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ion, in chemistry

(Encyclopedia)ion, atom or group of atoms having a net electric charge. Ionization has many applications. Vapor lamps and fluorescent lamps take advantage of the light given off when positive ions recombine with ...

spectrum

(Encyclopedia)CE5 Dispersion of white light by a triangular prism spectrum, arrangement or display of light or other form of radiation separated according to wavelength, frequency, energy, or some other propert...

eye

(Encyclopedia)CE5 Cross section of human eye eye, organ of vision and light perception. In humans the eye is of the camera type, with an iris diaphragm and variable focusing, or accommodation. Other types of ey...

infrared astronomy

(Encyclopedia)infrared astronomy, study of celestial objects by means of the infrared radiation they emit, in the wavelength range from about 1 micrometer to about 1 millimeter. All objects, from trees and building...

Bismarck, Otto von

(Encyclopedia)Bismarck, Otto von bĭzˈmärk, Ger. ôˈtō fən bĭsˈmärk [key], 1815–98, German statesman, known as the Iron Chancellor. The Bismarckian era closed with the death of Emperor Frederick III. A ...

light

(Encyclopedia)light, visible electromagnetic radiation. Of the entire electromagnetic spectrum, the human eye is sensitive to only a tiny part, the part that is called light. The wavelengths of visible light range ...

Tibet

(Encyclopedia)Tibet tĭbĕtˈ [key], Tibetan Bodyul, Mandarin Xizang, autonomous region (2010 pop. 3,002,166), c.471,700 sq mi (1,221,700 sq km), SW China. A Chinese autonomous region since 1951, Tibet is bordered ...

calendar

(Encyclopedia)calendar [Lat., from Kalends], system of reckoning time for the practical purpose of recording past events and calculating dates for future plans. The calendar is based on noting ordinary and easily o...

Korea

(Encyclopedia)CE5 Korea kôrēˈə, kə– [key], Korean Hanguk or Choson, region and historic country (85,049 sq mi/220,277 sq km), E Asia. A peninsula, 600 mi (966 km) long, Korea separates the Sea of Japan (c...

London, city, England

(Encyclopedia)London, capital of Great Britain, SE England, on both sides of the Thames River. Greater London (1991 pop. 6,378,600), c.620 sq mi (1,610 sq km), consists of the Corporation of the City of London (199...