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amplitude

(Encyclopedia)amplitude ămˈplĭto͞odˌ [key], in physics, maximum displacement from a zero value or rest position. In the harmonic motion of a pendulum, the amplitude of the swing is the greatest distance reache...

electrodynamics

(Encyclopedia)electrodynamics, study of phenomena associated with charged bodies in motion and varying electric and magnetic fields (see charge; electricity); since a moving charge produces a magnetic field, electr...

Flavin, Dan

(Encyclopedia)Flavin, Dan flāˈvĭn [key], 1933–96, American sculptor, b. New York City. In the early 1960s, Flavin experimented with fluorescent lights, bending them into complex, angular shapes. His sculptures...

quartzite

(Encyclopedia)quartzite, usually metamorphic rock composed of firmly cemented quartz grains. Most often it is white, light gray, yellowish, or light brown, but is sometimes colored blue, green, purple, or black by ...

complementarity principle

(Encyclopedia)complementarity principle, physical principle enunciated by Niels Bohr in 1928 stating that certain physical concepts are complementary. If two concepts are complementary, an experiment that clearly i...

Lucifer

(Encyclopedia)Lucifer lo͞oˈsĭfər [key] [Lat.,=light-bearing], in Christian tradition a name for Satan. In the Vulgate, Lucifer served as a translation of the Hebrew epithet meaning “Day Star,” a name associ...

Edison, Thomas Alva

(Encyclopedia)Edison, Thomas Alva, 1847–1931, American inventor, b. Milan, Ohio. A genius in the practical application of scientific principles, Edison was one of the greatest and most productive inventors of his...

ray, in physics

(Encyclopedia)ray, in physics, term denoting the straight line along which light or other form of radiation is propagated from its source. It generally refers to the line of propagation of waves but is also applied...

Doppler effect

(Encyclopedia)Doppler effect, change in the wavelength (or frequency) of energy in the form of waves, e.g., sound or light, as a result of motion of either the source or the receiver of the waves; the effect is nam...

nimbus, in art

(Encyclopedia)nimbus nĭmˈbəs [key], in art, the luminous disk or circle or other indication of light around the head of a sacred personage. It was used in Buddhist and other Asian art and by the early Greeks and...