Appendix C: Fundamental Constants
( \newcommand{\kernel}{\mathrm{null}\,}\)
Note: These constants are the values recommended in 2006 by CODATA, based on a least-squares adjustment of data from different measurements. The numbers in parentheses for the values represent the uncertainties of the last two digits.
* c is the speed of light
Quantity | Symbol | Value |
---|---|---|
Atomic mass unit | u | 1.660 538 782 (83) x 10−27 kg 931.494 028 (23) MeV/c2 * |
Avogadro’s number | NA | 6.022 141 79 (30) x 1023 particles/mol |
Bohr magneton | μB=eℏ2me | 9.274 009 15 (23) x 10−24 J/T |
Bohr radius | a0=ℏ2mee2ke | 5.291 772 085 9 (36) x 10−11 m |
Boltzmann’s constant | kB=RNA | 1.380 650 4 (24) x 10−23 J/K |
Compton wavelength | λC=hmec | 2.426 310 217 5 (33) x 10−12 m |
Coulomb constant | ke=14πε0 | 8.987 551 788... x 109 N • m2/C2 (exact) |
Deuteron mass | md | 9.109 382 15 (45) x 10−31 kg 5.485 799 094 3(23) x 10−4 u 0.510 998 910 (13) MeV/c2 * |
Electron mass | me | 9.109 382 15 (45) x 10−31 kg 5.485 799 094 3(23) x 10−4 u 0.510 998 910 (13) MeV/c2 * |
Electron volt | eV | 1.602 176 487 (40) x 10−19 J |
Elementary charge | e | 1.602 176 487 (40) x 10−19 C |
Gas constant | R | 8.314 472 (15) J/mol • K |
Gravitational constant | G | 6.674 28 (67) x 10−11 N • m2/kg2 |
Neutron mass | mn | 1.674 927 211 (84) x 10−27 kg 1.008 664 915 97 (43) u 939.565 346 (23) MeV/c2 * |
Nuclear magneton | μn=eℏ2mp | 5.050 783 24 (13) x 10−27 J/T |
Permeability of free space | μ0 | 4π x 10−7 T • m/A (exact) |
Permittivity of free space | ε0=1μ0c2 | 8.854 187 817... x 10−12 C2/N • m2 (exact) |
Planck’s constant | h | 6.626 068 96 (33) x 10−34 J • s |
Reduced Planck's constant | ℏ=h2π | 1.054 571 628 (53) x 10−34 J • s |
Proton mass | mp | 1.672 621 637 (83) x 10−27 kg 1.007 276 466 77 (10) u 938.272 013 (23) MeV/c2 * |
Rydberg constant | RH | 1.097 373 156 852 7 (73) x 107 m−1 |
Speed of light in vacuum | c | 2.997 924 58 x 108 m/s (exact) |
Useful combinations of constants for calculations:
- hc = 12,400 eV • Å = 1240 eV • nm = 1240 MeV • fm
- ℏc = 1973 eV • Å = 197.3 eV • nm = 197.3 MeV • fm
- kee2 = 14.40 eV • Å = 1.440 eV • nm = 1.440 MeV • fm
- kBT = 0.02585 eV at T = 300 K
Contributors and Attributions
Samuel J. Ling (Truman State University), Jeff Sanny (Loyola Marymount University), and Bill Moebs with many contributing authors. This work is licensed by OpenStax University Physics under a Creative Commons Attribution License (by 4.0).