2010 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 5361 0.000 0029 alpha particle mass 6.644 656 75 e-27 0.000 000 29 e-27 kg alpha particle mass energy equivalent 5.971 919 67 e-10 0.000 000 26 e-10 J alpha particle mass energy equivalent in MeV 3727.379 240 0.000 082 MeV alpha particle mass in u 4.001 506 179 125 0.000 000 000 062 u alpha particle molar mass 4.001 506 179 125 e-3 0.000 000 000 062 e-3 kg mol^-1 alpha particle-proton mass ratio 3.972 599 689 33 0.000 000 000 36 Angstrom star 1.000 014 95 e-10 0.000 000 90 e-10 m atomic mass constant 1.660 538 921 e-27 0.000 000 073 e-27 kg atomic mass constant energy equivalent 1.492 417 954 e-10 0.000 000 066 e-10 J atomic mass constant energy equivalent in MeV 931.494 061 0.000 021 MeV atomic mass unit-electron volt relationship 931.494 061 e6 0.000 021 e6 eV atomic mass unit-hartree relationship 3.423 177 6845 e7 0.000 000 0024 e7 E_h atomic mass unit-hertz relationship 2.252 342 7168 e23 0.000 000 0016 e23 Hz atomic mass unit-inverse meter relationship 7.513 006 6042 e14 0.000 000 0053 e14 m^-1 atomic mass unit-joule relationship 1.492 417 954 e-10 0.000 000 066 e-10 J atomic mass unit-kelvin relationship 1.080 954 08 e13 0.000 000 98 e13 K atomic mass unit-kilogram relationship 1.660 538 921 e-27 0.000 000 073 e-27 kg atomic unit of 1st hyperpolarizability 3.206 361 449 e-53 0.000 000 071 e-53 C^3 m^3 J^-2 atomic unit of 2nd hyperpolarizability 6.235 380 54 e-65 0.000 000 28 e-65 C^4 m^4 J^-3 atomic unit of action 1.054 571 726 e-34 0.000 000 047 e-34 J s atomic unit of charge 1.602 176 565 e-19 0.000 000 035 e-19 C atomic unit of charge density 1.081 202 338 e12 0.000 000 024 e12 C m^-3 atomic unit of current 6.623 617 95 e-3 0.000 000 15 e-3 A atomic unit of electric dipole mom. 8.478 353 26 e-30 0.000 000 19 e-30 C m atomic unit of electric field 5.142 206 52 e11 0.000 000 11 e11 V m^-1 atomic unit of electric field gradient 9.717 362 00 e21 0.000 000 21 e21 V m^-2 atomic unit of electric polarizability 1.648 777 2754 e-41 0.000 000 0016 e-41 C^2 m^2 J^-1 atomic unit of electric potential 27.211 385 05 0.000 000 60 V atomic unit of electric quadrupole mom. 4.486 551 331 e-40 0.000 000 099 e-40 C m^2 atomic unit of energy 4.359 744 34 e-18 0.000 000 19 e-18 J atomic unit of force 8.238 722 78 e-8 0.000 000 36 e-8 N atomic unit of length 0.529 177 210 92 e-10 0.000 000 000 17 e-10 m atomic unit of mag. dipole mom. 1.854 801 936 e-23 0.000 000 041 e-23 J T^-1 atomic unit of mag. flux density 2.350 517 464 e5 0.000 000 052 e5 T atomic unit of magnetizability 7.891 036 607 e-29 0.000 000 013 e-29 J T^-2 atomic unit of mass 9.109 382 91 e-31 0.000 000 40 e-31 kg atomic unit of mom.um 1.992 851 740 e-24 0.000 000 088 e-24 kg m s^-1 atomic unit of permittivity 1.112 650 056... e-10 (exact) F m^-1 atomic unit of time 2.418 884 326 502 e-17 0.000 000 000 012 e-17 s atomic unit of velocity 2.187 691 263 79 e6 0.000 000 000 71 e6 m s^-1 Avogadro constant 6.022 141 29 e23 0.000 000 27 e23 mol^-1 Bohr magneton 927.400 968 e-26 0.000 020 e-26 J T^-1 Bohr magneton in eV/T 5.788 381 8066 e-5 0.000 000 0038 e-5 eV T^-1 Bohr magneton in Hz/T 13.996 245 55 e9 0.000 000 31 e9 Hz T^-1 Bohr magneton in inverse meters per tesla 46.686 4498 0.000 0010 m^-1 T^-1 Bohr magneton in K/T 0.671 713 88 0.000 000 61 K T^-1 