Physical Constants

see also Units and Conversions

Symbol Value Description
q 1.602 × 10-19 coulomb electronic charge
q 1.602 × 10-19 conversion from joules to eV
m0 9.108 × 10-31 kg electron rest mass
c 2.99792458 × 108 m/s speed of light in vacuum
ε0 8.85418 × 10-14 farad/cm
8.85418 × 10-12 farad/m
permittivity of free space
h 6.62606957 × 10-27 erg·s
6.62606957 × 10-34 joule·s
Planck's constant
k 1.3806488 × 10-16 erg/K
1.3806488 × 10-23 joule/K
Boltzmann's constant
σ 5.67 × 10-8 J/m2s K4 Stefan-Boltzmann constant
kT/q 0.02586 V thermal voltage at 300 K
λ0 wavelength of 1 eV photon 1.24 μm