lumen second

SI coherent derived unit whose name and symbol includes an SI coherent derived unit with a special name and symbol

Name	Symbol	Quantity	Base units
lumen second	lm s	luminous energy	s cd
The lumen second, symbol lm s, is the SI coherent derived unit of luminous energy, a measure of the total quantity of visible light emitted by a source.
Definition			h Δν_Cs K_cd
$1 \mspace{4mu} \text{lm} \mspace{4mu} \text{s} \mspace{6mu} = \dfrac{1}{(6.626 \mspace{4mu} 070 \mspace{4mu} 15 \times 10^{-34})(9 \mspace{4mu} 192 \mspace{4mu} 631 \mspace{4mu} 770)(683)} \mspace{6mu} h \mspace{4mu} \Delta \nu _{Cs} \mspace{4mu} K_{cd}\\ \\ \\ 1 \mspace{4mu} \text{lm} \mspace{4mu} \text{s} \mspace{6mu} \approx 2.403 \mspace{4mu} 717 \mspace{4mu} 376 \mspace{4mu} 462 \mspace{4mu} 317 \mspace{4mu} 297 \times10^{20} \mspace{6mu} h \mspace{4mu} \Delta \nu _{Cs} \mspace{4mu} K_{cd}$

Luminous energy

Luminous energy is a measure of the total quantity of visible light emitted by a source.

The lumen second is analogous to the watt second, or joule.

Luminous energy differs from radiant energy, in that radiant energy includes electromagnetic waves at all emitted frequencies, while luminous energy is weighted according to the human eye’s sensitivity to different frequencies, or wavelengths.

Photometry units

candela	cd	luminous intensity
lumen	lm	luminous flux
lux	lx	illuminance
candela per square metre	cd/m²	luminance
lumen second	lm s	luminous energy
lumen per watt	lm/W	luminous efficacy