The energy radiated by a light source in a unit of time to the surrounding space and makes the human eye produce light sensation.
Calculation formula: Φλ=683PλVλ
Where Φλ-wavelength λ of the luminous flux, lumens (lm);
P λ - radiant flux of wavelength λ (energy emitted by the radiation source in unit time, in W);
V λ - spectral luminous efficiency at a wavelength of λ;
683 - the larger spectral light efficiency, which for bright vision has a value of 683 lm/W at λ = 555 nm.
In case of multicolor light, its luminous flux is the sum of each monochromatic light, i.e. Φλn = Φλ1 + Φλ2 + ... = KmΣ[PλVλ]