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| ==Origin== | | ==Origin== |
| West Frisian ''sinneljacht'', Middle Dutch ''sonnelicht'', (Dutch ''zonlicht''), Old High German ''sunnalioht'' and ''sunnûn lioht'' | | West Frisian ''sinneljacht'', Middle Dutch ''sonnelicht'', (Dutch ''zonlicht''), Old High German ''sunnalioht'' and ''sunnûn lioht'' |
− | *[http://en.wikipedia.org/wiki/13th_century 13th Century] | + | *[https://en.wikipedia.org/wiki/13th_century 13th Century] |
| ==Definition== | | ==Definition== |
| 1 : the [[light]] of the [[sun]] : sunshine | | 1 : the [[light]] of the [[sun]] : sunshine |
| ==Description== | | ==Description== |
− | '''Sunlight''', in the broad sense, is the total [[frequency]] [[spectrum]] of [[electromagnetic]] radiation given off by the [[Sun]], particularly [http://en.wikipedia.org/wiki/Infrared infrared], visible, and [http://en.wikipedia.org/wiki/Ultraviolet ultraviolet] light. On [[Earth]], sunlight is filtered through the [[Earth]]'s [[atmosphere]], and solar [[radiation]] is obvious as daylight when the Sun is above the [[horizon]]. | + | '''Sunlight''', in the broad sense, is the total [[frequency]] [[spectrum]] of [[electromagnetic]] radiation given off by the [[Sun]], particularly [https://en.wikipedia.org/wiki/Infrared infrared], visible, and [https://en.wikipedia.org/wiki/Ultraviolet ultraviolet] light. On [[Earth]], sunlight is filtered through the [[Earth]]'s [[atmosphere]], and solar [[radiation]] is obvious as daylight when the Sun is above the [[horizon]]. |
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| When the direct solar radiation is not blocked by [[clouds]], it is experienced as sunshine, a combination of bright [[light]] and radiant [[heat]]. When it is blocked by the clouds or [[reflects]] off of other objects, it is experienced as [[diffused]] light. | | When the direct solar radiation is not blocked by [[clouds]], it is experienced as sunshine, a combination of bright [[light]] and radiant [[heat]]. When it is blocked by the clouds or [[reflects]] off of other objects, it is experienced as [[diffused]] light. |
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− | The [http://en.wikipedia.org/wiki/World_Meteorological_Organization World Meteorological Organization] uses the term "sunshine duration" to mean the cumulative [[time]] during which an area receives direct irradiance from the [[Sun]] of at least 120 watts per square meter. | + | The [https://en.wikipedia.org/wiki/World_Meteorological_Organization World Meteorological Organization] uses the term "sunshine duration" to mean the cumulative [[time]] during which an area receives direct irradiance from the [[Sun]] of at least 120 watts per square meter. |
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− | Sunlight may be recorded using a [http://en.wikipedia.org/wiki/Sunshine_recorder sunshine recorder], [http://en.wikipedia.org/wiki/Pyranometer pyranometer] or [http://en.wikipedia.org/wiki/Pyrheliometer pyrheliometer]. Sunlight takes about 8.3 minutes to reach the Earth. | + | Sunlight may be recorded using a [https://en.wikipedia.org/wiki/Sunshine_recorder sunshine recorder], [https://en.wikipedia.org/wiki/Pyranometer pyranometer] or [https://en.wikipedia.org/wiki/Pyrheliometer pyrheliometer]. Sunlight takes about 8.3 minutes to reach the Earth. |
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| On [[average]], it takes energy between 10,000 and 170,000 years to leave the [[sun]]'s interior and then be emitted from the [[surface]] as [[light]]. | | On [[average]], it takes energy between 10,000 and 170,000 years to leave the [[sun]]'s interior and then be emitted from the [[surface]] as [[light]]. |
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− | Direct sunlight has a luminous efficacy of about 93 lumens per watt of [http://en.wikipedia.org/wiki/Radiant_flux radiant flux]. Bright sunlight provides illuminance of approximately 100,000 lux or lumens per square meter at the Earth's surface. | + | Direct sunlight has a luminous efficacy of about 93 lumens per watt of [https://en.wikipedia.org/wiki/Radiant_flux radiant flux]. Bright sunlight provides illuminance of approximately 100,000 lux or lumens per square meter at the Earth's surface. |
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− | Sunlight is a key factor in [http://en.wikipedia.org/wiki/Photosynthesis photosynthesis], a [[process]] vital for many living [[beings]] on [[Earth]].[http://en.wikipedia.org/wiki/Sunlight] | + | Sunlight is a key factor in [https://en.wikipedia.org/wiki/Photosynthesis photosynthesis], a [[process]] vital for many living [[beings]] on [[Earth]].[https://en.wikipedia.org/wiki/Sunlight] |
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| [[Category: Physics]] | | [[Category: Physics]] |