Candela: Difference between revisions
From Glossary of Meteorology
imported>Perlwikibot (Created page with " {{TermHeader}} {{TermSearch}} <div class="termentry"> <div class="term"> == candela == </div> <div class="definition"><div class="short_definition">(Abbreviated cd.) A...") |
imported>Perlwikibot No edit summary |
||
| Line 9: | Line 9: | ||
</div> | </div> | ||
<div class="definition"><div class="short_definition">(Abbreviated cd.) A unit of [[luminous]] intensity expressed in [[lumen]] per [[steradian]] (lm sr<sup> | <div class="definition"><div class="short_definition">(Abbreviated cd.) A unit of [[luminous]] intensity expressed in [[lumen]] per [[steradian]] (lm sr<sup>-1</sup>).</div><br/> <div class="paragraph">The candela was first defined as 1/60 the luminous intensity, in the perpendicular direction, of a 1 cm<sup>2</sup> [[blackbody]] radiator at the [[freezing]] temperature of platinum (about 2042 K) and a [[pressure]] of 1 [[atmosphere]]. It is now defined as the luminous intensity of a [[light]] source producing single-frequency light at a [[frequency]] of 540 terahertz with a [[power]] of 1/683 [[watt]] per [[steradian]]. It is the [[standard]] unit of measure for luminous intensity adopted by the International System of Units (SI). In some texts, it is referred to as the international standard candle.</div><br/> </div> | ||
</div> | </div> | ||
Latest revision as of 13:47, 20 February 2012
candela
The candela was first defined as 1/60 the luminous intensity, in the perpendicular direction, of a 1 cm2 blackbody radiator at the freezing temperature of platinum (about 2042 K) and a pressure of 1 atmosphere. It is now defined as the luminous intensity of a light source producing single-frequency light at a frequency of 540 terahertz with a power of 1/683 watt per steradian. It is the standard unit of measure for luminous intensity adopted by the International System of Units (SI). In some texts, it is referred to as the international standard candle.
