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[Physics Constants]

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Overview

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The table below lists the most commonly used physics constants.
  

Physics Constants

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Constant

Value

Unit

speed of light in vacuum

299 792 458

m s-1

magn. constant

12.566 370 614 e-7

N A-2

electric constant

8.854 187 817 e-12

F m-1

characteristic impedance of vacuum

376.730 313 461

ohm

Newtonian constant of gravitation

0.000000000066742

m3 kg-1 s-2

Newtonian constant of gravitation over h-bar c

6.7087E-039

(GeV/c2)-2

Planck constant

6.626 0693e-34

J s

Planck constant in eV s

4.135 667 43e-15

eV s

Planck constant over 2 pi times c in MeV fm

197.326 968

MeV fm

Planck constant over 2 pi

1.054 571 68e-34

J s

Planck constant over 2 pi in eV s

6.582 119 15e-16

eV s

Planck mass

2.176 45e-8

kg

Planck temperature

1.416 79e32

K

Planck length

1.616 24e-35

m

Planck time

5.391 21e-44

s

elementary charge

1.602 176 53e-19

C

elementary charge over h

2.417 989 40e14

A J-1

magn. flux quantum

2.067 833 72e-15

Wb

conductance quantum

7.748 091 733e-5

S

inverse of conductance quantum

12 906.403 725

ohm

Josephson constant

483 597.879e9

Hz V-1

von Klitzing constant

25 812.807 449

ohm

Bohr magneton

927.400 949e-26

J T-1

Bohr magneton in eV/T

5.788 381 804e-5

eV T-1

Bohr magneton in Hz/T

13.996 2458e9

Hz T-1

Bohr magneton in inverse meters per tesla

46.686 4507

m-1 T-1

Bohr magneton in K/T

0.671 7131

K T-1

nuclear magneton

5.050 783 43e-27

J T-1

nuclear magneton in eV/T

3.152 451 259e-8

eV T-1

nuclear magneton in MHz/T

7.622 593 71

MHz T-1

nuclear magneton in inverse meters per tesla

2.542 623 58e-2

m-1 T-1

nuclear magneton in K/T

3.658 2637e-4

K T-1

fine-structure constant

7.297 352 568e-3

 

inverse fine-structure constant

137.035 999 11

 

Rydberg constant

10 973 731.568 525

m-1

Rydberg constant times c in Hz

3.289 841 960 360e15

Hz

Rydberg constant times hc in J

2.179 872 09e-18

J

Rydberg constant times hc in eV

13.605 6923

eV

Bohr radius

0.529 177 2108e-10

m

Hartree energy

4.359 744 17e-18

J

Hartree energy in eV

27.211 3845

eV

quantum of circulation

3.636 947 550e-4

m2 s-1

quantum of circulation times 2

7.273 895 101e-4

m2 s-1

Fermi coupling constant

1.166 39e-5

GeV-2

weak mixing angle

0.222 15

 

electron mass

9.109 3826e-31

kg

electron mass in u

5.485 799 0945e-4

u

electron mass energy equivalent

8.187 1047e-14

J

electron mass energy equivalent in MeV

0.510 998 918

MeV

electron-muon mass ratio

4.836 331 67e-3

 

electron-tau mass ratio

2.875 64e-4

 

electron-proton mass ratio

5.446 170 2173e-4

 

electron-neutron mass ratio

5.438 673 4481e-4

 

electron-deuteron mass ratio

2.724 437 1095e-4

 

electron to alpha particle mass ratio

1.370 933 555 75e-4

 

electron charge to mass quotient

-1.758 820 12e11

C kg-1

electron molar mass

5.485 799 0945e-7

kg mol-1

Compton wavelength

2.426 310 238e-12

m

Compton wavelength over 2 pi

386.159 2678e-15

m

classical electron radius

2.817 940 325e-15

m

Thomson cross section

0.665 245 873e-28

m2

electron magn. moment

-928.476 412e-26

J T-1

electron magn. moment to Bohr magneton ratio

-1.001 159 652 1859

 

