Magnetic field

:For other senses of this term, see magnetic field (disambiguation).

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In physics, a magnetic field is an entity produced by moving electric charges (electric currents) that exerts a force on other moving charges. (The quantum-mechanical spin of a particle produces magnetic fields and is acted on by them as though it were a current; this accounts for the fields produced by "permanent" ferromagnets.) A magnetic field is a vector field: it associates with every point in space a vector that may vary in time. The direction of the field is the equilibrium direction of a compass needle placed in the field.

Related Topics:
Physics - Electric charge - Electric current - Force - Quantum-mechanical - Spin - Ferromagnet - Vector field - Vector - Compass

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