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Electromagnetic or magnetic induction is the production of an electromotive force (emf) across an electrical conductor in a changing magnetic field. Michael Faraday is generally credited with the discovery of induction in 1831, and James Clerk Maxwell mathematically described it as Faraday's law of induction .
Radio-frequency induction (RF induction) is the use of a radio frequency magnetic field to transfer energy by means of electromagnetic induction in the near field. A radio-frequency alternating current is passed through a coil of wire that acts as the transmitter , and a second coil or conducting object, magnetically coupled to the first coil ...
Eddy currents in conductors of non-zero resistivity generate heat as well as electromagnetic forces. The heat can be used for induction heating. The electromagnetic forces can be used for levitation, creating movement, or to give a strong braking effect. Eddy currents can also have undesirable effects, for instance power loss in transformers.
Bioelectromagnetics, also known as bioelectromagnetism, is the study of the interaction between electromagnetic fields and biological entities. Areas of study include electromagnetic fields produced by living cells, tissues or organisms, the effects of man-made sources of electromagnetic fields like mobile phones, and the application of electromagnetic radiation toward therapies for the ...
Maxwell's equations may be combined to demonstrate how fluctuations in electromagnetic fields (waves) propagate at a constant speed in vacuum, c (299 792 458 m/s [2]). Known as electromagnetic radiation, these waves occur at various wavelengths to produce a spectrum of radiation from radio waves to gamma rays.
When the flux changes—because B changes, or because the wire loop is moved or deformed, or both—Faraday's law of induction says that the wire loop acquires an emf, defined as the energy available from a unit charge that has traveled once around the wire loop.
A diagram of the electromagnetic spectrum, showing various properties across the range of frequencies and wavelengths. The electromagnetic spectrum is the full range of electromagnetic radiation, organized by frequency or wavelength. The spectrum is divided into separate bands, with different names for the electromagnetic waves within each band.
The cells are on a scale that is magnitudes larger than the atom, yet much smaller than the radiated wavelength, [3] [4] are on the order of nanometers. [ 3 ] [ 4 ] [ 5 ] In a conventional material, the response to electric and magnetic fields, and hence to light , is determined by atoms .