Electromagnetism is the branch of physics that studies the electromagnetic force, one of the four fundamental forces of nature, and the electric and magnetic fields through which it acts, unifying what had been treated as separate electric and magnetic phenomena. James Clerk Maxwell's equations, published in the 1860s, gave the field its complete classical mathematical description, showed that light itself is an electromagnetic wave, and predicted the existence of radio waves later confirmed experimentally by Heinrich Hertz. Electromagnetism underlies nearly all modern electrical and electronic technology, including motors, generators, radio, telecommunications and computing.
Facts
Central QuestionHow electric and magnetic phenomena, once studied separately, unify into a single electromagnetic force and field. 1 ScopeElectromagnetism studies the interaction between electrically charged particles through electromagnetic fields, one of the four fundamental forces of nature, spanning the related phenomena of electricity, magnetism and optics. 1 SignificanceThe electromagnetic force accounts for the attraction between atomic nuclei and electrons that holds atoms together, and underlies electrical, communication and computing technology. 1 Disputed
Founded YearHans Christian Orsted April 1820 demonstration that an electric current deflects a compass needle is the conventionally cited founding moment of electromagnetism as a unified field; Gian Romagnosi recorded the same effect independently in 1802, but it did not become widely known, so historians credit Orsted experiment as the effective founding, with Andre-Marie Ampere mathematical treatment following the same year. Connections
Founded By
Source James Clerk Maxwell (MacTutor)
Has Theory
Source Maxwell's Equations (Wikipedia)
Uses
Ampere, Units Source International System of Units (Wikipedia)
The Wheatstone bridge is a null-balance circuit for precisely measuring an unknown electrical resistance, popularized by Charles Wheatstone in 1843 (Samuel Hunter Christie first described the circuit in 1833).
Sources
1. Electromagnetism (Wikipedia)
WikipediaLead section, definition sentence
electromagnetism is an interaction that occurs between particles with electric charge via electromagnetic fields. The electromagnetic force is one of the four fundamental forces of nature.
Lead section, scope sentence
Electromagnetism describes and relates the three distinct but closely intertwined phenomena of electricity, magnetism, and optics.
Lead section, closing sentence
The electrostatic attraction between atomic nuclei and their electrons holds atoms together.
History, 19th century
In April 1820, Hans Christian Ørsted observed that an electrical current in a wire caused a nearby compass needle to move.
View the Source James Clerk Maxwell (MacTutor)
MacTutor History of Mathematics, University of St AndrewsFounded By: James Clerk Maxwell, Biography sectionQuote, Founded By: James Clerk Maxwell, Biography section
One of Maxwell's most important achievements was his extension and mathematical formulation of Michael Faraday's theories of electricity and magnetic lines of force.
Maxwell's Equations (Wikipedia)
WikipediaHas Theory: Maxwell's Equations, Lead sectionQuote, Has Theory: Maxwell's Equations, Lead section
Together with the Lorentz force law, they form the foundation of classical electromagnetism, classical optics, electric and magnetic circuits.
International System of Units (Wikipedia)
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