2014 Fundamental Physical Constants --- Complete Listing From: http://physics.nist.gov/constants Quantity Value Uncertainty Unit ----------------------------------------------------------------------------------------------------------------------------- {220} lattice spacing of silicon 192.015 5714 e-12 0.000 0032 e-12 m alpha particle-electron mass ratio 7294.299 541 36 0.000 000 24 alpha particle mass 6.644 657 230 e-27 0.000 000 082 e-27 kg alpha particle mass energy equivalent 5.971 920 097 e-10 0.000 000 073 e-10 J alpha particle mass energy equivalent in MeV 3727.379 378 0.000 023 MeV alpha particle mass in u 4.001 506 179 127 0.000 000 000 063 u alpha particle molar mass 4.001 506 179 127 e-3 0.000 000 000 063 e-3 kg mol^-1 alpha particle-proton mass ratio 3.972 599 689 07 0.000 000 000 36 Angstrom star 1.000 014 95 e-10 0.000 000 90 e-10 m atomic mass constant 1.660 539 040 e-27 0.000 000 020 e-27 kg atomic mass constant energy equivalent 1.492 418 062 e-10 0.000 000 018 e-10 J atomic mass constant energy equivalent in MeV 931.494 0954 0.000 0057 MeV atomic mass unit-electron volt relationship 931.494 0954 e6 0.000 0057 e6 eV atomic mass unit-hartree relationship 3.423 177 6902 e7 0.000 000 0016 e7 E_h atomic mass unit-hertz relationship 2.252 342 7206 e23 0.000 000 0010 e23 Hz atomic mass unit-inverse meter relationship 7.513 006 6166 e14 0.000 000 0034 e14 m^-1 atomic mass unit-joule relationship 1.492 418 062 e-10 0.000 000 018 e-10 J atomic mass unit-kelvin relationship 1.080 954 38 e13 0.000 000 62 e13 K atomic mass unit-kilogram relationship 1.660 539 040 e-27 0.000 000 020 e-27 kg atomic unit of 1st hyperpolarizability 3.206 361 329 e-53 0.000 000 020 e-53 C^3 m^3 J^-2 atomic unit of 2nd hyperpolarizability 6.235 380 085 e-65 0.000 000 077 e-65 C^4 m^4 J^-3 atomic unit of action 1.054 571 800 e-34 0.000 000 013 e-34 J s atomic unit of charge 1.602 176 6208 e-19 0.000 000 0098 e-19 C atomic unit of charge density 1.081 202 3770 e12 0.000 000 0067 e12 C m^-3 atomic unit of current 6.623 618 183 e-3 0.000 000 041 e-3 A atomic unit of electric dipole mom. 8.478 353 552 e-30 0.000 000 052 e-30 C m atomic unit of electric field 5.142 206 707 e11 0.000 000 032 e11 V m^-1 atomic unit of electric field gradient 9.717 362 356 e21 0.000 000 060 e21 V m^-2 atomic unit of electric polarizability 1.648 777 2731 e-41 0.000 000 0011 e-41 C^2 m^2 J^-1 atomic unit of electric potential 27.211 386 02 0.000 000 17 V atomic unit of electric quadrupole mom. 4.486 551 484 e-40 0.000 000 028 e-40 C m^2 atomic unit of energy 4.359 744 650 e-18 0.000 000 054 e-18 J atomic unit of force 8.238 723 36 e-8 0.000 000 10 e-8 N atomic unit of length 0.529 177 210 67 e-10 0.000 000 000 12 e-10 m atomic unit of mag. dipole mom. 1.854 801 999 e-23 0.000 000 011 e-23 J T^-1 atomic unit of mag. flux density 2.350 517 550 e5 0.000 000 014 e5 T atomic unit of magnetizability 7.891 036 5886 e-29 0.000 000 0090 e-29 J T^-2 atomic unit of mass 9.109 383 56 e-31 0.000 000 11 e-31 kg atomic unit of mom.um 1.992 851 882 e-24 0.000 000 024 e-24 kg m s^-1 atomic unit of permittivity 1.112 650 056... e-10 (exact) F m^-1 atomic unit of time 2.418 884 