SI photometry units
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Quantity | Symbol | SI unit | Symbol | Dimension | Notes | |||
---|---|---|---|---|---|---|---|---|
Luminous energy | Qv | lumen second | lm⋅s | T⋅J | units are sometimes called talbots | |||
Luminous flux | Φv | lumen (= cd⋅sr) | lm | J | also called luminous power | |||
Luminous intensity | Iv | candela (= lm/sr) | cd | J | an SI base unit, luminous flux per unit solid angle | |||
Luminance | Lv | candela per square metre | cd/m2 | L−2⋅J | units are sometimes called nits | |||
Illuminance | Ev | lux (= lm/m2) | lx | L−2⋅J | used for light incident on a surface | |||
Luminous emittance | Mv | lux (= lm/m2) | lx | L−2⋅J | used for light emitted from a surface | |||
Luminous exposure | Hv | lux second | lx⋅s | L−2⋅T⋅J | ||||
Luminous energy density | ωv | lumen second per metre3 | lm⋅s⋅m−3 | L−3⋅T⋅J | ||||
Luminous efficacy | η | lumen per watt | lm/W | M−1⋅L−2⋅T3⋅J | ratio of luminous flux to radiant flux | |||
Luminous efficiency | V | 1 | also called luminous coefficient | |||||
See also: SI · Photometry · Radiometry |
Read more about this topic: Lux
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