetic field of strength B, the work done in rotating the magnet through an angle\[\theta \] is [AFMC 1997; MNR 1998; RPET 1999; MP PMT 1989, 96, 99; MP PET 1984, 89, 2000; UPSEAT 1999, 2000, 05]

A)            \[MB(1-\sin \theta )\]      

B)            \[MB\sin \theta \]

C)            \[MB\cos \theta \]            

D)            \[MB(1-\cos \theta )\]