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Magnetic moment

In physics, the magnetic moment of an object is a vector property, denoted here as m, that determines the torque, denoted here by τ, it experiences in a magnetic flux density B, namely τ = m × B (where × denotes the vector cross product). As such, it also determines the change in potential energy of the object, denoted here by U, when it is introduced to this flux, namely U = −m·B.[1]

Origin

A magnetic moment may have a macroscopic origin in a bar magnet or a current loop, for example, or microscopic origin in the spin of an elementary particle like an electron, or in the angular momentum of an atom.

Macroscopic examples

Microscopic examples

Notes

  1. V. P. Bhatnagar (1997). A Complete Course in ISC Physics. Pitambar Publishing, p. 246. ISBN 8120902025.