User:John R. Brews/Sample: Difference between revisions
imported>John R. Brews |
imported>John R. Brews |
||
| Line 12: | Line 12: | ||
===Macroscopic examples=== | ===Macroscopic examples=== | ||
The [[electric motor]] is based upon the | The [[electric motor]] is based upon the torque experienced by a current loop in a magnetic field. | ||
===Microscopic examples=== | ===Microscopic examples=== | ||
Revision as of 17:59, 18 December 2010
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
The electric motor is based upon the torque experienced by a current loop in a magnetic field.
Microscopic examples
At a fundamental level, magnetic moment is related to the angular momentum of fundamental particles. In this discussion, focus is upon the electron and the atom.
Notes
- ↑ V. P. Bhatnagar (1997). A Complete Course in ISC Physics. Pitambar Publishing, p. 246. ISBN 8120902025.