326 509 e-17 0.000 000 000 014 e-17 s atomic unit of velocity 2.187 691 262 77 e6 0.000 000 000 50 e6 m s^-1 Avogadro constant 6.022 140 857 e23 0.000 000 074 e23 mol^-1 Bohr magneton 927.400 9994 e-26 0.000 0057 e-26 J T^-1 Bohr magneton in eV/T 5.788 381 8012 e-5 0.000 000 0026 e-5 eV T^-1 Bohr magneton in Hz/T 13.996 245 042 e9 0.000 000 086 e9 Hz T^-1 Bohr magneton in inverse meters per tesla 46.686 448 14 0.000 000 29 m^-1 T^-1 Bohr magneton in K/T 0.671 714 05 0.000 000 39 K T^-1 Bohr radius 0.529 177 210 67 e-10 0.000 000 000 12 e-10 m Boltzmann constant 1.380 648 52 e-23 0.000 000 79 e-23 J K^-1 Boltzmann constant in eV/K 8.617 3303 e-5 0.000 0050 e-5 eV K^-1 Boltzmann constant in Hz/K 2.083 6612 e10 0.000 0012 e10 Hz K^-1 Boltzmann constant in inverse meters per kelvin 69.503 457 0.000 040 m^-1 K^-1 characteristic impedance of vacuum 376.730 313 461... (exact) ohm classical electron radius 2.817 940 3227 e-15 0.000 000 0019 e-15 m Compton wavelength 2.426 310 2367 e-12 0.000 000 0011 e-12 m Compton wavelength over 2 pi 386.159 267 64 e-15 0.000 000 18 e-15 m conductance quantum 7.748 091 7310 e-5 0.000 000 0018 e-5 S conventional value of Josephson constant 483 597.9 e9 (exact) Hz V^-1 conventional value of von Klitzing constant 25 812.807 (exact) ohm Cu x unit 1.002 076 97 e-13 0.000 000 28 e-13 m deuteron-electron mag. mom. ratio -4.664 345 535 e-4 0.000 000 026 e-4 deuteron-electron mass ratio 3670.482 967 85 0.000 000 13 deuteron g factor 0.857 438 2311 0.000 000 0048 deuteron mag. mom. 0.433 073 5040 e-26 0.000 000 0036 e-26 J T^-1 deuteron mag. mom. to Bohr magneton ratio 0.466 975 4554 e-3 0.000 000 0026 e-3 deuteron mag. mom. to nuclear magneton ratio 0.857 438 2311 0.000 000 0048 deuteron mass 3.343 583 719 e-27 0.000 000 041 e-27 kg deuteron mass energy equivalent 3.005 063 183 e-10 0.000 000 037 e-10 J deuteron mass energy equivalent in MeV 1875.612 928 0.000 012 MeV deuteron mass in u 2.013 553 212 745 0.000 000 000 040 u deuteron molar mass 2.013 553 212 745 e-3 0.000 000 000 040 e-3 kg mol^-1 deuteron-neutron mag. mom. ratio -0.448 206 52 0.000 000 11 deuteron-proton mag. mom. ratio 0.307 012 2077 0.000 000 0015 deuteron-proton mass ratio 1.999 007 500 87 0.000 000 000 19 deuteron rms charge radius 2.1413 e-15 0.0025 e-15 m electric constant 8.854 187 817... e-12 (exact) F m^-1 electron charge to mass quotient -1.758 820 024 e11 0.000 000 011 e11 C kg^-1 electron-deuteron mag. mom. ratio -2143.923 499 0.000 012 electron-deuteron mass ratio 2.724 437 107 484 e-4 0.000 000 000 096 e-4 electron g factor -2.002 319 304 361 82 0.000 000 000 000 52 electron gyromag. ratio 1.760 859 644 e11 0.000 000 011 e11 s^-1 T^-1 electron gyromag. ratio over 2 pi 28 024.951 64 0.000 17 MHz T^-1 electron-helion mass ratio 1.819 543 074 854 e-4 0.000 000 000 088 e-4 electron mag. mom. -928.476 4620 e-26 0.000 0057 e-26 J T^-1 electron mag. mom. anomaly 1.159 652 180 91 e-3 0.000 000 000 26 e-3 electron mag. mom. to Bohr magneton ratio -1.001 159 652 180 91 0.000 000 000 000 26 electron mag. mom. to nuclear magneton ratio -1838.281 972 34 0.000 000 17 electron mass 9.109 383 56 e-31 0.000 000 11 e-31 kg electron mass energy equivalent 8.187 105 65 e-14 0.000 000 10 e-14 J electron mass energy equivalent in MeV 0.510 998 9461 0.000 000 0031 MeV electron mass in u 5.485 799 090 70 e-4 0.000 000 000 16 e-4 u electron molar mass 5.485 799 090 70 e-7 0.000 000 000 16 e-7 kg mol^-1 electron-muon mag. mom. ratio 206.766 9880 0.000 0046 electron-muon mass ratio 4.836 331 70 e-3 0.000 000 11 e-3 electron-neutron mag. mom. ratio 960.920 50 0.000 23 electron-neutron mass ratio 5.438 673 4428 e-4 0.000 000 0027 e-4 electron-proton mag. mom. ratio -658.210 6866 0.000 0020 electron-proton mass ratio 5.446 170 213 52 e-4 0.000 000 000 52 e-4 electron-tau mass ratio 2.875 92 e-4 0.000 26 e-4 electron to alpha particle mass ratio 1.370 933 554 798 e-4 0.000 000 000 045 e-4 electron to shielded helion mag. mom. ratio 864.058 257 0.000 010 electron to shielded proton mag. mom. ratio -658.227 5971 0.000 0072 electron-triton mass ratio 1.819 200 062 203 e-4 0.000 000 000 084 e-4 electron volt 1.602 176 6208 e-19 0.000 000 0098 e-19 J electron volt-atomic mass unit relationship 1.073 544 1105 e-9 0.000 000 0066 e-9 u electron volt-hartree relationship 3.674 932 248 e-2 0.000 000 023 e-2 E_h electron volt-hertz relationship 2.417 989 262 e14 0.000 000 015 e14 Hz electron volt-inverse meter relationship 8.065 544 005 e5 0.000 000 050 e5 m^-1 electron volt-joule relationship 1.602 176 6208 e-19 0.000 000 0098 e-19 J electron volt-kelvin relationship 1.160 452 21 e4 0.000 000 67 e4 K electron volt-kilogram relationship 1.782 661 907 e-36 0.000 000 011 e-36 kg elementary charge 1.602 176 6208 e-19 0.000 000 0098 e-19 C elementary charge over h 2.417 989 262 e14 0.000 000 015 e14 A J^-1 Faraday constant 96 485.332 89 0.000 59 C mol^-1 Faraday constant for conventional electric current 96 485.3251 0.0012 C_90 mol^-1 Fermi coupling constant 1.166 3787 e-5 0.000 0006 e-5 GeV^-2 fine-structure constant 7.297 352 5664 e-3 0.000 000 0017 e-3 first radiation constant 3.741 771 790 e-16 0.000 000 046 e-16 W m^2 first radiation constant for spectral radiance 1.191 042 953 e-16 0.000 000 015 e-16 W m^2 sr^-1 hartree-atomic mass unit relationship 2.921 262 3197 e-8 0.000 000 0013 e-8 u hartree-electron volt relationship 27.211 386 02 0.000 000 17 eV Hartree energy 4.359 744 650 e-18 0.000 000 054 e-18 J Hartree energy in eV 27.211 386 02 0.000 000 17 eV hartree-hertz relationship 6.579 683 920 711 e15 0.000 000 000 039 e15 Hz hartree-inverse meter relationship 2.194 746 313 702 e7 0.000 000 000 013 e7 m^-1 hartree-joule relationship 4.359 744 650 e-18 0.000 000 054 e-18 J hartree-kelvin relationship 3.157 7513 e5 0.000 0018 e5 K hartree-kilogram relationship 4.850 870 129 e-35 0.000 000 060 e-35 kg helion-electron mass ratio 5495.885 279 22 0.000 000 27 helion g factor -4.255 250 616 0.000 000 050 helion mag. mom. -1.074 617 522 e-26 0.000 000 014 e-26 J T^-1 helion mag. mom. to Bohr magneton ratio -1.158 740 958 e-3 0.000 000 014 e-3 helion mag. mom. to nuclear magneton ratio -2.127 625 308 0.000 000 025 helion mass 5.006 412 700 e-27 0.000 000 062 e-27 kg helion mass energy equivalent 4.499 539 341 e-10 0.000 000 055 e-10 J helion mass energy equivalent in MeV 2808.391 586 0.000 017 MeV helion mass in u 3.014 932 246 73 0.000 000 000 12 u helion molar mass 3.014 932 246 73 e-3 0.000 000 000 12 e-3 kg mol^-1 helion-proton mass ratio 2.993 152 670 46 0.000 000 000 29 hertz-atomic mass unit relationship 4.439 821 6616 e-24 0.000 000 0020 e-24 u hertz-electron volt relationship 4.135 667 662 e-15 0.000 000 025 e-15 eV hertz-hartree relationship 1.519 829 846 0088 e-16 0.000 000 000 0090 e-16 E_h hertz-inverse meter relationship 3.335 640 951... e-9 (exact) m^-1 hertz-joule relationship 6.626 070 040 e-34 0.000 000 081 e-34 J hertz-kelvin relationship 4.799 2447 e-11 0.000 0028 e-11 K hertz-kilogram relationship 7.372 497 201 e-51 0.000 000 091 e-51 kg inverse fine-structure constant 137.035 999 139 0.000 000 031 inverse meter-atomic mass unit relationship 1.331 025 049 00 e-15 0.000 000 000 61 e-15 u inverse meter-electron volt relationship 1.239 841 9739 e-6 0.000 000 0076 e-6 eV inverse meter-hartree relationship 4.556 335 252 767 e-8 0.000 000 000 027 e-8 E_h inverse meter-hertz relationship 299 792 458 (exact) Hz inverse meter-joule relationship 1.986 445 824 e-25 0.000 000 024 e-25 J inverse meter-kelvin relationship 1.438 777 36 e-2 0.000 000 83 e-2 K inverse meter-kilogram relationship 2.210 219 057 e-42 0.000 000 027 e-42 kg inverse of conductance quantum 12 906.403 7278 0.000 0029 ohm Josephson constant 483 597.8525 e9 0.0030 e9 Hz V^-1 joule-atomic mass unit relationship 6.700 535 363 e9 0.000 000 082 e9 u joule-electron volt relationship 6.241 509 126 e18 0.000 000 038 e18 eV joule-hartree relationship 2.293 712 317 e17 0.000 000 028 e17 E_h joule-hertz relationship 1.509 190 205 e33 0.000 000 019 e33 Hz joule-inverse meter relationship 5.034 116 651 e24 0.000 000 062 e24 m^-1 joule-kelvin relationship 7.242 9731 e22 0.000 0042 e22 K joule-kilogram relationship 1.112 650 056... e-17 (exact) kg kelvin-atomic mass unit relationship 9.251 0842 e-14 0.000 0053 e-14 u kelvin-electron volt relationship 8.617 3303 e-5 0.000 0050 e-5 eV kelvin-hartree relationship 3.166 8105 e-6 0.000 0018 e-6 E_h kelvin-hertz relationship 2.083 6612 e10 0.000 0012 e10 Hz kelvin-inverse meter relationship 69.503 457 0.000 040 m^-1 kelvin-joule relationship 1.380 648 52 e-23 0.000 000 79 e-23 J kelvin-kilogram relationship 1.536 178 65 e-40 0.000 000 88 e-40 kg kilogram-atomic mass unit relationship 6.022 140 857 e26 0.000 000 074 e26 u kilogram-electron volt relationship 5.609 588 650 e35 0.000 000 034 e35 eV kilogram-hartree relationship 2.061 485 823 e34 0.000 000 025 e34 E_h kilogram-hertz relationship 1.356 392 512 e50 0.000 000 017 e50 Hz kilogram-inverse meter relationship 4.524 438 411 e41 0.000 000 056 e41 m^-1 kilogram-joule relationship 8.987 551 787... e16 (exact) J kilogram-kelvin relationship 6.509 6595 e39 0.000 0037 e39 K lattice parameter of silicon 543.102 0504 e-12 0.000 0089 e-12 m Loschmidt constant (273.15 K, 100 kPa) 2.651 6467 e25 0.000 0015 e25 m^-3 Loschmidt constant (273.15 K, 101.325 kPa) 2.686 7811 e25 0.000 0015 e25 m^-3 mag. constant 12.566 370 614... e-7 (exact) N A^-2 mag. flux quantum 2.067 833 831 e-15 0.000 000 013 e-15 Wb molar gas constant 8.314 4598 0.000 0048 J mol^-1 K^-1 molar mass constant 1 e-3 (exact) kg mol^-1 molar mass of carbon-12 12 e-3 (exact) kg mol^-1 molar Planck constant 3.990 312 7110 e-10 0.000 000 0018 e-10 J s mol^-1 molar Planck constant times c 0.119 626 565 582 0.000 000 000 054 J m mol^-1 molar volume of ideal gas (273.15 K, 100 kPa) 22.710 947 e-3 0.000 013 e-3 m^3 mol^-1 molar volume of ideal gas (273.15 K, 101.325 kPa) 22.413 962 e-3 0.000 013 e-3 m^3 mol^-1 molar volume of silicon 12.058 832 14 e-6 0.000 000 61 e-6 m^3 mol^-1 Mo x unit 1.002 099 52 e-13 0.000 000 53 e-13 m muon Compton wavelength 11.734 441 11 e-15 0.000 000 26 e-15 m muon Compton wavelength over 2 pi 1.867 594 308 e-15 0.000 000 042 e-15 m muon-electron mass ratio 206.768 2826 0.000 0046 muon g factor -2.002 331 8418 0.000 000 0013 muon mag. mom. -4.490 448 26 e-26 0.000 000 10 e-26 J T^-1 muon mag. mom. anomaly 1.165 920 89 e-3 0.000 000 63 e-3 muon mag. mom. to Bohr magneton ratio -4.841 970 48 e-3 0.000 000 11 e-3 muon mag. mom. to nuclear magneton ratio -8.890 597 05 0.000 000 20 muon mass 1.883 531 594 e-28 0.000 000 048 e-28 kg muon mass energy equivalent 1.692 833 774 e-11 0.000 000 043 e-11 J muon mass energy equivalent in MeV 105.658 3745 0.000 0024 MeV muon mass in u 0.113 428 9257 0.000 000 0025 u muon molar mass 0.113 428 9257 e-3 0.000 000 0025 e-3 kg mol^-1 muon-neutron mass ratio 0.112 454 5167 0.000 000 0025 muon-proton mag. mom. ratio -3.183 345 142 0.000 000 071 muon-proton mass ratio 0.112 609 5262 0.000 000 0025 muon-tau mass ratio 5.946 49 e-2 0.000 54 e-2 natural unit of action 1.054 571 800 e-34 0.000 000 013 e-34 J s natural unit of action in eV s 6.582 119 514 e-16 0.000 000 040 e-16 eV s natural unit of energy 8.187 105 65 e-14 0.000 000 10 e-14 J natural unit of energy in MeV 0.510 998 9461 0.000 000 0031 MeV natural unit of length 386.159 267 64 e-15 0.000 000 18 e-15 m natural unit of mass 9.109 383 56 e-31 0.000 000 11 e-31 kg natural unit of mom.um 2.730 924 488 e-22 0.000 000 034 e-22 kg m s^-1 natural unit of mom.um in MeV/c 0.510 998 9461 0.000 000 0031 MeV/c natural unit of time 1.288 088 667 12 e-21 0.000 000 000 58 e-21 s natural unit of velocity 299 792 458 (exact) m s^-1 neutron Compton wavelength 1.319 590 904 81 e-15 0.000 000 000 88 e-15 m neutron Compton wavelength over 2 pi 0.210 019 415 36 e-15 0.000 000 000 14 e-15 m neutron-electron mag. mom. ratio 1.040 668 82 e-3 0.000 000 25 e-3 neutron-electron mass ratio 1838.683 661 58 0.000 000 90 neutron g factor -3.826 085 45 0.000 000 90 neutron gyromag. ratio 1.832 471 72 e8 0.000 000 43 e8 s^-1 T^-1 neutron gyromag. ratio over 2 pi 29.164 6933 0.000 0069 MHz T^-1 neutron mag. mom. -0.966 236 50 e-26 0.000 000 23 e-26 J T^-1 neutron mag. mom. to Bohr magneton ratio -1.041 875 63 e-3 0.000 000 25 e-3 neutron mag. mom. to nuclear magneton ratio -1.913 042 73 0.000 000 45 neutron mass 1.674 927 471 e-27 0.000 000 021 e-27 kg neutron mass energy equivalent 1.505 349 739 e-10 0.000 000 019 e-10 J neutron mass energy equivalent in MeV 939.565 4133 0.000 0058 MeV neutron mass in u 1.008 664 915 88 0.000 000 000 49 u neutron molar mass 1.008 664 915 88 e-3 0.000 000 000 49 e-3 kg mol^-1 