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%I A081820 #20 Jul 13 2022 19:07:58
%S A081820 5,6,7,0,3,7,4,4,1,9,1,8,4,4,2,9,4,5,3,9,7,0,9,9,6,7,3,1,8,8,9,2,3,0,
%T A081820 8,7,5,8,4,0,1,2,2,9,7,0,2,9,1,3,0,3,6,8,2,4,0,5,4,6,1,7,3,7,0,5,3,9,
%U A081820 4,8,1,6,0,6,2,6,5,2,3,3,2,6,0,8,2,5,7,1,8,5,7,7,7,0,4,4,6,8,8,7,0,3
%N A081820 Decimal expansion of the Stefan-Boltzmann constant sigma in the 2019 SI system in units Watt/(m^2*K^4).
%C A081820 From _Jeremy Tan_, Jun 13 2019: (Start)
%C A081820 The Stefan-Boltzmann law states that for a black body with temperature T, its radiant emittance j* (power radiated per unit area) is sigma * T^4.
%C A081820 In SI units, all the values in the defining relation in the Formula section are fixed as of May 20 2019 (see the BIPM link), so this constant is also fixed. (End)
%H A081820 BIPM, <a href="https://www.bipm.org/utils/common/pdf/CGPM-2018/26th-CGPM-Resolutions.pdf">On the revision of the International System of Units (SI)</a>, BIPM, Nov 13-16 2018.
%H A081820 NIST, <a href="http://physics.nist.gov/cgi-bin/cuu/Value?sigma">CODATA Value: Stefan-Boltzmann constant</a>
%H A081820 Wikipedia, <a href="https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant">Stefan-Boltzmann constant</a>
%H A081820 Wikipedia, <a href="https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law">Stefan-Boltzmann law</a>
%H A081820 <a href="/index/Na">Index entries for natural constants</a>
%H A081820 <a href="/index/Tra#transcendental">Index entries for transcendental numbers</a>
%F A081820 sigma = 5.6703744... * 10^-8 W m^-2 K^-4
%F A081820 Equals A222609*A070063^4/(A003676^3*A003678^2).
%t A081820 First@ RealDigits@ N[2 Pi^5 (1380649 10^-29)^4 / (15 (662607015 10^-42)^3 299792458^2), 120] (* _Jeremy Tan_, Jun 13 2019 *)
%Y A081820 Fixed SI constants used in deriving this constant: A003676 (h), A003678 (c), A070063 (k).
%K A081820 nonn,cons
%O A081820 -7,1
%A A081820 _Benoit Cloitre_, Apr 10 2003
%E A081820 Edited by _Andrey Zabolotskiy_, Jun 23 2017
%E A081820 Updated to 2019 SI by _Jeremy Tan_, Jun 13 2019

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