electron magn. moment to nuclear magneton ratio

-1838.281 971 07

 

electron magn. moment anomaly

1.159 652 1859e-3

 

electron g factor

-2.002 319 304 3718

 

electron-muon magn. moment ratio

206.766 9894

 

electron-proton magn. moment ratio

-658.210 6862

 

electron to shielded proton magn. moment ratio

-658.227 5956

 

electron-neutron magn. moment ratio

960.920 50

 

electron-deuteron magn. moment ratio

-2143.923 493

 

electron to shielded helion magn. moment ratio

864.058 255

 

electron gyromagn. ratio

1.760 859 74e11

s-1 T-1

electron gyromagn. ratio over 2 pi

28 024.9532

MHz T-1

muon mass

1.883 531 40e-28

kg

muon mass in u

0.113 428 9264

u

muon mass energy equivalent

1.692 833 60e-11

J

muon mass energy equivalent in MeV

105.658 3692

MeV

muon-electron mass ratio

206.768 2838

 

muon-tau mass ratio

5.945 92e-2

 

muon-proton mass ratio

0.112 609 5269

 

muon-neutron mass ratio

0.112 454 5175

 

muon molar mass

0.113 428 9264e-3

kg mol-1

muon Compton wavelength

11.734 441 05e-15

m

muon Compton wavelength over 2 pi

1.867 594 298e-15

m

muon magn. moment

-4.490 447 99e-26

J T-1

muon magn. moment to Bohr magneton ratio

-4.841 970 45e-3

 

muon magn. moment to nuclear magneton ratio

-8.890 596 98

 

muon magn. moment anomaly

1.165 919 81e-3

 

muon g factor

-2.002 331 8396

 

muon-proton magn. moment ratio

-3.183 345 118

 

tau mass

3.167 77e-27

kg

tau mass in u

1.907 68

u

tau mass energy equivalent

0.000000000284705

J

tau mass energy equivalent in MeV

1776.99

MeV

tau-electron mass ratio

3477.48

 

tau-muon mass ratio

16.8183

 

tau-proton mass ratio

1.893 90

 

tau-neutron mass ratio

1.891 29

 

tau molar mass

1.907 68e-3

kg mol-1

tau Compton wavelength

0.697 72e-15

m

tau Compton wavelength over 2 pi

0.111 046e-15

m

proton mass

1.672 621 71e-27

kg

proton mass in u

1.007 276 466 88

u

proton mass energy equivalent

1.503 277 43e-10

J

proton mass energy equivalent in MeV

938.272 029

MeV

proton-electron mass ratio

1836.152 672 61

 

proton-muon mass ratio

8.880 243 33

 

proton-tau mass ratio

0.528 012

 

proton-neutron mass ratio

0.998 623 478 72

 

proton charge to mass quotient

9.578 833 76e7

C kg-1

proton molar mass

1.007 276 466 88e-3

kg mol-1

proton Compton wavelength

1.321 409 8555e-15

m

proton Compton wavelength over 2 pi

0.210 308 9104e-15

m

proton magn. moment

1.410 606 71e-26

J T-1

proton magn. moment to Bohr magneton ratio

1.521 032 206e-3

 

proton magn. moment to nuclear magneton ratio

2.792 847 351

 

proton g factor

5.585 694 701

 

proton-neutron magn. moment ratio

-1.459 898 05

 

shielded proton magn. moment

1.410 570 47e-26

J T-1

shielded proton magn. moment to Bohr magneton ratio

1.520 993 132e-3

 

shielded proton magn. moment to nuclear magneton ratio

2.792 775 604

 

proton magn. shielding correction

0.000025689

 

