Magnetic Field

A magnetic field may be represented by a mathematical description of the magnetic influence of electric currents and magnetic materials. The magnetic field at any given point is specified by both a direction and a magnitude (or strength); as such it is a vector field. The magnetic field is most commonly defined in terms of the Lorentz force it exerts on moving electric charges. There are two separate but closely related fields to which the name "magnetic field" can refer, denoted by the symbols B and H.

Magnetic fields are produced by moving electric charges and the intrinsic magnetic moments of elementary particles associated with a fundamental quantum property, their spin. In special relativity, electric and magnetic fields are two interrelated aspects of a single object, called the electromagnetic tensor; the split of this tensor into electric and magnetic fields depends on the relative velocity of the observer and charge. In quantum physics, the electromagnetic field is quantized and electromagnetic interactions result from the exchange of photons.

Magnetic fields have had many uses in ancient and modern society. The Earth produces its own magnetic field, which is important in navigation. Rotating magnetic fields are utilized in both electric motors and generators. Magnetic forces give information about the charge carriers in a material through the Hall effect. The interaction of magnetic fields in electric devices such as transformers is studied in the discipline of magnetic circuits.

Read more about Magnetic Field:  History, Definitions, Units, and Measurement, Magnetic Field Lines, Magnetic Field and Permanent Magnets, Magnetic Field and Electric Currents, Relation Between H and B, Energy Stored in Magnetic Fields

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Spacecraft Magnetometer - Configurations of Magnetometers - Dual Technique
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Coil Knot
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... Magnetic current imaging uses the magnetic fields produced by currents in electronic devices to obtain images of those currents ... though the fundamental physics relationship between magnetic fields and current, the Biot-Savart Law B is the magnetic induction, Idℓ is an element of the current, the constant µ0 is the permeability of free space ... As a result, the current can be directly calculated from the magnetic field knowing only the separation between the current and the magnetic field sensor ...

Famous quotes containing the words field and/or magnetic:

    Something told the wild geese
    It was time to go.
    Though the fields lay golden
    Something whispered—”Snow.”
    —Rachel Lyman Field (1894–1942)

    We are in great haste to construct a magnetic telegraph from Maine to Texas; but Maine and Texas, it may be, have nothing important to communicate.
    Henry David Thoreau (1817–1862)