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Luminous flux is the amount of light that falls on a unit area at unit distance from a source of one candela.

In SI units, it is measured in lumen.

SI light units

SI light units edit  (http://www.wordiq.com/definition/Template:SI_light_units)
Quantity	SI unit	Symbol	Notes
Luminous energy	joule	J
Luminous flux	lumen or ( candela · steradian )	lm	also called Luminous power
Luminous intensity	candela	cd
Luminance	candela / square metre	cd/m2	also called Luminosity
Illuminance	lux or (lumen / square metre)	lx
Luminous efficacy	lumens per watt	lm/w

de:Lichtstrom