Values of Physical Constants  

Approximate Numerical Values > s.a. anthropic principle; solar planets; types of particles; units.
* Table: To three or four significant digits, the values of some of the most commonly used physical constants are:

Name Approximately
Avogadro's number NA = 6.022 × 1023 mol–1
Boltzmann's constant kB = 1.381 × 10–16 erg/K = 1.381 × 10–23 J/K
Electron charge e = 1.602 × 10–19 C
Fine-structure constant α = 1/137 = 0.007299
Gas constant R = 8.314 J · mol/K
Molar gas constant R = 1.987 cal/mol/K
Magnetic permeability μ0 = 4π × 10–7 N/A2
Newton's constant G = 6.674 × 10–8 cm3/g/s2
Permittivity of the vacuum ε0 = 8.854 × 10–12 C2/N/m2
Planck's constant h = 6.62607 × 10–27 erg · s = 6.62607 × 10–34 J · s
  \(\hbar\) = 1.05457 × 10–27 erg · s = 1.05457 × 10–34 J · s
Rydberg constant R = 1.097 × 105 cm–1
Speed of light c = 2.998 × 1010 m/s
Stefan-Boltzmann constant σ = 5.670 × 10–8 W/m2/K4
   
Particle Property Approximately
Electron mass me = 9.109 × 10–28 g = 511 keV/c2
Pion mass mπ = 139.6 MeV/c2±), 135.0 MeV/c20)
Kaon mass mK = 493.7 MeV/c2 (K±), 497.6 MeV/c2 (K0)
Nucleon mass mN = 1.67 × 10–24 g
   

@ References: Mohr & Taylor RMP(05) [2002 values]; Mohr et al RMP(12)-a1203 [2010 values].
> Online resources: NIST website; Particle Data Group website and PDG Live website.


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