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optical activity

(Encyclopedia)optical activity, the ability of asymmetric compounds to rotate the orientation of planar polarized light. Such compounds and their mirror images are know as enantiomers, or optical isomers. Although ...

Fresnel, Augustin Jean

(Encyclopedia)Fresnel, Augustin Jean ōgüstăNˈ zhäN frānĕlˈ [key] 1788–1827, French physicist and engineer. He is known for his research on light, especially on conditions governing interference phenomena ...

photoelectric cell

(Encyclopedia)CE5 Photoelectric cell: Light causes a photosensitive surface to emit electrons, which flow as current to the positive terminal. A galvanometer measures the current and thus indicates light intensi...

relativity

(Encyclopedia)relativity, physical theory, introduced by Albert Einstein, that discards the concept of absolute motion and instead treats only relative motion between two systems or frames of reference. One consequ...

interference

(Encyclopedia)CE5 Constructive interference: Two crests or two troughs meet and combine (A, B, C). Destructive interference: A crest and a trough meet and cancel each other (D, E, F). interference, in physics, ...

diffraction

(Encyclopedia)diffraction, bending of waves around the edge of an obstacle. When light strikes an opaque body, for instance, a shadow forms on the side of the body that is shielded from the light source. Ordinarily...

photochemistry

(Encyclopedia)photochemistry, study of chemical processes that are accompanied by or catalyzed by the emission or absorption of visible light or ultraviolet radiation. A molecule in its ground (unexcited) state can...

Rogers, Richard George, Baron Rogers of Riverside

(Encyclopedia)Rogers, Richard George, Baron Rogers of Riverside, 1933–2021, British architect, b. Florence, Italy, Architectural Association, London (A.A. Dipl....

bioluminescence

(Encyclopedia)bioluminescence bīˌōlo͞oˌmĭnĕsˈəns [key], production of light by living organisms. Organisms that are bioluminescent include certain fungi and bacteria that emit light continuously. The dinof...

aesthetics

(Encyclopedia)aesthetics ĕsthĕtˈĭks [key], the branch of philosophy that is concerned with the nature of art and the criteria of artistic judgment. The classical conception of art as the imitation of nature was...