• Subject:


  • Topic:


A bar magnet of magnetic moment 104J/T is free to rotate in a horizontal plane. The work done in rotating the magnet slowly from a direction parallel to a horizontal magnetic field of 4×10–5 T to a direction 60° from the field will be

(a) 0.2 J                          (b) 2.0 J

(c) 4.18 J                        (d) 2 × 102 J