Magnetism

In physics, magnetism is one of the phenomena by which materials exert an attractive or repulsive force on other materials. Some well known materials that exhibit easily detectable magnetic properties are iron, some steels, and the mineral lodestone; however, all materials are influenced to one degree or another by the presence of a magnetic field, although in most cases the influence is too small to detect without special equipment.

Charged particle in a magnetic field

When a charged particle moves through a magnetic field B, it feels a force F given by the cross product:

Related Topics:
Magnetic field - Force - Cross product

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:ec F = q ec v imes ec B

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where

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:q, is the electric charge of the particle

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:ec v , is the velocity vector of the particle

Related Topics:
Velocity - Vector

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:ec B , is the magnetic field

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Because this is a cross product, the force is perpendicular to both the motion of the particle and the magnetic field. It follows that the magnetic force does no work on the particle; it may change the direction of the particle's movement, but it cannot cause it to speed up or slow down.

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