Physics constants, like the mass of a proton or speed of light, are physical quantities with fixed numerical values. This list contains the most common physics constants:
Avogadro's Number: NA = 6.022 × 1023 mol–1
Boltzmann's constant: k = 1.380 × 10–23 J/K
Coulomb's constant: k = 8.99 × 109 N–m2/C2
Gas constant: R = 8.314 J/(mol–K)
Gravitational constant: G = 6.672 × 10–11 N–m2/kg2
Speed of light: c = 2.997 × 108 m/s
Charge of electron: e = 1.602 × 10–19 C
Mass of proton: mp = 1.672 × 10–27 kg
Mass of electron: me = 9.109 × 10–31 kg