Bohr radius 0.529 177 210 92 e-10 0.000 000 000 17 e-10 m Boltzmann constant 1.380 6488 e-23 0.000 0013 e-23 J K^-1 Boltzmann constant in eV/K 8.617 3324 e-5 0.000 0078 e-5 eV K^-1 Boltzmann constant in Hz/K 2.083 6618 e10 0.000 0019 e10 Hz K^-1 Boltzmann constant in inverse meters per kelvin 69.503 476 0.000 063 m^-1 K^-1 characteristic impedance of vacuum 376.730 313 461... (exact) ohm classical electron radius 2.817 940 3267 e-15 0.000 000 0027 e-15 m Compton wavelength 2.426 310 2389 e-12 0.000 000 0016 e-12 m Compton wavelength over 2 pi 386.159 268 00 e-15 0.000 000 25 e-15 m conductance quantum 7.748 091 7346 e-5 0.000 000 0025 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 -4.664 345 537 e-4 0.000 000 039 e-4 deuteron-electron mass ratio 3670.482 9652 0.000 0015 deuteron g factor 0.857 438 2308 0.000 000 0072 deuteron mag. mom. 0.433 073 489 e-26 0.000 000 010 e-26 J T^-1 deuteron mag. mom. to Bohr magneton ratio 0.466 975 4556 e-3 0.000 000 0039 e-3 deuteron mag. mom. to nuclear magneton ratio 0.857 438 2308 0.000 000 0072 deuteron mass 3.343 583 48 e-27 0.000 000 15 e-27 kg deuteron mass energy equivalent 3.005 062 97 e-10 0.000 000 13 e-10 J deuteron mass energy equivalent in MeV 1875.612 859 0.000 041 MeV deuteron mass in u 2.013 553 212 712 0.000 000 000 077 u deuteron molar mass 2.013 553 212 712 e-3 0.000 000 000 077 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 2070 0.000 000 0024 deuteron-proton mass ratio 1.999 007 500 97 0.000 000 000 18 deuteron rms charge radius 2.1424 e-15 0.0021 e-15 m electric constant 8.854 187 817... e-12 (exact) F m^-1 electron charge to mass quotient -1.758 820 088 e11 0.000 000 039 e11 C kg^-1 electron-deuteron mag. mom. ratio -2143.923 498 0.000 018 electron-deuteron mass ratio 2.724 437 1095 e-4 0.000 000 0011 e-4 electron g factor -2.002 319 304 361 53 0.000 000 000 000 53 electron gyromag. ratio 1.760 859 708 e11 0.000 000 039 e11 s^-1 T^-1 electron gyromag. ratio over 2 pi 28 024.952 66 0.000 62 MHz T^-1 electron-helion mass ratio 1.819 543 0761 e-4 0.000 000 0017 e-4 electron mag. mom. -928.476 430 e-26 0.000 021 e-26 J T^-1 electron mag. mom. anomaly 1.159 652 180 76 e-3 0.000 000 000 27 e-3 electron mag. mom. to Bohr magneton ratio -1.001 159 652 180 76 0.000 000 000 000 27 electron mag. mom. to nuclear magneton ratio -1838.281 970 90 0.000 000 75 electron mass 9.109 382 91 e-31 0.000 000 40 e-31 kg electron mass energy equivalent 8.187 105 06 e-14 0.000 000 36 e-14 J electron mass energy equivalent in MeV 0.510 998 928 0.000 000 011 MeV electron mass in u 5.485 799 0946 e-4 0.000 000 0022 e-4 u electron molar mass 5.485 799 0946 e-7 0.000 000 0022 e-7 kg mol^-1 electron-muon mag. mom. ratio 206.766 9896 0.000 0052 electron-muon mass ratio 4.836 331 66 e-3 0.000 000 12 e-3 electron-neutron mag. mom. ratio 960.920 50 0.000 23 electron-neutron mass ratio 5.438 673 4461 e-4 0.000 000 0032 e-4 electron-proton mag. mom. ratio -658.210 6848 0.000 0054 electron-proton mass ratio 5.446 170 2178 e-4 0.000 000 0022 e-4 electron-tau mass ratio 2.875 92 e-4 0.000 26 e-4 electron to alpha particle mass ratio 1.370 933 555 78 e-4 0.000 000 000 55 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 0653 e-4 0.000 000 0017 e-4 electron volt 1.602 176 565 e-19 0.000 000 035 e-19 J electron volt-atomic mass