The Collaborative International Dictionary
magnetic moment \magnetic moment\ n. The torque exerted on a magnet or dipole when it is placed in a magnetic field.
Syn: moment of a magnet.
n. (context physics English) The torque exerted on a magnet within a magnetic field; a vector, being the product of the strength of the magnet and the distance between its poles.
n. the torque exerted on a magnet or dipole when it is placed in a magnetic field [syn: moment of a magnet]
The magnetic moment of a magnet is a quantity that determines the torque it will experience in an external magnetic field. A loop of electric current, a bar magnet, an electron (revolving around a nucleus), a molecule, and a planet all have magnetic moments.
The magnetic moment may be considered to be a vector having a magnitude and direction. The direction of the magnetic moment points from the south to north pole of the magnet. The magnetic field produced by the magnet is proportional to its magnetic moment. More precisely, the term magnetic moment normally refers to a system's magnetic dipole moment, which produces the first term in the multipole expansion of a general magnetic field. The dipole component of an object's magnetic field is symmetric about the direction of its magnetic dipole moment, and decreases as the inverse cube of the distance from the object.