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Michael Faraday holding a piece of glass of the type he used to demonstrate the effect of magnetism on polarization of light, c. 1857.. By 1845, it was known through the work of Augustin-Jean Fresnel, Étienne-Louis Malus, and others that different materials are able to modify the direction of polarization of light when appropriately oriented, [4] making polarized light a very powerful tool to ...
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.
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 ...
The magnetic field (marked B, indicated by red field lines) around wire carrying an electric current (marked I) Compass and wire apparatus showing Ørsted's experiment (video [1]) In electromagnetism , Ørsted's law , also spelled Oersted's law , is the physical law stating that an electric current induces a magnetic field .
He left a detailed account of his research under the title of Experiments on the Origin of Electricity. [30] He discovered electrified bodies attracted light substances in a vacuum, indicating the electrical effect did not depend upon the air as a medium. He also added resin, and other substances, to the then known list of electrics. [11] [31 ...
A current is induced in a loop of wire when it is moved toward or away from a magnetic field, or a magnet is moved towards or away from it; the direction of current depends on that of the movement. [9] In April 1820, Hans Christian Ørsted observed that an electrical current in a wire caused a nearby compass needle to move. At the time of ...
The weakness of the wave theory was that light waves, like sound waves, would need a medium for transmission. The existence of the hypothetical substance luminiferous aether proposed by Huygens in 1678 was cast into strong doubt in the late nineteenth century by the Michelson–Morley experiment .
These experiments established that light and these waves were both a form of electromagnetic radiation obeying the Maxwell equations. [ 22 ] Hertz's directional spark transmitter (center) , a half-wave dipole antenna made of two 13 cm brass rods with spark gap at center (closeup left) powered by a Ruhmkorff coil , on focal line of a 1.2 m x 2 m ...