Magnetism and Matter Problems - Numerical 02

A bar magnet of magnetic moment 1.5 lies aligned with the direction of a uniform magnetic field of 0.22 tesla.

(a) What is the amount of work required to turn the magnet so as to align its magnetic moment.

(i) Normal to the field direction.

(ii) Opposite to the field direction.

What is the torque on the magnet in cases (i) and (ii)?

Sub Topics

Suggested solution:

(a) (i) Work required to turn the magnet normal to the field direction.

= MB = 1.5 x 0.22 J = 0.33 J

(ii) Work required to turn the magnet opposite to the field direction

= 2MB = 2 x 0.33 J = 0.66 J