| electromagnetic radiation | <physics> Radiation (such as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays) which consists of associated, interacting electric and magnetic field waves which travel at the speed of light. All forms of electromagnetic radiation can be transmitted through vacuum. Electromagnetic waves in plasmas are generally more complex in their behaviour, depending on their frequency. (09 Oct 1997) |
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| electromagnetic | <physics> Of, Pertaining to, or produced by, magnetism which is developed by the passage of an electric current. Electromagnetic engine, an engine in which the motive force is electromagnetism. Electromagnetic theory of light, a theory of light which makes it consist in the rapid alternation of transient electric currents moving transversely to the direction of the ray. (03 Mar 1998) |
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| electromagnetic coupling | <physics> A means of extracting energy from a magnetically confined plasma, where the plasma expands and pushes on the confining magnetic field, causing electrical energy to be generated in the external field-generating circuits. (09 Oct 1997) |
| electromagnetic fields | Fields representing the joint interplay of electric and magnetic forces. (12 Dec 1998) |
| electromagnetic flowmeter | A flowmeter in which a magnetic field is applied to a blood vessel to measure flow in terms of the voltage developed by the blood as a conductor moving through the magnetic field. (05 Mar 2000) |
| electromagnetic force | <physics> One of the fundamental forces of interaction which influences charged entities. In quantum field theory, the electromagnetic force is mediated by particles of exchange called (virtual) photons. Photons are massless and travel at the speed of light c. The electromagnetic force obeys an inverse square law, which makes sense because it is mediated by particles that have an infinite lifetime (special-relativistically, time stops in a frame moving at c when observed from a non-moving frame). (05 Jan 1998) |
| electromagnetic induction | Electromagnetic waves propagated by induction in an electromagnetic field. (05 Mar 2000) |
| electromagnetic lens | <apparatus> An electromagnet designed to produce a suitably shaped magnetic field for the focusing and deflection of electrons or other charged particles in electron optical instruments (cf. Electrostatic lens.) See: microscope, electron. (05 Aug 1998) |
| electromagnetic unit | The unit in an absolute system (CGS) of unit's utilizing the magnetic effects of current; e.g., abampere, abfarad, abhenry, abohm, abvolt. (05 Mar 2000) |
| electromagnetic wave | <physics> A wave of electric and magnetic fields that can move through space. Particles which make up the waves are called photons. (09 Oct 1997) |
| abnormalities, radiation-induced | Congenital changes in the morphology of organs produced by exposure to ionizing or non-ionizing radiation. (12 Dec 1998) |
| accidents, radiation | Accidental dispersal of radioactive materials from a radiation source. Accidents at nuclear reactors can involve large groups of the population from dispersion of radioactivity into the environment and through fallout or a few individuals with high injurious doses. (12 Dec 1998) |
| acoustic radiation | The fibres that pass from the medial geniculate body to the transverse temporal gyri of the cerebral cortex by way of the sublentiform part of the internal capsule. Synonym: radiatio acustica. (05 Mar 2000) |
| acute radiation syndrome | <syndrome> A syndrome caused by exposure of the body to large amounts of radiation, (e.g., from certain forms of therapy, accidents, and nuclear explosions; it is divided into three major forms which are, in ascending order of severity, the haematogic, gastrointestinal, and central nervous system-cardiovascular forms; its clinical manifestations are divided into prodromal, latent, overt, and recovery stages. (05 Mar 2000) |
| adaptive radiation | <chemistry> The evolution of new speciesor sub-species to fill unoccupied ecological niches. (06 May 1997) |
| alpha radiation | <physics, radiobiology> The most easily absorbable type of radiation, it consists of a stream of alpha particles, doubly ionised helium nuclei which are electrically charged and produce intense ionisation in matter. Alpha radiation can be deflected in electromagnetic fields. (09 Oct 1997) |