Section 17

Physical constants

Constant	Symbol	Approximate value	Unit
Standard gravitational acceleration	$g_{0}$	$9.80665$	m/s²
Universal gravitational constant	$G$	$6.67430 \times 1 0^{- 11}$	N·m²/kg²
Speed of light	$c$	$2.99792458 \times 1 0^{8}$	m/s
Elementary charge	$e$	$1.602176634 \times 1 0^{- 19}$	C
Vacuum permittivity	$ε_{0}$	$\approx 8.854 \times 1 0^{- 12}$	F/m
Coulomb constant	$k_{e}$	$\approx 8.988 \times 1 0^{9}$	N·m²/C²
Boltzmann constant	$k_{B}$	$1.380649 \times 1 0^{- 23}$	J/K
Universal gas constant	$R$	$8.314462618...$	J/(mol·K)
Stefan–Boltzmann constant	$σ$	$\approx 5.6704 \times 1 0^{- 8}$	W/(m²·K⁴)