proton gyromagn. ratio

2.675 222 05e8

s-1 T-1

proton gyromagn. ratio over 2 pi

42.577 4813

MHz T-1

shielded proton gyromagn. ratio

2.675 153 33e8

s-1 T-1

shielded proton gyromagn. ratio over 2 pi

42.576 3875

MHz T-1

proton rms charge radius

8.75E-016

m

neutron mass

1.674 927 28e-27

kg

neutron mass in u

1.008 664 915 60

u

neutron mass energy equivalent

1.505 349 57e-10

J

neutron mass energy equivalent in MeV

939.565 360

MeV

neutron-electron mass ratio

1838.683 6598

 

neutron-muon mass ratio

8.892 484 02

 

neutron-tau mass ratio

0.528 740

 

neutron-proton mass ratio

1.001 378 418 70

 

neutron molar mass

1.008 664 915 60e-3

kg mol-1

neutron Compton wavelength

1.319 590 9067e-15

m

neutron Compton wavelength over 2 pi

0.210 019 4157e-15

m

neutron magn. moment

-0.966 236 45e-26

J T-1

neutron magn. moment to Bohr magneton ratio

-1.041 875 63e-3

 

neutron magn. moment to nuclear magneton ratio

-1.913 042 73

 

neutron g factor

-3.826 085 46

 

neutron-electron magn. moment ratio

1.040 668 82e-3

 

neutron-proton magn. moment ratio

-0.684 979 34

 

neutron to shielded proton magn. moment ratio

-0.684 996 94

 

neutron gyromagn. ratio

1.832 471 83e8

s-1 T-1

neutron gyromagn. ratio over 2 pi

29.164 6950

MHz T-1

deuteron mass

3.343 583 35e-27

kg

deuteron mass in u

2.013 553 212 70

u

deuteron mass energy equivalent

3.005 062 85e-10

J

deuteron mass energy equivalent in MeV

1875.612 82

MeV

deuteron-electron mass ratio

3670.482 9652

 

deuteron-proton mass ratio

1.999 007 500 82

 

deuteron molar mass

2.013 553 212 70e-3

kg mol-1

deuteron magn. moment

0.433 073 482e-26

J T-1

deuteron magn. moment to Bohr magneton ratio

0.466 975 4567e-3

 

deuteron magn. moment to nuclear magneton ratio

0.857 438 2329

 

deuteron-electron magn. moment ratio

-4.664 345 548e-4

 

deuteron-proton magn. moment ratio

0.307 012 2084

 

deuteron-neutron magn. moment ratio

-0.448 206 52

 

deuteron rms charge radius

2.1394E-015

m

helion mass

5.006 412 14e-27

kg

helion mass in u

3.014 932 2434

u

helion mass energy equivalent

4.499 538 84e-10

J

helion mass energy equivalent in MeV

2808.391 42

MeV

helion-electron mass ratio

5495.885 269

 

helion-proton mass ratio

2.993 152 6671

 

helion molar mass

3.014 932 2434e-3

kg mol-1

shielded helion magn. moment

-1.074 553 024e-26

J T-1

shielded helion magn. moment to Bohr magneton ratio

-1.158 671 474e-3

 

shielded helion magn. moment to nuclear magneton ratio

-2.127 497 723

 

shielded helion to proton magn. moment ratio

-0.761 766 562

 

shielded helion to shielded proton magn. moment ratio

-0.761 786 1313

 

shielded helion gyromagn. ratio

2.037 894 70e8

s-1 T-1

shielded helion gyromagn. ratio over 2 pi

32.434 1015

MHz T-1

alpha particle mass

6.644 6565e-27

kg

alpha particle mass in u

4.001 506 179 149

u

alpha particle mass energy equivalent

5.971 9194e-10

J

alpha particle mass energy equivalent in MeV

3727.379 17

MeV

alpha particle-electron mass ratio

7294.299 5363

 

alpha particle-proton mass ratio

3.972 599 689 07

 