unit relationship 1.073 544 150 e-9 0.000 000 024 e-9 u electron volt-hartree relationship 3.674 932 379 e-2 0.000 000 081 e-2 E_h electron volt-hertz relationship 2.417 989 348 e14 0.000 000 053 e14 Hz electron volt-inverse meter relationship 8.065 544 29 e5 0.000 000 18 e5 m^-1 electron volt-joule relationship 1.602 176 565 e-19 0.000 000 035 e-19 J electron volt-kelvin relationship 1.160 4519 e4 0.000 0011 e4 K electron volt-kilogram relationship 1.782 661 845 e-36 0.000 000 039 e-36 kg elementary charge 1.602 176 565 e-19 0.000 000 035 e-19 C elementary charge over h 2.417 989 348 e14 0.000 000 053 e14 A J^-1 Faraday constant 96 485.3365 0.0021 C mol^-1 Faraday constant for conventional electric current 96 485.3321 0.0043 C_90 mol^-1 Fermi coupling constant 1.166 364 e-5 0.000 005 e-5 GeV^-2 fine-structure constant 7.297 352 5698 e-3 0.000 000 0024 e-3 first radiation constant 3.741 771 53 e-16 0.000 000 17 e-16 W m^2 first radiation constant for spectral radiance 1.191 042 869 e-16 0.000 000 053 e-16 W m^2 sr^-1 hartree-atomic mass unit relationship 2.921 262 3246 e-8 0.000 000 0021 e-8 u hartree-electron volt relationship 27.211 385 05 0.000 000 60 eV Hartree energy 4.359 744 34 e-18 0.000 000 19 e-18 J Hartree energy in eV 27.211 385 05 0.000 000 60 eV hartree-hertz relationship 6.579 683 920 729 e15 0.000 000 000 033 e15 Hz hartree-inverse meter relationship 2.194 746 313 708 e7 0.000 000 000 011 e7 m^-1 hartree-joule relationship 4.359 744 34 e-18 0.000 000 19 e-18 J hartree-kelvin relationship 3.157 7504 e5 0.000 0029 e5 K hartree-kilogram relationship 4.850 869 79 e-35 0.000 000 21 e-35 kg helion-electron mass ratio 5495.885 2754 0.000 0050 helion g factor -4.255 250 613 0.000 000 050 helion mag. mom. -1.074 617 486 e-26 0.000 000 027 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 -2.127 625 306 0.000 000 025 helion mass 5.006 412 34 e-27 0.000 000 22 e-27 kg helion mass energy equivalent 4.499 539 02 e-10 0.000 000 20 e-10 J helion mass energy equivalent in MeV 2808.391 482 0.000 062 MeV helion mass in u 3.014 932 2468 0.000 000 0025 u helion molar mass 3.014 932 2468 e-3 0.000 000 0025 e-3 kg mol^-1 helion-proton mass ratio 2.993 152 6707 0.000 000 0025 hertz-atomic mass unit relationship 4.439 821 6689 e-24 0.000 000 0031 e-24 u hertz-electron volt relationship 4.135 667 516 e-15 0.000 000 091 e-15 eV hertz-hartree relationship 1.519 829 846 0045 e-16 0.000 000 000 0076 e-16 E_h hertz-inverse meter relationship 3.335 640 951... e-9 (exact) m^-1 hertz-joule relationship 6.626 069 57 e-34 0.000 000 29 e-34 J hertz-kelvin relationship 4.799 2434 e-11 0.000 0044 e-11 K hertz-kilogram relationship 7.372 496 68 e-51 0.000 000 33 e-51 kg inverse fine-structure constant 137.035 999 074 0.000 000 044 inverse meter-atomic mass unit relationship 1.331 025 051 20 e-15 0.000 000 000 94 e-15 u inverse meter-electron volt relationship 1.239 841 930 e-6 0.000 000 027 e-6 eV inverse meter-hartree relationship 4.556 335 252 755 e-8 0.000 000 000 023 e-8 E_h inverse meter-hertz relationship 299 792 458 (exact) Hz inverse meter-joule relationship 1.986 445 684 e-25 0.000 000 088 e-25 J inverse meter-kelvin relationship 1.438 7770 e-2 0.000 0013 e-2 K inverse meter-kilogram relationship 2.210 218 902 e-42 0.000 000 098 e-42 kg inverse of conductance quantum 