Bar Magnet Questions

A bar magnet having a magnetic moment of $2\times 10^4{\text{JT}}^{-1}$ is free to rotate in a horizontal plane. A horizontal magnetic field $B=6\times 10^{-4}\text{T}$ exists in the space. The work done in taking the magnet slowly from a direction parallel to the field to a direction $60^{\circ }$ from the field is: