Question

What is magnetic moment of a Bar magnet? How do you measure it?

Answer 1

The magnetic moment of a magnet is a quantity that determines the torque it will experience in an external magnetic field.

Magnetic moment is defined as a vector relating the aligning torque on the object from an externally applied magnetic field to the field vector itself. The relationship is given by:

$\tau =\mu \times B$

where $\tau$ is the torque acting on the dipole and $B$ is the external magnetic field, and $\mu$ is the magnetic moment.

Magnetic moment is measured in units $Nm/T$ or $A{m}^2$