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infrared radiation

(Encyclopedia)infrared radiation, electromagnetic radiation having a wavelength in the range from c.75 × 10−6 cm to c.100,000 × 10−6 cm (0.000075–0.1 cm). Infrared rays thus occupy that part of the electrom...

Kirchhoff, Gustav Robert

(Encyclopedia)Kirchhoff, Gustav Robert go͝osˈtäf rōˈbĕrt kĭrkhˈhôf [key], 1824–87, German physicist. He served as professor of physics at the universities of Breslau (1850–54), Heidelberg (1854–74), ...

Granit, Ragnar

(Encyclopedia)Granit, Ragnar, 1900–1991, Swedish physiologist, M.D., Univ. of Helsinki, 1927. A professor at the Univ. of Helsinki from 1927, he joined the faculty of the Karolinska Institute, Sweden, in 1940. Gr...

spectroheliograph

(Encyclopedia)spectroheliograph, device for photographing the surface of the sun in a single wavelength of light, usually one corresponding to a chief element contained in the sun, e.g., hydrogen or calcium; the re...

red shift

(Encyclopedia)red shift or redshift, in astronomy, the systematic displacement of individual lines in the spectrum of a celestial object toward the red, or longer wavelength, end of the visible spectrum. The effect...

flame test

(Encyclopedia)flame test, test used in the identification of certain metals. It is based on the observation that light emitted by any element gives a unique spectrum when passed through a spectroscope. When a salt ...

sunburn

(Encyclopedia)sunburn, inflammation of the skin caused by actinic rays from the sun or artificial sources. Moderate exposure to ultraviolet radiation is followed by a red blush, but severe exposure may result in bl...

ultraviolet astronomy

(Encyclopedia)ultraviolet astronomy, study of celestial objects by means of the ultraviolet radiation they emit, in the wavelength range from about 90 to about 350 nanometers. Ultraviolet (UV) line spectrum measure...

Herzberg, Gerhard

(Encyclopedia)Herzberg, Gerhard gĕrˈhärt hûrtsˈbûrg [key], 1904–99, Canadian physicist, b. Hamburg, Germany. He studied at Darmstadt, Göttingen, and Bristol, England, receiving a doctorate in engineering p...

Cornu, Marie Alfred

(Encyclopedia)Cornu, Marie Alfred märēˈ älfrĕdˈ kôrnüˈ [key], 1841–1902, French physicist. From 1867 he was professor at the École polytechnique, Paris. He measured the velocity of light and made import...