electromagneticadj.
/ᵻˌlɛktrə(ʊ)maɡˈnɛtɪk/, U.S. /əˌlɛktrəˌmæɡˈnɛdɪk/, /iˌlɛktrəˌmæɡˈnɛdɪk/ Physics.
1. Relating to the interrelation of electric currents or fields and magnetic fields; having both electric and magnetic aspects or properties; (of devices, equipment, etc.) utilizing the phenomena of electromagnetism.
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the world > matter > physics > electromagnetic radiation > electricity > electrically induced magnetism > [adjective]
electromagnetic1820
electromagnetical1821
electric-magnetic1823
magneto-electric1831
magnelectric1832
machine-electric1833
magneto-electrical1836
Maxwellian1886
1820 tr. H. C. Oersted in Ann. Philos. 16 375 (title) New electro-magnetic experiments.
1821 H. Davy in Philos. Trans. (Royal Soc.) 111 7 He seems to have had some vague notion that electrical combinations, when not exhibiting their electrical tension, were in a magnetic state, and that there was a kind of electro-magnetic meridian depending upon the electricity of the earth.
1823 J. Badcock Domest. Amusem. 126 The electro-magnetic influence always increased with the number of the plates.
1837 Ann. Electr., Magnetism, & Chem. 1 387 We need scarcely despair of seeing the electro-magnetic telegraph established for regular communication from one town to another.
1870 J. Tyndall Lect. Electr. 4 The attraction exerted by electro-magnetic cores or bars of iron.
1930 Engineering 6 June 724/3 Three systems were in use, operated, respectively, by hydraulic, pneumatic and electro-magnetic (eddy currents in the wheels) means.
1958 J. Kerouac Let. 24 July in Sel. Lett. 1957–69 (1999) 143 I have no facts to back it up, like Einstein dont [sic] have no facts to back up what Buddha knew in full (electromagnetic-gravitational ecstasy).
1974 V. B. Mountcastle et al. Med. Physiol. (ed. 13) II. xli. 998/1 Coronary flow has also been measured by very small electromagnetic flowmeter probes in conscious animals.
2006 Wired Sept. 44 The devices reveal underground anomalies by detecting minute changes in the electromagnetic signatures of rock, clay, and sand.
2. Designating a unit of measurement in a system based on the force between two magnetic poles, or (equivalently) between two current-carrying wires, and an arbitrary assignment of value to the permeability of free space. Contrasted with electrostatic adj. 2.From the cgs electromagnetic system was developed the practical system (cf. practical adj. 1c), by multiplying the unit of current by 10−1 (giving the ampere) and the unit of potential by 108 (giving the volt). From the practical system was formed the MKSA system by adding the ampere (or the coulomb) as a fourth base unit, and this system formed the basis of the SI when it was established in 1957 (by adding units for temperature and luminosity).
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1853 W. Thomson in London, Edinb., & Dublin Philos. Mag. 4th Ser. 5 403 Results..enable us to determine the numerical relation between electro-statical and electro-magnetic units.
1886 J. D. Everett Units & Physical Constants (ed. 2) xi. 151 The Farad..is defined as 10−9 of the C.G.S. electro-magnetic unit of capacity.
1935 C. J. Smith Intermediate Physics (ed. 2) v. xliv. 716 When the magnitude of the current flowing in a closed circuit is numerically equal to the strength of its equivalent magnetic shell, that number represents the magnitude of the current in electromagnetic units.
1968 M. S. Livingston Particle Physics xii. 208 In the rationalized mks system of electromagnetic units, charge becomes a fourth fundamental quantity.
1988 H. A. Klein Sci. Measurem. xxxviii. 481 The name ‘oersted’ was given only in 1930 to the unit for magnetic field strength (H ) in the cgs-emu (electromagnetic) and Gaussian systems.
1994 J. Mehra Beat of Different Drum iii. 50 He had to measure the ratio of electrostatic and electromagnetic units, which he knew was related to the speed of light in a vacuum.
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electromagnetic energy n.
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1834 P. M. Cunningham Motions Earth & Heavenly Bodies i. 94 The above progressive diminution of electro-magnetic energy in the earth.
1913 L. Silberstein Vectorial Mech. i. 45 The flux of electromagnetic energy, per unit time and unit area, i.e. the so-called Poynting-vector.
2002 Maxim June 38/3 Superpotential theory is the manipulation of electromagnetic energy to cause temperature change.
electromagnetic field n.
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1864 J. C. Maxwell in Proc. Royal Soc. 1863–4 13 531 (title) A dynamical theory of the electromagnetic field.
1920 A. S. Eddington Space, Time & Gravitation ix. 149 The law of gravitation, the laws of mechanics, and the laws of the electromagnetic field have all been summed up in a single Principle of Least Action.
1997 D. Park Fire within Eye x. 334 Light..is a sensory experience, it is a medium of perception, and physicists call it a quantized electromagnetic field.
electromagnetic theory n.
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1830 Edinb. New Philos. Jrnl. 9 97 In the long interval between my [sc. Humboldt's] two journeys, the physical sciences, and especially geognosy, chemistry, and the electro-magnetic theory, have undergone considerable changes.
1928 Lancet 8 Dec. 1196/1 From that belief..we owe the whole electro-magnetic theory of light and ‘wireless’, electroplating, electrotyping, electrolysis, and innumerable other ‘everyday’ processes.
1990 Sci. Amer. June 82/3 Heaviside..regarded the electromagnetic theory as ‘obviously true’ on the strength of its mathematics alone.
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electromagnetic coil n. a coil consisting of one or more conductors wound around a magnetic or magnetizable core (as in an electromagnet).
