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Hans Christian Ørsted (/ ˈ ɜːr s t ɛ d /; [5] Danish: [ˈhænˀs ˈkʰʁestjæn ˈɶɐ̯steð] ⓘ; often rendered Oersted in English; [note 1] 14 August 1777 – 9 March 1851) was a Danish physicist and chemist who discovered that electric currents create magnetic fields. This phenomenon is known as Oersted's law. He also discovered ...
In electromagnetism, Ørsted's law, also spelled Oersted's law, is the physical law stating that an electric current induces a magnetic field. [ 2 ] This was discovered on 21 April 1820 by Danish physicist Hans Christian Ørsted (1777–1851), [ 3 ] [ 4 ] when he noticed that the needle of a compass next to a wire carrying current turned so ...
In the first half of the 19th century many very important additions were made to the world's knowledge concerning electricity and magnetism. For example, in 1820 Hans Christian Ørsted of Copenhagen discovered the deflecting effect of an electric current traversing a wire upon a suspended magnetic needle. [11]
He shows that a coil of wire carrying a current behaves like an ordinary magnet and suggests that electromagnetism might be used in telegraphy. He mathematically develops Ampère's law describing the magnetic force between two electric currents. His mathematical theory explains known electromagnetic phenomena and predicts new ones.
Magnetic poles (or states of polarization at individual points) attract or repel one another in a manner similar to positive and negative charges and always exist as pairs: every north pole is yoked to a south pole. [8] An electric current inside a wire creates a corresponding circumferential magnetic field outside the wire.
In 1845, Faraday discovered that many materials exhibit a weak repulsion from a magnetic field: an effect he termed diamagnetism. [ 65 ] Faraday also discovered that the plane of polarization of linearly polarised light can be rotated by the application of an external magnetic field aligned with the direction in which the light is moving.
The electric motor exploits an important effect of electromagnetism: a current through a magnetic field experiences a force at right angles to both the field and current. This relationship between magnetic fields and currents is extremely important, for it led to Michael Faraday's invention of the electric motor in 1821.
[15] [16] Maxwell's extension to the law states that a time-varying electric field can also generate a magnetic field. [12] Similarly, Faraday's law of induction states that a magnetic field can produce an electric current. For example, a magnet pushed in and out of a coil of wires can produce an electric current in the coils which is ...