A bar magnet of magnetic moment is placed in the magnetic field . The torque acting on the magnet is:
Step 1: Given Data
Magnetic Moment of the bar magnet
External magnetic field
Let the angle made between the bar magnet and the direction of the external magnetic field be .
Let be the magnitude of the coupling force.
Let is the perpendicular distance between the two couple force.
Let be the current.
Let be the length.
Step 2: Formula Used
We know that force can be given as,
We know that dipole moment is given as,
Step 3: Calculate the Torque
We know that torque is given as,
Hence, the torque acting on the magnet is .