12 906.403 7217 0.000 0042 ohm Josephson constant 483 597.870 e9 0.011 e9 Hz V^-1 joule-atomic mass unit relationship 6.700 535 85 e9 0.000 000 30 e9 u joule-electron volt relationship 6.241 509 34 e18 0.000 000 14 e18 eV joule-hartree relationship 2.293 712 48 e17 0.000 000 10 e17 E_h joule-hertz relationship 1.509 190 311 e33 0.000 000 067 e33 Hz joule-inverse meter relationship 5.034 117 01 e24 0.000 000 22 e24 m^-1 joule-kelvin relationship 7.242 9716 e22 0.000 0066 e22 K joule-kilogram relationship 1.112 650 056... e-17 (exact) kg kelvin-atomic mass unit relationship 9.251 0868 e-14 0.000 0084 e-14 u kelvin-electron volt relationship 8.617 3324 e-5 0.000 0078 e-5 eV kelvin-hartree relationship 3.166 8114 e-6 0.000 0029 e-6 E_h kelvin-hertz relationship 2.083 6618 e10 0.000 0019 e10 Hz kelvin-inverse meter relationship 69.503 476 0.000 063 m^-1 kelvin-joule relationship 1.380 6488 e-23 0.000 0013 e-23 J kelvin-kilogram relationship 1.536 1790 e-40 0.000 0014 e-40 kg kilogram-atomic mass unit relationship 6.022 141 29 e26 0.000 000 27 e26 u kilogram-electron volt relationship 5.609 588 85 e35 0.000 000 12 e35 eV kilogram-hartree relationship 2.061 485 968 e34 0.000 000 091 e34 E_h kilogram-hertz relationship 1.356 392 608 e50 0.000 000 060 e50 Hz kilogram-inverse meter relationship 4.524 438 73 e41 0.000 000 20 e41 m^-1 kilogram-joule relationship 8.987 551 787... e16 (exact) J kilogram-kelvin relationship 6.509 6582 e39 0.000 0059 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 6462 e25 0.000 0024 e25 m^-3 Loschmidt constant (273.15 K, 101.325 kPa) 2.686 7805 e25 0.000 0024 e25 m^-3 mag. constant 12.566 370 614... e-7 (exact) N A^-2 mag. flux quantum 2.067 833 758 e-15 0.000 000 046 e-15 Wb molar gas constant 8.314 4621 0.000 0075 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 7176 e-10 0.000 000 0028 e-10 J s mol^-1 molar Planck constant times c 0.119 626 565 779 0.000 000 000 084 J m mol^-1 molar volume of ideal gas (273.15 K, 100 kPa) 22.710 953 e-3 0.000 021 e-3 m^3 mol^-1 molar volume of ideal gas (273.15 K, 101.325 kPa) 22.413 968 e-3 0.000 020 e-3 m^3 mol^-1 molar volume of silicon 12.058 833 01 e-6 0.000 000 80 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 03 e-15 0.000 000 30 e-15 m muon Compton wavelength over 2 pi 1.867 594 294 e-15 0.000 000 047 e-15 m muon-electron mass ratio 206.768 2843 0.000 0052 muon g factor -2.002 331 8418 0.000 000 0013 muon mag. mom. -4.490 448 07 e-26 0.000 000 15 e-26 J T^-1 muon mag. mom. anomaly 1.165 920 91 e-3 0.000 000 63 e-3 muon mag. mom. to Bohr magneton ratio -4.841 970 44 e-3 0.000 000 12 e-3 muon mag. mom. to nuclear magneton ratio -8.890 596 97 0.000 000 22 muon mass 1.883 531 475 e-28 0.000 000 096 e-28 kg muon mass energy equivalent 1.692 833 667 e-11 0.000 000 086 e-11 J muon mass energy equivalent in MeV 105.658 3715 0.000 0035 MeV muon mass in u 0.113 428 9267 0.000 000 0029 u muon molar mass 0.113 428 9267 e-3 0.000 000 0029 e-3 kg mol^-1 muon-neutron mass ratio 0.112 454 5177 0.000 000 0028 muon-proton mag. mom. ratio -3.183 345 107 0.000 000 084 muon-proton mass ratio 0.112 609 5272 0.000 000 0028 muon-tau mass ratio 5.946 49 e-2 0.000 54 e-2 natural unit of action 1.054 571 726 e-34 0.000 000 047 e-34 J s natural unit of action in eV s 6.582 119 28 e-16 0.000 000 15 e-16 eV