Potential energy of a Bar Magnet in

an uniform magnetic field

 

 

1) As we have previously found the torque acting on the Bar

magnet, in a magnetic field B, is





 

Now amount of work done on the bar magnet for a small angle changed  








2) Therefore total work done for rotating the Bar magnet from an angle












 

 

 









This work is stored as a potential energy ( U ) in the Bar magnet