alpha particle molar mass

4.001 506 179 149e-3

kg mol-1

Avogadro constant

6.022 1415e23

mol-1

atomic mass constant

1.660 538 86e-27

kg

atomic mass constant energy equivalent

1.492 417 90e-10

J

atomic mass constant energy equivalent in MeV

931.494 043

MeV

Faraday constant

96 485.3383

C mol-1

Faraday constant for conventional electric current

96 485.336

C_90 mol-1

molar Planck constant

3.990 312 716e-10

J s mol-1

molar Planck constant times c

0.119 626 565 72

J m mol-1

molar gas constant

8.314 472

J mol-1 K-1

Boltzmann constant

1.380 6505e-23

J K-1

Boltzmann constant in eV/K

8.617 343e-5

eV K-1

Boltzmann constant in Hz/K

2.083 6644e10

Hz K-1

Boltzmann constant in inverse meters per kelvin

69.503 56

m-1 K-1

molar volume of ideal gas (273.15 K, 101.325 kPa)

22.413 996e-3

m3 mol-1

Loschmidt constant (273.15 K, 101.325 kPa)

2.686 7773e25

m-3

molar volume of ideal gas (273.15 K, 100 kPa)

22.710 981e-3

m3 mol-1

Sackur-Tetrode constant (1 K, 100 kPa)

-1.151 7047

 

Sackur-Tetrode constant (1 K, 101.325 kPa)

-1.164 8677

 