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1841 London, Edinb., & Dublin Philos. Mag. 19 141 The proportion between the resistances of the electro-magnetic coils and those of the other parts of the circuit.
1940 Rep. Progr. Physics 7 108 A two-stage projection microscope focusing the electron rays by means of iron-shielded electromagnetic coils of short focal length.
2001 I. Stewart & J. Cohen Wheelers 339 Ugly electromagnetic coils were spaced along the rails in a complex progression, designed to transfer as much momentum as possible while using the least amount of electrical power.
electromagnetic force n. the force exerted by an electric or magnetic field on a charged particle.The electromagnetic force is one of the four fundamental forces of nature, the other three being the strong force (see strong adj. 7g), the weak force (see weak adj. 12k), and the gravitational force.
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1828 Edinb. New Philos. Jrnl. 5 230 These points of comparison are required for the declination and inclination of the magnetic needle, as well as for the intensity of the electro-magnetic forces.
1905 Science 29 Sept. 395/2 The older theories..are based on the so-called action at a distance or on the instantaneous transmission of electromagnetic force.
1950 H. Alfvén Cosmical Electrodynamics iv. 76 This coupling between mechanical and electromagnetic forces produces a type of wave motion, called magneto-hydrodynamic waves.
2002 F. Close et al. Particle Odyssey iii. 35 They had also come to appreciate that the electromagnetic force, which binds electrically charged constituents together, is carried by the photon.
electromagnetic gun n. a gun which uses electromagnetic energy to propel a missile.
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1902 N.Y. Times 8 May 1/4 Prof. K. Birkeland, the Norwegian physicist, has been in Berlin recently for the purpose of demonstrating the powers of his electro-magnetic gun before a number of experts in electrical artillery.
1934 J. D. Carr Eight of Swords (1986) iv. 50 He..was always frustrating somebody's plot to pinch the plans of the latest electromagnetic gun.
1998 J. S. Lewis Worlds without End xviii. 208 Another type of electrical propulsion system involves firing metallic slugs out of an electromagnetic gun at extremely high speeds.
electromagnetic pulse n. a pulse of electromagnetic energy, esp. a powerful one emitted by a nuclear explosion or nuclear weapon; cf. EMP n. at E n.1 Initialisms.
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1899 Science 25 Aug. 239/2 During the discharge the wire becomes a radiator of electromagnetic pulses or waves, regardless of the spark radiation.
1905 E. Rutherford in Philos. Trans. (Royal Soc.) A. 204 208 There is now little doubt that the γ rays are electromagnetic pulses, similar to X rays.
1951 H. Israël in T. F. Malone Compend. Meteorol. 150 The electromagnetic pulses..originating from electric discharges in the atmosphere are investigated.
1984 J. Varley Demon (1987) 8 The resulting burst of gamma radiation produced an electromagnetic pulse..that blew out every telephone..and electric sheep-shearer from Woomera to Sydney.
2002 Daily Tel. 26 Aug. 11/1 The ‘radio frequency weapon’, or E-Bomb,..sends out a high-intensity radio wave with similar effects to the electromagnetic pulse from a nuclear blast.
electromagnetic radiation n. radiation in the form of electromagnetic waves; cf. electromagnetic wave n.Visible light, infrared waves, ultraviolet light, microwaves, gamma rays, and X-rays are all forms of electromagnetic radiation, differing from each other only in their wavelength and frequency.
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1891 Proc. Royal Soc. 1890 48 472 The Rumford Medal has been awarded to Professor H. Hertz for his work on Electro-magnetic Radiation.
1940 G. Gamow Birth & Death of Sun iii. 83 In the heavier elements,..neutrons entering the nucleus must get rid of their energy through electromagnetic radiation, and the nucleus emits hard γ-rays.
2003 Pop. Sci. May 92 (caption) The Humvee-mounted Active Denial System..can strike from at least one-third of a mile away, using a focused beam of electromagnetic radiation.
electromagnetic spectrum n. = spectrum n. 3b.
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1924 Science 16 May 443/1 The electromagnetic spectrum considered as a whole extending from radio waves down to the shortest gamma rays of radium is briefly discussed.
1961 L. V. Berkner & H. Odishaw Sci. in Space i. 3 If we add the radio-frequency window to the narrow light-wave window, the sum gives astronomy about twenty octaves..of the electromagnetic spectrum with which to investigate the universe.
1999 T. Pratchett et al. Sci. of Discworld xiv. 110 If we look at the sky in the radio part of the electromagnetic spectrum, we can often ‘see’ things that are not apparent using ordinary visible light.
electromagnetic wave n. a wave consisting of a travelling periodic fluctuation in both an electric and a magnetic field, these fields being at right angles to each other and to the direction of propagation of the wave; cf. electromagnetic radiation n.
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1883 Proc. Amer. Philos. Soc. 1882–3 20 424 The æthereal particles..‘subside’ spirally towards the poles, giving rise to Ampérian currents which account for Maxwell's identification of luminous and electromagnetic waves.
1929 E. Mallett Telegr. & Telephony xi. 281 Whenever an electric current changes in a circuit, energy in the form of electromagnetic waves is radiated away from the circuit.
1985 Times 27 Dec. 12/2 He might then have grasped that electromagnetic waves penetrate more deeply than armies.
2003 M. Haddon Curious Incident of Dog in Night-time 42 The gravity of a black hole is so big that even electromagnetic waves like light can't get out of it.
This entry has been updated (OED Third Edition, June 2008; most recently modified version published online March 2022).
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adj.1820