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Rv. The "J" has been too big a source of confusion for readers. See talk page.
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! <small>Name</small>
! <small>Name</small>
! <small>Symbol</small>
! <small>Symbol</small>
! <small>Symbol</small>
! <small>Symbol</small>{{#tag:ref|The symbols in this column denote [[Dimension of a physical quantity|dimension]]s; "'''L'''", "'''T'''" and "'''J'''" are for length, time and luminous intensity respectively, not the symbols for the [[Units of measurement|unit]]s litre, tesla and joule.|group={{#if:{{{3|}}}|{{{3}}}|nb}}|name=note-dimension-symbol}}<!-- [[http://www.bipm.org/utils/common/pdf/si_brochure_8.pdf]] [[http://www.ptb.de/cms/fileadmin/internet/publikationen/DasInternationaleEinheitensystem.pdf]] -->
|-
|-
| [[Luminous energy]]
| [[Luminous energy]]
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| [[lumen second]]
| [[lumen second]]
| [[lumen (unit)|lm]]⋅s
| [[lumen (unit)|lm]]⋅s
| '''T'''⋅'''J'''&nbsp;{{#tag:ref|"'''J'''" here is the symbol for the [[Dimension of a physical quantity|dimension]] of luminous intensity, not the symbol for the [[Units of measurement|unit]] joule.|group={{#if:{{{3|}}}|{{{3}}}|nb}}|name=note-dimension-J}}<!-- [[http://www.bipm.org/utils/common/pdf/si_brochure_8.pdf]] [[http://www.ptb.de/cms/fileadmin/internet/publikationen/DasInternationaleEinheitensystem.pdf]] -->
| '''T'''⋅'''J'''
| The lumen second is sometimes called the ''talbot''.
| The lumen second is sometimes called the ''talbot''.
|-
|-
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| [[lumen (unit)|lumen]] (=&nbsp;cd⋅[[steradian|sr]])
| [[lumen (unit)|lumen]] (=&nbsp;cd⋅[[steradian|sr]])
| lm
| lm
| '''J'''&nbsp;{{#tag:ref||group={{#if:{{{3|}}}|{{{3}}}|nb}}|name=note-dimension-J}}
| '''J'''
| Luminous energy per unit time
| Luminous energy per unit time
|-
|-
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| [[candela]] (=&nbsp;lm/sr)
| [[candela]] (=&nbsp;lm/sr)
| [[candela|cd]]
| [[candela|cd]]
| '''J'''&nbsp;{{#tag:ref||group={{#if:{{{3|}}}|{{{3}}}|nb}}|name=note-dimension-J}}
| '''J'''
| Luminous flux per unit [[solid angle]]
| Luminous flux per unit [[solid angle]]
|-
|-

Revision as of 07:10, 15 December 2017

Quantity Unit Dimension Notes
Name Symbol[nb 1] Name Symbol Symbol
Luminous energy Qv [nb 2] lumen second lm⋅s TJ [nb 3] The lumen second is sometimes called the talbot.
Luminous flux / luminous power Φv [nb 2] lumen (= cd⋅sr) lm J [nb 3] Luminous energy per unit time
Luminous intensity Iv candela (= lm/sr) cd J [nb 3] Luminous flux per unit solid angle
Luminance Lv candela per square metre cd/m2 L−2J Luminous flux per unit solid angle per unit projected source area. The candela per square metre is sometimes called the nit.
Illuminance Ev lux (= lm/m2) lx L−2J Luminous flux incident on a surface
Luminous exitance / luminous emittance Mv lux lx L−2J Luminous flux emitted from a surface
Luminous exposure Hv lux second lx⋅s L−2TJ Time-integrated illuminance
Luminous energy density ωv lumen second per cubic metre lm⋅s⋅m−3 L−3TJ
Luminous efficacy η [nb 2] lumen per watt lm/W M−1L−2T3J Ratio of luminous flux to radiant flux or power consumption, depending on context
Luminous efficiency / luminous coefficient V 1 Luminous efficacy normalized by the maximum possible efficacy
See also: SI · Photometry · Radiometry
  1. ^ Standards organizations recommend that photometric quantities be denoted with a suffix "v" (for "visual") to avoid confusion with radiometric or photon quantities. For example: USA Standard Letter Symbols for Illuminating Engineering USAS Z7.1-1967, Y10.18-1967
  2. ^ a b c Alternative symbols sometimes seen: W for luminous energy, P or F for luminous flux, and ρ or K for luminous efficacy.
  3. ^ a b c "J" here is the symbol for the dimension of luminous intensity, not the symbol for the unit joule.