emitting medium
41climate — /kluy mit/, n. 1. the composite or generally prevailing weather conditions of a region, as temperature, air pressure, humidity, precipitation, sunshine, cloudiness, and winds, throughout the year, averaged over a series of years. 2. a region or… …
42optics — /op tiks/, n. (used with a sing. v.) the branch of physical science that deals with the properties and phenomena of both visible and invisible light and with vision. [1605 15; < ML optica < Gk optiká, n. use of neut. pl. of OPTIKÓS; see OPTIC,… …
43Electron — For other uses, see Electron (disambiguation). Electron Experiments with a Crookes tube first demonstrated the particle nature of electrons. In this illustration, the profile of the cross shaped target is projected against the tube face at right… …
44Messier 87 — Virgo A The Messier 87 galaxy. Observation data Epoch J2000 Constellation Virgo Right ascension …
45Megamaser — A megamaser is a type of astrophysical maser, which is a naturally occurring source of stimulated spectral line emission. Megamasers are distinguished from astrophysical masers by their large isotropic luminosity. Megamasers produce roughly 103… …
46Stage lighting instrument — Stage lighting instruments are used in stage lighting to illuminate theatrical productions, rock concerts and other performances taking place in live performance venues. They are also used to light television studios and sound stages.Terminology… …
47Sonar — This article is about underwater sound propagation. For atmospheric sounding, see SODAR. For other uses, see Sonar (disambiguation) …
48Photonics — Refraction of waves of photons (light) by a prism The science of photonics[1] includes the generation, emission, transmission, modulation, signal processing, switching …
49Corporate Average Fuel Economy — CAFE redirects here. For other uses, see Cafe (disambiguation). The Corporate Average Fuel Economy (CAFE) are regulations in the United States, first enacted by the U.S. Congress in 1975,[1] and intended to improve the average fuel economy of… …
50Video projector — Projected image from a video projector in a home cinema. A video projector is an image projector that receives a video signal and projects the corresponding image on a projection screen using a lens system. All video projectors use a very bright… …
