OFFSET
10,1
COMMENTS
For the seven units of the 2019 SI system of units see the BIPM link with the resolutions of the CGPM, and A322415.
The 2010 SI unit K_{cd} is the luminous efficacy of monochromatic radiation of frequency 540 x 10^{12} Hz, given by K_{cd} = 683 lm/W = 683 cd sr s^3 kg^{-1} m^{-2}, with the old SI unit cd and the derived unit sr = steradian.
LINKS
BIPM, CGPM-2018 [See the link "Resolutions of the CGPM" there.]
Wikipedia, 2019 redefinition of SI base units
FORMULA
1 lm = (1/638) K_{cd}*W = 1/(683*662607015*(9192631770)^2)*10^{42} K_{cd}*h*(Δν_{Cs})^2 = 2.614830482285615686376197193039854161436276883153653365272723... x 10^{10} K_{cd}*h*(Δν_{Cs})^2 .
CROSSREFS
KEYWORD
AUTHOR
Wolfdieter Lang, Feb 13 2019
STATUS
approved