neutron-muon mass ratio 8.892 484 08 0.000 000 20 neutron-proton mag. mom. ratio -0.684 979 34 0.000 000 16 neutron-proton mass difference 2.305 573 77 e-30 0.000 000 85 e-30 neutron-proton mass difference energy equivalent 2.072 146 37 e-13 0.000 000 76 e-13 neutron-proton mass difference energy equivalent in MeV 1.293 332 05 0.000 000 48 neutron-proton mass difference in u 0.001 388 449 00 0.000 000 000 51 neutron-proton mass ratio 1.001 378 418 98 0.000 000 000 51 neutron-tau mass ratio 0.528 790 0.000 048 neutron to shielded proton mag. mom. ratio -0.684 996 94 0.000 000 16 Newtonian constant of gravitation 6.674 08 e-11 0.000 31 e-11 m^3 kg^-1 s^-2 Newtonian constant of gravitation over h-bar c 6.708 61 e-39 0.000 31 e-39 (GeV/c^2)^-2 nuclear magneton 5.050 783 699 e-27 0.000 000 031 e-27 J T^-1 nuclear magneton in eV/T 3.152 451 2550 e-8 0.000 000 0015 e-8 eV T^-1 nuclear magneton in inverse meters per tesla 2.542 623 432 e-2 0.000 000 016 e-2 m^-1 T^-1 nuclear magneton in K/T 3.658 2690 e-4 0.000 0021 e-4 K T^-1 nuclear magneton in MHz/T 7.622 593 285 0.000 000 047 MHz T^-1 Planck constant 6.626 070 040 e-34 0.000 000 081 e-34 J s Planck constant in eV s 4.135 667 662 e-15 0.000 000 025 e-15 eV s Planck constant over 2 pi 1.054 571 800 e-34 0.000 000 013 e-34 J s Planck constant over 2 pi in eV s 6.582 119 514 e-16 0.000 000 040 e-16 eV s Planck constant over 2 pi times c in MeV fm 197.326 9788 0.000 0012 MeV fm Planck length 1.616 229 e-35 0.000 038 e-35 m Planck mass 2.176 470 e-8 0.000 051 e-8 kg Planck mass energy equivalent in GeV 1.220 910 e19 0.000 029 e19 GeV Planck temperature 1.416 808 e32 0.000 033 e32 K Planck time 5.391 16 e-44 0.000 13 e-44 s proton charge to mass quotient 9.578 833 226 e7 0.000 000 059 e7 C kg^-1 proton Compton wavelength 1.321 409 853 96 e-15 0.000 000 000 61 e-15 m proton Compton wavelength over 2 pi 0.210 308 910 109 e-15 0.000 000 000 097 e-15 m proton-electron mass ratio 1836.152 673 89 0.000 000 17 proton g factor 5.585 694 702 0.000 000 017 proton gyromag. ratio 2.675 221 900 e8 0.000 000 018 e8 s^-1 T^-1 proton gyromag. ratio over 2 pi 42.577 478 92 0.000 000 29 MHz T^-1 proton mag. mom. 1.410 606 7873 e-26 0.000 000 0097 e-26 J T^-1 proton mag. mom. to Bohr magneton ratio 1.521 032 2053 e-3 0.000 000 0046 e-3 proton mag. mom. to nuclear magneton ratio 2.792 847 3508 0.000 000 0085 proton mag. shielding correction 25.691 e-6 0.011 e-6 proton mass 1.672 621 898 e-27 0.000 000 021 e-27 kg proton mass energy equivalent 1.503 277 593 e-10 0.000 000 018 e-10 J proton mass energy equivalent in MeV 938.272 0813 0.000 0058 MeV proton mass in u 1.007 276 466 879 0.000 000 000 091 u proton molar mass 1.007 276 466 879 e-3 0.000 000 000 091 e-3 kg mol^-1 proton-muon mass ratio 8.880 243 38 0.000 000 20 proton-neutron mag. mom. ratio -1.459 898 05 0.000 000 34 proton-neutron mass ratio 0.998 623 478 44 0.000 000 000 51 proton rms charge radius 0.8751 e-15 0.0061 e-15 m proton-tau mass ratio 0.528 063 0.000 048 quantum of circulation 3.636 947 5486 e-4 0.000 000 0017 e-4 m^2 s^-1 quantum of circulation times 2 7.273 895 0972 e-4 0.000 000 0033 e-4 m^2 s^-1 Rydberg constant 10 973 731.568 