Stefan-Boltzmann constant

5.670 400e-8

W m-2 K-4

first radiation constant

3.741 771 38e-16

W m2

first radiation constant for spectral radiance

1.191 042 82e-16

W m2 sr-1

second radiation constant

1.438 7752e-2

m K

Wien displacement law constant

2.897 7685e-3

m K

molar mass of carbon-12

0.012

kg mol-1

molar mass constant

0.001

kg mol-1

conventional value of Josephson constant

483 597.9e9

Hz V-1

conventional value of von Klitzing constant

25 812.807

ohm

standard atmosphere

101 325

Pa

standard acceleration of gravity

9.806 65

m s-2

Cu x unit

1.002 077 10e-13

m

Mo x unit

1.002 099 66e-13

m

Angstrom star

1.000 015 09e-10

m

lattice parameter of silicon

543.102 122e-12

m

{220} lattice spacing of silicon

192.015 5965e-12

m

molar volume of silicon

12.058 8382e-6

m3 mol-1

electron volt

1.602 176 53e-19

J

unified atomic mass unit

1.660 538 86e-27

kg

natural unit of velocity

299 792 458

m s-1

natural unit of action

1.054 571 68e-34

J s

natural unit of action in eV s

6.582 119 15e-16

eV s

natural unit of mass

9.109 3826e-31

kg

natural unit of energy

8.187 1047e-14

J

natural unit of energy in MeV

0.510 998 918

MeV

natural unit of momentum

2.730 924 19e-22

kg m s-1

natural unit of momentum in MeV/c

0.510 998 918

MeV/c

natural unit of length

386.159 2678e-15

m

natural unit of time

1.288 088 6677e-21

s

atomic unit of charge

1.602 176 53e-19

C

atomic unit of mass

9.109 3826e-31

kg

atomic unit of action

1.054 571 68e-34

J s

atomic unit of length

0.529 177 2108e-10

m

atomic unit of energy

4.359 744 17e-18

J

atomic unit of time

2.418 884 326 505e-17

s

atomic unit of force

8.238 7225e-8

N

atomic unit of velocity

2.187 691 2633e6

m s-1

atomic unit of momentum

1.992 851 66e-24

kg m s-1

atomic unit of current

6.623 617 82e-3

A

atomic unit of charge density

1.081 202 317e12

C m-3

atomic unit of electric potential

27.211 3845

V

atomic unit of electric field

5.142 206 42e11

V m-1

atomic unit of electric field gradient

9.717 361 82e21

V m-2

atomic unit of electric dipole moment

8.478 353 09e-30

C m

atomic unit of electric quadrupole moment

4.486 551 24e-40

C m2

atomic unit of electric polarizablity

1.648 777 274e-41

C2 m2 J-1

atomic unit of 1st hyperpolarizablity

3.206 361 51e-53

C3 m3 J-2

atomic unit of 2nd hyperpolarizablity

6.235 3808e-65

C4 m4 J-3

atomic unit of magn. flux density

2.350 517 42e5

T

atomic unit of magn. dipole moment

1.854 801 90e-23

J T-1

atomic unit of magnetizability

7.891 036 60e-29

J T-2

atomic unit of permittivity

1.112 650 056...e-10

F m-1

joule-kilogram relationship

1.112 650 056...e-17

kg

joule-inverse meter relationship

5.034 117 20e24

m-1

joule-hertz relationship

1.509 190 37e33

Hz

joule-kelvin relationship

7.242 963e22

K

joule-electron volt relationship

6.241 509 47e18

eV

joule-atomic mass unit relationship

6.700 5361e9

u

joule-hartree relationship

2.293 712 57e17

E_h

kilogram-joule relationship

8.987 551 787...e16

J

kilogram-inverse meter relationship

4.524 438 91e41

m-1

kilogram-hertz relationship

1.356 392 66e50

Hz

kilogram-kelvin relationship

6.509 650e39

K

kilogram-electron volt relationship

5.609 588 96e35

eV

kilogram-atomic mass unit relationship

6.022 1415e26

u

kilogram-hartree relationship

2.061 486 05e34

E_h

inverse meter-joule relationship

1.986 445 61e-25

J

inverse meter-kilogram relationship

2.210 218 81e-42

kg

inverse meter-hertz relationship

299 792 458

Hz

inverse meter-kelvin relationship

1.438 7752e-2

K

inverse meter-electron volt relationship

1.239 841 91e-6

eV

inverse meter-atomic mass unit relationship

1.331 025 0506e-15

u

inverse meter-hartree relationship

4.556 335 252 760e-8

E_h

hertz-joule relationship

6.626 0693e-34

J

hertz-kilogram relationship

7.372 4964e-51

kg

hertz-inverse meter relationship

3.335 640 951...e-9

m-1

hertz-kelvin relationship

4.799 2374e-11

K

hertz-electron volt relationship

4.135 667 43e-15

eV

hertz-atomic mass unit relationship

4.439 821 667e-24

u

hertz-hartree relationship

1.519 829 846 006e-16

E_h

kelvin-joule relationship

1.380 6505e-23

J

kelvin-kilogram relationship

1.536 1808e-40

kg

kelvin-inverse meter relationship

69.503 56

m-1

kelvin-hertz relationship

2.083 6644e10

Hz

kelvin-electron volt relationship

8.617 343e-5

eV

kelvin-atomic mass unit relationship

9.251 098e-14

u

kelvin-hartree relationship

3.166 8153e-6

E_h

electron volt-joule relationship

1.602 176 53e-19

J

electron volt-kilogram relationship

1.782 661 81e-36

kg

electron volt-inverse meter relationship

8.065 544 45e5

m-1

electron volt-hertz relationship

2.417 989 40e14

Hz

electron volt-kelvin relationship

1.160 4505e4

K

electron volt-atomic mass unit relationship

1.073 544 171e-9

u

electron volt-hartree relationship

3.674 932 45e-2

E_h

atomic mass unit-joule relationship

1.492 417 90e-10

J

atomic mass unit-kilogram relationship

1.660 538 86e-27

kg

atomic mass unit-inverse meter relationship

7.513 006 608e14

m-1

atomic mass unit-hertz relationship

2.252 342 718e23

Hz

atomic mass unit-kelvin relationship

1.080 9527e13

K

atomic mass unit-electron volt relationship

931.494 043e6

eV

atomic mass unit-hartree relationship

3.423 177 686e7

E_h

hartree-joule relationship

4.359 744 17e-18

J

hartree-kilogram relationship

4.850 869 60e-35

kg

hartree-inverse meter relationship

2.194 746 313 705e7

m-1

hartree-hertz relationship

6.579 683 920 721e15

Hz

hartree-kelvin relationship

3.157 7465e5

K

hartree-electron volt relationship

27.211 3845

eV

hartree-atomic mass unit relationship

2.921 262 323e-8

u