Table of Physical Constants

Commonly Used Constants

Need a value for a fundamental physical constant? Typically, these values are learned only on the short term as you are introduced to them and forgotten as soon as the test or task is finished. When they are needed again, constant searching through the textbook is one way to find the information again. A better way would be to us this handy reference table.

Commonly Used Physical Constants

 Constant Symbol Value acceleration due to gravity g 9.8 m s-2 atomic mass unit amu, mu or u 1.66 x10-27 kg Avogadro's Number N 6.022 x 1023 mol-1 Bohr radius a0 0.529 x 10-10 m Boltzmann constant k 1.38 x 10-23 J K-1 electron charge to mass ratio -e/me -1.7588 x 1011 C kg-1 electron classical radius re 2.818 x 10-15 m electron mass energy (J) mec2 8.187 x 10-14 J electron mass energy (MeV) mec2 0.511 MeV electron rest mass me 9.109 x 10-31 kg Faraday constant F 9.649 x 104 C mol-1 fine-structure constant α 7.297 x 10-3 gas constant R 8.314 J mol-1 K-1 gravitational constant G 6.67 x 10-11 Nm2kg-2 neutron mass energy (J) mnc2 1.505 x 10-10 J neutron mass energy (MeV) mnc2 939.565 MeV neutron rest mass mn 1.675 x 10-27 kg neutron-electron mass ratio mn/me 1838.68 neutron-proton mass ratio mn/mp 1.0014 permeability of a vacuum μ0 4π x 10-7 N A-2 permittivity of a vacuum ε0 8.854 x 10-12 F m-1 Planck constant h 6.626 x 10-34 J s proton mass energy (J) mpc2 1.503 x 10-10 J proton mass energy (MeV) mpc2 938.272 MeV proton rest mass mp 1.6726 x 10-27 kg proton-electron mass ratio mp/me 1836.15 Rydberg constant r∞ 1.0974 x 107 m-1 speed of light in vacuum C 2.9979 x 108 m/s