s natural unit of energy 8.187 105 06 e-14 0.000 000 36 e-14 J natural unit of energy in MeV 0.510 998 928 0.000 000 011 MeV natural unit of length 386.159 268 00 e-15 0.000 000 25 e-15 m natural unit of mass 9.109 382 91 e-31 0.000 000 40 e-31 kg natural unit of mom.um 2.730 924 29 e-22 0.000 000 12 e-22 kg m s^-1 natural unit of mom.um in MeV/c 0.510 998 928 0.000 000 011 MeV/c natural unit of time 1.288 088 668 33 e-21 0.000 000 000 83 e-21 s natural unit of velocity 299 792 458 (exact) m s^-1 neutron Compton wavelength 1.319 590 9068 e-15 0.000 000 0011 e-15 m neutron Compton wavelength over 2 pi 0.210 019 415 68 e-15 0.000 000 000 17 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 6605 0.000 0011 neutron g factor -3.826 085 45 0.000 000 90 neutron gyromag. ratio 1.832 471 79 e8 0.000 000 43 e8 s^-1 T^-1 neutron gyromag. ratio over 2 pi 29.164 6943 0.000 0069 MHz T^-1 neutron mag. mom. -0.966 236 47 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 72 0.000 000 45 neutron mass 1.674 927 351 e-27 0.000 000 074 e-27 kg neutron mass energy equivalent 1.505 349 631 e-10 0.000 000 066 e-10 J neutron mass energy equivalent in MeV 939.565 379 0.000 021 MeV neutron mass in u 1.008 664 916 00 0.000 000 000 43 u neutron molar mass 1.008 664 916 00 e-3 0.000 000 000 43 e-3 kg mol^-1 neutron-muon mass ratio 8.892 484 00 0.000 000 22 neutron-proton mag. mom. ratio -0.684 979 34 0.000 000 16 neutron-proton mass difference 2.305 573 92 e-30 0.000 000 76 e-30 neutron-proton mass difference energy equivalent 2.072 146 50 e-13 0.000 000 68 e-13 neutron-proton mass difference energy equivalent in MeV 1.293 332 17 0.000 000 42 neutron-proton mass difference in u 0.001 388 449 19 0.000 000 000 45 neutron-proton mass ratio 1.001 378 419 17 0.000 000 000 45 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 6.673 84 e-11 0.000 80 e-11 m^3 kg^-1 s^-2 Newtonian constant of gravitation over h-bar c 6.708 37 e-39 0.000 80 e-39 (GeV/c^2)^-2 nuclear magneton 5.050 783 53 e-27 0.000 000 11 e-27 J T^-1 nuclear magneton in eV/T 3.152 451 2605 e-8 0.000 000 0022 e-8 eV T^-1 nuclear magneton in inverse meters per tesla 2.542 623 527 e-2 0.000 000 056 e-2 m^-1 T^-1 nuclear magneton in K/T 3.658 2682 e-4 0.000 0033 e-4 K T^-1 nuclear magneton in MHz/T 7.622 593 57 0.000 000 17 MHz T^-1 Planck constant 6.626 069 57 e-34 0.000 000 29 e-34 J s Planck constant in eV s 4.135 667 516 e-15 0.000 000 091 e-15 eV s Planck constant over 2 pi 1.054 571 726 e-34 0.000 000 047 e-34 J s Planck constant over 2 pi in eV s 6.582 119 28 e-16 0.000 000 15 e-16 eV s Planck constant over 2 pi times c in MeV fm 197.326 9718 0.000 0044 MeV fm Planck length 1.616 199 e-35 0.000 097 e-35 m Planck mass 2.176 51 e-8 0.000 13 e-8 kg Planck mass energy equivalent in GeV 1.220 932 e19 0.000 073 e19 GeV Planck temperature 1.416 833 e32 0.000 085 e32 K Planck time 5.391 06 e-44 0.000 32 e-44 s proton charge to mass quotient 9.578 833 58 e7 0.000 000 21 e7 C kg^-1 proton Compton wavelength 1.321 409 856 23 e-15 0.000 000 000 94 e-15 m proton Compton wavelength over 2 pi 0.210 308 910 47 e-15 0.000 000 000 15 e-15 m proton-electron mass ratio 1836.152 672 45 0.000 000 75 proton g factor 5.585 694 713 0.000 000 046 proton gyromag. ratio 2.675 222 005 e8 0.000 000 063 e8 s^-1 T^-1 proton gyromag. ratio over 2 pi 