Physical Constants
Constant
Symbol
Numerical value (new SI units) Unit
Speed of light in vacuum c 0
2.99792458 × 10
8 (exact)
m s
−1
Permeability of vacuum μ 0
4π × 10
−7
N A
−2
Permittivity of vacuum
0
(μ 0 c
2
0 )
−1
8.854187817 × 10
−12
F m
−1
Elementary charge
e
1.602176634 × 10
−19 (exact)
C
Electron mass
m e
9.1093837 × 10
−31
kg
Planck constant
h
6.62607015 × 10
−34 (exact)
J s
h/(2π)
1.05457182 × 10
−34
J s
6.58211957 × 10
−16
eV s
Boltzmann constant
k B
1.380649 × 10
−23 (exact)
J K
−1
8.6173333 × 10
−5
meV K
−1
von-Klitzing constant
R K h/e
2
25812.8075
Rydberg constant
13.605693123
eV
Bohr radius
a B
5.29177211 × 10
−11
m
Avogadro constant
N A
6.02214076 × 10
23 (exact)
mol
−1
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