Physical Constants
| Quantity | Symbol | Value | Unit |
|---|---|---|---|
| Universal | |||
| Speed of light in vacuum | c | 299 792 458 | m·s−1 |
| Newtonian constant of gravitation | G | 6.674 30(15) × 10−11 | m3·kg−1·s−2 |
| Planck constant | h | 6.626 070 15 × 10−34 | J·Hz−1 |
| Reduced Planck constant | ħ | 1.054 571 817… × 10−34 | J·s |
| Standard acceleration of gravity | gn | 9.806 65 | m·s−2 |
| Standard atmosphere | atm | 101 325 | Pa |
| Standard-state pressure | p° | 100 000 | Pa |
| Electromagnetic | |||
| Vacuum permittivity | ε0 | 8.854 187 8188(14) × 10−12 | F·m−1 |
| Magnetic constant | μ0 | 1.256 637 061 27(20) × 10−6 | N·A−2 |
| Elementary charge | e | 1.602 176 634 × 10−19 | C |
| Magnetic flux quantum | Φ0 | 2.067 833 848… × 10−15 | Wb |
| Conductance quantum | G0 | 7.748 091 729… × 10−5 | S |
| Josephson constant | KJ | 483 597.848 4… × 109 | Hz·V−1 |
| von Klitzing constant | RK | 25 812.807 45… | Ω |
| Bohr magneton | μB | 9.274 010 0657(29) × 10−24 | J·T−1 |
| Nuclear magneton | μN | 5.050 783 7393(16) × 10−27 | J·T−1 |
| Atomic and nuclear | |||
| Fine-structure constant | α | 7.297 352 5643(11) × 10−3 | |
| Inverse fine-structure constant | α−1 | 137.035 999 177(21) | |
| Rydberg constant | R∞ | 10 973 731.568 157(12) | m−1 |
| Bohr radius | a0 | 5.291 772 105 44(82) × 10−11 | m |
| Hartree energy | Eh | 4.359 744 722 2060(48) × 10−18 | J |
| Electron mass | me | 9.109 383 7139(28) × 10−31 | kg |
| Electron mass energy equivalent | mec2 | 0.510 998 950 69(16) | MeV |
| Electron charge-to-mass quotient | −e/me | −1.758 820 008 38(55) × 1011 | C·kg−1 |
| Classical electron radius | re | 2.817 940 3205(13) × 10−15 | m |
| Compton wavelength | λC | 2.426 310 235 38(76) × 10−12 | m |
| Thomson cross section | σe | 6.652 458 7051(62) × 10−29 | m2 |
| Electron g-factor | ge | −2.002 319 304 360 92(36) | |
| Proton mass | mp | 1.672 621 925 95(52) × 10−27 | kg |
| Proton-electron mass ratio | mp/me | 1836.152 673 426(32) | |
| Neutron mass | mn | 1.674 927 500 56(85) × 10−27 | kg |
| Deuteron mass | md | 3.343 583 7768(10) × 10−27 | kg |
| Alpha particle mass | mα | 6.644 657 3450(21) × 10−27 | kg |
| Physico-chemical | |||
| Avogadro constant | NA | 6.022 140 76 × 1023 | mol−1 |
| Boltzmann constant | k | 1.380 649 × 10−23 | J·K−1 |
| Faraday constant | F | 96 485.332 12… | C·mol−1 |
| Molar gas constant | R | 8.314 462 618… | J·mol−1·K−1 |
| Atomic mass constant | mu | 1.660 539 068 92(52) × 10−27 | kg |
| Atomic mass constant energy equivalent | muc2 | 931.494 103 72(29) | MeV |
| Electron volt | eV | 1.602 176 634 × 10−19 | J |
| Molar mass constant | Mu | 1.000 000 001 05(31) × 10−3 | kg·mol−1 |
| Molar Planck constant | NAh | 3.990 312 712… × 10−10 | J·Hz−1·mol−1 |
| Molar volume of ideal gas (273.15 K, 101.325 kPa) | Vm | 22.413 969 54… × 10−3 | m3·mol−1 |
| Molar volume of ideal gas (273.15 K, 100 kPa) | Vm | 22.710 954 64… × 10−3 | m3·mol−1 |
