Magnetic moment

Introduction and definition
- Formula
Potential energy
Sources

Introduction and definition

The magnetic moment $\mu$ defines the torque that an object experiences in a magnetic field.

$\tau = \mu \times \textbf{B}$

The torque (torque exerted by the magnetic force) is equal to the cross product of the magnetic moment and the magnetic field.

Formula

A solenoid is a coil of wire that produces a magnetic field when an electric current is passed through it. The magnetic moment is defined as the current times the area times N (number of loops):

$\mu = NIA$

Potential energy

The potential energy is defined as the dot product of the magnetic moment and the magnetic field:

$U = - \mu B$

Sources

Magnetic Dipole Moment
Solenoid - Wikipedia