OFFSET
-40,1
COMMENTS
The seven defining constants of the SI system (May 20 2019) are (see the BIPM link):
Δν_{Cs} = Δν(133Cs)_{hfs} = 9192631770 s^(-1)
c = 299792458 m/s
h = 6.62607015*10^{-34} J s [kg m^2 s^(-1)]
e = 1.602176634*10^{-19} C [A s]
k = 1.380649*10^{-23} J/K [kg m^2 s^(-2) K^(-1)]
N_A = 6.02214076*10{23} mol^(-1)
K_{cd} = 683 lm/W [cd sr s^3 kg^(-1) m^(-2)]
In brackets are the units given in s, m, kg, A, K, and cd*sr. The symbol sr stands for steradian (or sterad).
K_{cd} is the luminous efficacy of monochromatic radiation of frequency 540*10^12 Hz, with Hz = 1/s.
The given combination of three constants defines the kg from the Planck constant h after s and m have been expressed in terms of Delta nu_{Cs} and c.
LINKS
BIPM, On the revision of the International System of Units (SI), Nov 13-16 2018.
Max Planck, Ueber irreversible Strahlungsvorgänge, Ann. Physik 1 (1900) 69-122. See paragraph 26. Natürliche Maasseinheiten. pp. 120-122; alternative link.
Wikipedia, 2019 redefinition of SI base units
FORMULA
Equals 0.677726531231206761061727023465843553944645570624232398042662245... * 10^{-40} kg.
CROSSREFS
KEYWORD
AUTHOR
Wolfdieter Lang, Feb 11 2019
STATUS
approved