42.577 4806 0.000 0010 MHz T^-1 proton mag. mom. 1.410 606 743 e-26 0.000 000 033 e-26 J T^-1 proton mag. mom. to Bohr magneton ratio 1.521 032 210 e-3 0.000 000 012 e-3 proton mag. mom. to nuclear magneton ratio 2.792 847 356 0.000 000 023 proton mag. shielding correction 25.694 e-6 0.014 e-6 proton mass 1.672 621 777 e-27 0.000 000 074 e-27 kg proton mass energy equivalent 1.503 277 484 e-10 0.000 000 066 e-10 J proton mass energy equivalent in MeV 938.272 046 0.000 021 MeV proton mass in u 1.007 276 466 812 0.000 000 000 090 u proton molar mass 1.007 276 466 812 e-3 0.000 000 000 090 e-3 kg mol^-1 proton-muon mass ratio 8.880 243 31 0.000 000 22 proton-neutron mag. mom. ratio -1.459 898 06 0.000 000 34 proton-neutron mass ratio 0.998 623 478 26 0.000 000 000 45 proton rms charge radius 0.8775 e-15 0.0051 e-15 m proton-tau mass ratio 0.528 063 0.000 048 quantum of circulation 3.636 947 5520 e-4 0.000 000 0024 e-4 m^2 s^-1 quantum of circulation times 2 7.273 895 1040 e-4 0.000 000 0047 e-4 m^2 s^-1 Rydberg constant 10 973 731.568 539 0.000 055 m^-1 Rydberg constant times c in Hz 3.289 841 960 364 e15 0.000 000 000 017 e15 Hz Rydberg constant times hc in eV 13.605 692 53 0.000 000 30 eV Rydberg constant times hc in J 2.179 872 171 e-18 0.000 000 096 e-18 J Sackur-Tetrode constant (1 K, 100 kPa) -1.151 7078 0.000 0023 Sackur-Tetrode constant (1 K, 101.325 kPa) -1.164 8708 0.000 0023 second radiation constant 1.438 7770 e-2 0.000 0013 e-2 m K shielded helion gyromag. ratio 2.037 894 659 e8 0.000 000 051 e8 s^-1 T^-1 shielded helion gyromag. ratio over 2 pi 32.434 100 84 0.000 000 81 MHz T^-1 shielded helion mag. mom. -1.074 553 044 e-26 0.000 000 027 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 -2.127 497 718 0.000 000 025 shielded helion to proton mag. mom. ratio -0.761 766 558 0.000 000 011 shielded helion to shielded proton mag. mom. ratio -0.761 786 1313 0.000 000 0033 shielded proton gyromag. ratio 2.675 153 268 e8 0.000 000 066 e8 s^-1 T^-1 shielded proton gyromag. ratio over 2 pi 42.576 3866 0.000 0010 MHz T^-1 shielded proton mag. mom. 1.410 570 499 e-26 0.000 000 035 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 2.792 775 598 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 5.670 373 e-8 0.000 021 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 8734 e-28 0.000 000 0013 e-28 m^2 triton-electron mass ratio 5496.921 5267 0.000 0050 triton g factor 5.957 924 896 0.000 000 076 triton mag. mom. 1.504 609 447 e-26 0.000 000 038 e-26 J T^-1 triton mag. mom. to Bohr magneton ratio 1.622 393 657 e-3 0.000 000 021 e-3 triton mag. mom. to nuclear magneton ratio 2.978 962 448 0.000 000 038 triton mass 5.007 356 30 e-27 0.000 000 22 e-27 kg triton mass energy equivalent 4.500 387 41 e-10 0.000 000 20 e-10 J triton mass energy equivalent in MeV 2808.921 005 0.000 062 MeV triton mass in u 3.015 500 7134 0.000 000 0025 u triton molar mass 3.015 500 7134 e-3 0.000 000 0025 e-3 kg mol^-1 triton-proton mass ratio 2.993 717 0308 0.000 000 0025 unified atomic mass unit 1.660 538 921 e-27 0.000 000 073 e-27 kg von Klitzing constant 25 812.807 4434 0.000 0084 ohm weak mixing angle 0.2223 0.0021 Wien frequency displacement law constant 5.878 9254 e10 0.000 0053 e10 Hz K^-1 Wien wavelength displacement law constant 2.897 7721 e-3 0.000 0026 e-3 m K