508 0.000 065 m^-1 Rydberg constant times c in Hz 3.289 841 960 355 e15 0.000 000 000 019 e15 Hz Rydberg constant times hc in eV 13.605 693 009 0.000 000 084 eV Rydberg constant times hc in J 2.179 872 325 e-18 0.000 000 027 e-18 J Sackur-Tetrode constant (1 K, 100 kPa) -1.151 7084 0.000 0014 Sackur-Tetrode constant (1 K, 101.325 kPa) -1.164 8714 0.000 0014 second radiation constant 1.438 777 36 e-2 0.000 000 83 e-2 m K shielded helion gyromag. ratio 2.037 894 585 e8 0.000 000 027 e8 s^-1 T^-1 shielded helion gyromag. ratio over 2 pi 32.434 099 66 0.000 000 43 MHz T^-1 shielded helion mag. mom. -1.074 553 080 e-26 0.000 000 014 e-26 J T^-1 shielded helion mag. mom. to Bohr magneton ratio -1.158 671 471 e-3 0.000 000 014 e-3 shielded helion mag. mom. to nuclear magneton ratio -2.127 497 720 0.000 000 025 shielded helion to proton mag. mom. ratio -0.761 766 5603 0.000 000 0092 shielded helion to shielded proton mag. mom. ratio -0.761 786 1313 0.000 000 0033 shielded proton gyromag. ratio 2.675 153 171 e8 0.000 000 033 e8 s^-1 T^-1 shielded proton gyromag. ratio over 2 pi 42.576 385 07 0.000 000 53 MHz T^-1 shielded proton mag. mom. 1.410 570 547 e-26 0.000 000 018 e-26 J T^-1 shielded proton mag. mom. to Bohr magneton ratio 1.520 993 128 e-3 0.000 000 017 e-3 shielded proton mag. mom. to nuclear magneton ratio 2.792 775 600 0.000 000 030 speed of light in vacuum 299 792 458 (exact) m s^-1 standard acceleration of gravity 9.806 65 (exact) m s^-2 standard atmosphere 101 325 (exact) Pa standard-state pressure 100 000 (exact) Pa Stefan-Boltzmann constant 5.670 367 e-8 0.000 013 e-8 W m^-2 K^-4 tau Compton wavelength 0.697 787 e-15 0.000 063 e-15 m tau Compton wavelength over 2 pi 0.111 056 e-15 0.000 010 e-15 m tau-electron mass ratio 3477.15 0.31 tau mass 3.167 47 e-27 0.000 29 e-27 kg tau mass energy equivalent 2.846 78 e-10 0.000 26 e-10 J tau mass energy equivalent in MeV 1776.82 0.16 MeV tau mass in u 1.907 49 0.000 17 u tau molar mass 1.907 49 e-3 0.000 17 e-3 kg mol^-1 tau-muon mass ratio 16.8167 0.0015 tau-neutron mass ratio 1.891 11 0.000 17 tau-proton mass ratio 1.893 72 0.000 17 Thomson cross section 0.665 245 871 58 e-28 0.000 000 000 91 e-28 m^2 triton-electron mass ratio 5496.921 535 88 0.000 000 26 triton g factor 5.957 924 920 0.000 000 028 triton mag. mom. 1.504 609 503 e-26 0.000 000 012 e-26 J T^-1 triton mag. mom. to Bohr magneton ratio 1.622 393 6616 e-3 0.000 000 0076 e-3 triton mag. mom. to nuclear magneton ratio 2.978 962 460 0.000 000 014 triton mass 5.007 356 665 e-27 0.000 000 062 e-27 kg triton mass energy equivalent 4.500 387 735 e-10 0.000 000 055 e-10 J triton mass energy equivalent in MeV 2808.921 112 0.000 017 MeV triton mass in u 3.015 500 716 32 0.000 000 000 11 u triton molar mass 3.015 500 716 32 e-3 0.000 000 000 11 e-3 kg mol^-1 triton-proton mass ratio 2.993 717 033 48 0.000 000 000 22 unified atomic mass unit 1.660 539 040 e-27 0.000 000 020 e-27 kg von Klitzing constant 25 812.807 4555 0.000 0059 ohm weak mixing angle 0.2223 0.0021 Wien frequency displacement law constant 5.878 9238 e10 0.000 0034 e10 Hz K^-1 Wien wavelength displacement law constant 2.897 7729 e-3 0.000 0017 e-3 m K