| Loschmidt constant (273.15 K, 101.325 kPa) | n0 | 2.686 780 111… × 1025 | m−3 |
| Stefan-Boltzmann constant | σ | 5.670 374 419… × 10−8 | W·m−2·K−4 |
| First radiation constant | c1 | 3.741 771 852… × 10−16 | W·m2 |
| Second radiation constant | c2 | 1.438 776 877… × 10−2 | m·K |
| Wien wavelength displacement constant | b | 2.897 771 955… × 10−3 | m·K |
Universal
- Speed of light in vacuumc299 792 458m·s−1
- Newtonian constant of gravitationG6.674 30(15) × 10−11m3·kg−1·s−2
- Planck constanth6.626 070 15 × 10−34J·Hz−1
- Reduced Planck constantħ1.054 571 817… × 10−34J·s
- Standard acceleration of gravitygn9.806 65m·s−2
- Standard atmosphereatm101 325Pa
- Standard-state pressurep°100 000Pa
Electromagnetic
- Vacuum permittivityε08.854 187 8188(14) × 10−12F·m−1
- Magnetic constantμ01.256 637 061 27(20) × 10−6N·A−2
- Elementary chargee1.602 176 634 × 10−19C
- Magnetic flux quantumΦ02.067 833 848… × 10−15Wb
- Conductance quantumG07.748 091 729… × 10−5S
- Josephson constantKJ483 597.848 4… × 109Hz·V−1
- von Klitzing constantRK25 812.807 45…Ω
- Bohr magnetonμB9.274 010 0657(29) × 10−24J·T−1
- Nuclear magnetonμN5.050 783 7393(16) × 10−27J·T−1
Atomic and nuclear
- Fine-structure constantα7.297 352 5643(11) × 10−3
- Inverse fine-structure constantα−1137.035 999 177(21)
- Rydberg constantR∞10 973 731.568 157(12)m−1
- Bohr radiusa05.291 772 105 44(82) × 10−11m
- Hartree energyEh4.359 744 722 2060(48) × 10−18J
- Electron massme9.109 383 7139(28) × 10−31kg
- Electron mass energy equivalentmec20.510 998 950 69(16)MeV
- Electron charge-to-mass quotient−e/me−1.758 820 008 38(55) × 1011C·kg−1
- Classical electron radiusre2.817 940 3205(13) × 10−15m
- Compton wavelengthλC2.426 310 235 38(76) × 10−12m
- Thomson cross sectionσe6.652 458 7051(62) × 10−29m2
- Electron g-factorge−2.002 319 304 360 92(36)
- Proton massmp1.672 621 925 95(52) × 10−27kg
- Proton-electron mass ratiomp/me1836.152 673 426(32)
- Neutron massmn1.674 927 500 56(85) × 10−27kg
- Deuteron massmd3.343 583 7768(10) × 10−27kg
- Alpha particle massmα6.644 657 3450(21) × 10−27kg
Physico-chemical
- Avogadro constantNA6.022 140 76 × 1023mol−1
- Boltzmann constantk1.380 649 × 10−23J·K−1
- Faraday constantF96 485.332 12…C·mol−1
- Molar gas constantR8.314 462 618…J·mol−1·K−1
- Atomic mass constantmu1.660 539 068 92(52) × 10−27kg
- Atomic mass constant energy equivalentmuc2931.494 103 72(29)MeV
- Electron volteV1.602 176 634 × 10−19J
- Molar mass constantMu1.000 000 001 05(31) × 10−3kg·mol−1
- Molar Planck constantNAh3.990 312 712… × 10−10J·Hz−1·mol−1
- Molar volume of ideal gas (273.15 K, 101.325 kPa)Vm22.413 969 54… × 10−3m3·mol−1
- Molar volume of ideal gas (273.15 K, 100 kPa)Vm22.710 954 64… × 10−3m3·mol−1
- Loschmidt constant (273.15 K, 101.325 kPa)n02.686 780 111… × 1025m−3
- Stefan-Boltzmann constantσ5.670 374 419… × 10−8W·m−2·K−4
- First radiation constantc13.741 771 852… × 10−16W·m2
- Second radiation constantc21.438 776 877… × 10−2m·K
- Wien wavelength displacement constantb2.897 771 955… × 10−3m·K