candela

candela
(cd)
   the SI base unit for measuring the intensity of light. Candela is the Latin word for "candle."
   The unit has a long and complicated history. Originally, it represented the intensity of an actual candle, assumed to be burning whale tallow at a specified rate in grains per hour. Later this definition was replaced with a definition in terms of the light produced by the filament of an incandescent light bulb. Still later a standard was adopted that defined the candela as the intensity of 1/600 000 square meter of a "black body" (a perfect radiator of energy) at the temperature of freezing platinum (2042 K) and a pressure of 1 atmosphere.
   This definition has also been discarded, and the candela is now defined to be the luminous intensity of a light source producing single-frequency light at a frequency of 540 terahertz (THz) with a power of 1/683 watt per steradian, or 18.3988 milliwatts over a complete sphere centered at the light source. The frequency of 540 THz corresponds to a wave length of approximately 555.17 nanometers (nm); normal human eyes are more sensitive to the green light of this wavelength than to any other. In order to produce 1 candela of single-frequency light of wavelength l, a lamp would have to radiate 1/(683V(l)) watts per steradian, where V(l) is the relative sensitivity of the eye at wavelength l. Values of V(l), defined by the International Commission on Illumination (CIE), are available online from the Color and Vision Research Laboratories of the University of California at San Diego and the University of Tübingen, Germany.

Dictionary of units of measurement. 2015.

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  • Candéla — Candela Pour les articles homonymes, voir Candela (homonymie) …   Wikipédia en Français

  • candela — [ kɑ̃dela ] n. f. • 1949; mot lat. « chandelle » ♦ Phys. Unité d intensité lumineuse (symb.cd). Candela par mètre carré : unité de luminance lumineuse (cd/m 2). On écrirait mieux candéla. ● candela nom féminin …   Encyclopédie Universelle

  • candela — (Del lat. candēla). 1. f. vela (ǁ cilindro o prisma de cera). 2. candelero (ǁ para sostener velas). 3. Flor del castaño, de la encina o del alcornoque. 4. Claro que deja el fiel de la balanza cuando se inclina a la cosa que se pesa. 5. coloq.… …   Diccionario de la lengua española

  • candelă — CÁNDELĂ, candele, s.f. 1. Lampă cu ulei, care se pune la icoane sau la morminte sau care servea, în trecut, la iluminat. 2. Unitate de măsură pentru calcularea intensităţii unui izvor de lumină. 3. Stâlp rotund de lemn, întrebuinţat pentru… …   Dicționar Român

  • CANDELA (F.) — CANDELA FELIX (1910 ) Architecte mexicain d’origine espagnole. Né à Madrid où il fait ses études à l’École supérieure d’architecture, Candela émigre au Mexique en 1939 après avoir été interné dans un camp de réfugiés en France. Héritier spirituel …   Encyclopédie Universelle

  • Candela — Saltar a navegación, búsqueda Para otros usos de este término, véase Candela (desambiguación). candela Estándar: Unidades básicas del Sistema Internacional Magnitud: Intensidad luminosa Símbolo …   Wikipedia Español

  • CANDELA — quid proprie, vide infra, Lucerna. At pro lucerna olearia, apud recentioris aevi Scriptores passim; sicut κανδήλα Graecis usurpatur. Sophronius Patriarch. Hierosolymit Τοῦ τῆς κανδηλας ἐλάιου ἄνω πρὸ τῶ τοῦ Σωτῆρος ἐικόνος ἀπτο μένης λαβών. Et… …   Hofmann J. Lexicon universale

  • candela — sustantivo femenino 1. Cilindro de cera que sirve para alumbrar. Sinónimo: cirio, vela. 2. Lumbre, fuego: ¿Me das candela? 3. Área: física Unidad de intensidad luminosa …   Diccionario Salamanca de la Lengua Española

  • candela — /kan dela/ s.f. [lat. candēla, der. di candēre essere bianco, splendere ]. [cilindro di cera, stearina, sego, contenente un lucignolo di fibra vegetale che, acceso, dà fiamma e luce] ▶◀ (non com.) bugia, (non com.) moccolo, (region.) stearica.… …   Enciclopedia Italiana

  • candela — candela, repartir candela expr. pegar, golpear. ❙ «...frente de Teruel donde se repartía candela por todo lo alto.» Rafael García Serrano, Diccionario para un macuto …   Diccionario del Argot "El Sohez"

  • candela — n. the basic unit of luminous intensity adopted under the System International d Unites. Syn: candle, cd, standard candle. [WordNet 1.5] …   The Collaborative International Dictionary of English

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