Luminous Flux
A photometric quantity measuring total perceived power of light emitted by a source, weighted by human eye spectral sensitivity.
Governing formula
Φ_v = 683 ∫ P(λ) V(λ) dλ
SI unit
Lumens (lm)
In depth
Weighted by the CIE photopic eye response curve $V(λ)$, which peaks at green light 555 nm ($683 lm/W$).
Examples in the real world
A 10-Watt modern LED bulb emitting approximately 800 to 1000 lumens of luminous flux.