| QUANTITY | SYMBOL(S) | VALUE(S) |
| Acceleration due to gravity | g | 9.807 m s-2 |
| Atomic mass unit | u | 1.660 x 10-27 kg |
| Avogadro constant | NA | 6.022 x 1023 mol-1 |
| Bohr magneton | μB | 9.274 x 10-24 J T-1 |
| Bohr radius | a0 | 5.292 x 10-11 m |
| Boltzmann constant | k kB |
1.380 x 10-23 J K-1 |
| Characteristic impedance of free space | Z0 | 120p Ω |
| Compton wavelength (e) | λCe | 2.426 x 10-12 m |
| Compton wavelength (n) | λCn | 1.320 x 10-15 m |
| Compton wavelength (p) | λCp | 1.321 x 10-15 m |
| Electron radius | τe | 2.818 x 10-15 m |
| Electron volt | eV | 1.602 x 10-19 J |
| Elementary charge | e | 1.602 x 10-19 C |
| Faraday constant | F | 9.648 x 104 C mol-1 |
| Fine structure constant | a | 7.297 x 10-3 |
| Gas constant | R | 8.314 J K-1 mol-1
1.987 cal oC-1 mol-1 8.206 x 10-2 dm3 atm K-1 mol-1 |
| Gravitational constant | G | 6.672 x 10-11 N m2 kg-2 |
| Intrinsic impedance | h | 3.767 x 102 Ω |
| Loschmidt constant | NL | 2.687 x 1025 m-3 |
| Mass of electron | me | 9.109 x 10-31 kg |
| Mass of neutron | mn | 1.675 x 10-27 kg |
| Mass of proton | mp | 1.673 x 10-27 kg |
| Nuclear magneton | μN | 5.051 x 10-27 J T-1 |
| Pi (to 12 sig.figs.) | π | 3.14159265359 |
| Planck constant | h | 6.626 x 10-34 J s |
| Rydberg constant | R∞ | 1.097 x 105 cm-1 |
| Speed of light | c | 2.998 x 108 m s-1 |
| Stefan-Boltzmann constant | σ | 5.67 x 10-8 W m-2 K-4
1.712 x 10-9 Btu hr-1 ft2 oR-4 |
| Vacuum permeability | μ0 | 4p x 10-7 J s2 C-2 m -1
4p x 10-7 T2 J-1 m 3 |
| Vacuum permittivity | ε0 | 8.854 x 10-12 J-1 C2 m -1 |