Physical Constants & Units Conversion 2010
A. Miyoshi
Back

Physical Constants & Units Conversion (old 2010 version)

Physical Constants (old version CODATA 2010) and SI Units

Here, a brief summary of physical constants based on   P.J. Mohr, B.N. Taylor, and D.B. Newell (2011), "The 2010 CODATA Recommended Values of the Fundamental Physical Constants" (Web Version 6.0). This database was developed by J. Baker, M. Douma, and S. Kotochigova. Available: http://physics.nist.gov/constants [Friday, 22-Jul-2011 10:04:27 EDT]. National Institute of Standards and Technology, Gaithersburg, MD 20899.   is shown. For detail, see, Fundamental Physical Constants from NIST.

Mathematical Constant

π 3.14159265358979323846

Fundamental Physical Constants (2010 CODATA)

Value UnitRel. std.
uncert.		 Quantity
c0 299 792 458
= 2.997 924 58×108		 m s−1(exact) speed of light
in vacuum
h 6.626 069 57(29)×10−34 J s4.4×10−8 Planck constant
e 1.602 176 565(35)×10−19 C2.2×10−8 elementary charge
NA 6.022 141 29(27)×1023 mol−14.4×10−8 Avogadro constant
me 9.109 382 91(40)×10−31 kg4.4×10−8 electron mass
R 8.314 4621(15) J K−1 mol−1 9.1×10−7 molar gas constant
G 6.673 84(80)×10−11 m3 kg−1 s−2 1.2×10−4 Newtonian constant
of gravitation

Physical Constants

- though with an apparent relation to fundamental constants, known more accurate than derived from them

Derived as Value Unit Rel. std.
uncert.		 Quantity
R∞ mec0α2 / 2h 10 973 731.568 539(55)
= 1.097 373 156 8539(55)×107		 m−1 5.0×10−12 Rydberg constant
α μ0c0e2 / 2h 7.297 352 5698(24)×10−3 –3.2×10−10 fine structure
constant
F NAe 96 485.3365(21)
= 9.648 533 65(21)×104		 C mol−12.2×10−8 Faraday constant
μB eh / 4πme 927.400 968(20)×10−26 J T−12.2×10−8 Bohr magneton

Physical Constants

- derived from fundamental mathematical / physical constants

Derived as Value Unit Rel. std.
uncert.		 Quantity
μ0 4π×10−7 ~ 12.566 370 614×10−7 H m−1
(N A−2)		(exact) magnetic constant
ε0 1 / μ0c02 ~ 8.854 187 818×10−12 F m−1(exact) electric constant
ħ h / 2π 1.054 571 725(47)×10−34 J s4.4×10−8
mu 10−3 / NA 1.660 538 921(73)×10−27 kg4.4×10−8 atomic mass constant
k R / NA 1.380 6488(13)×10−23 J K−19.1×10−7 Boltzmann constant
a0 α / 4πR∞ 0.529 177 210 92(17)×10−10 m3.2×10−10 Bohr radius
Eh 2R∞hc0 4.359 744 34(19)×10−18 J4.4×10−8 Hartree energy

SI Derived Units with Special Names

Derived QuatitySymbol Expression
in terms of
other SI units		 Expression
in terms of
SI base units
electric chargeC A s
electric potentialV J C−1m2 kg s−3 A−1
electric capacitanceF C V−1m−2 kg−1 s4 A2
Celsius temperature °C θ / °C + 273.15 ≡ T / K

Conversion of Units

Non-SI Units

Quantity
pressure 1 bar ≡ 105 Pa
1 atm ≡ 101 325 Pa
1 Torr ≡ 1 / 760 atm ~ 133.322 3684 Pa
energy1 cal ≡ 4.184 J
cross section1 b (barn) ≡ 1 × 10−28 m2