electromagnetism (redirected from Electricity and magnetism)

electromagnetism

Branch of physics that deals with the relationship between electricity and magnetism. Their merger into one concept is tied to three historical events. Hans C. Orsted's accidental discovery in 1820 that magnetic fields are produced by electric currents spurred efforts to prove that magnetic fields can induce currents. Michael Faraday showed in 1831 that a changing magnetic field can induce a current in a circuit, and James Clerk Maxwell predicted that a changing electric field has an associated magnetic field. The technological revolution attributed to the development of electric power and modern communications can be traced to these three landmarks.

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electromagnetism

1. magnetism produced by an electric current

2. the branch of physics concerned with magnetism produced by electric currents and with the interaction of electric and magnetic fields

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electromagnetism [i¦lek·trō′mag·nə‚tiz·əm]

(physics)

Branch of physics relating electricity to magnetism.

Magnetism produced by an electric current rather than by a permanent magnet.

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Electromagnetism

The branch of science dealing with the observations and laws relating electricity to magnetism. Electromagnetism is based upon the fundamental observations that a moving electric charge produces a magnetic field and that a charge moving in a magnetic field will experience a force. The magnetic field produced by a current is related to the current, the shape of the conductor, and the magnetic properties of the medium around it by Ampère's law. The magnetic field at any point is described in terms of the force that it exerts upon a moving charge at that point. The electrical and magnetic units are defined in terms of the ampere, which in turn is defined from the force of one current upon another. The association of electricity and magnetism is also shown by electromagnetic induction, in which a changing magnetic field sets up an electric field within a conductor and causes the charges to move in the conductor. See Eddy current, Electricity, Electromagnetic induction, Faraday's law of induction, Hall effect, Inductance, Lenz's law, Reluctance