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Physical Constants
Submitted by satya on Mon, 19/02/2007 - 15:56.
Various types of constants have been defined in physics, which we use for performing various calculations. These constants are from various branches of science and are mostly universal in nature. (Except some like acceleration due to gravity on Earth, which changes from place to place).
| quantity | symbol | value |
|---|---|---|
| acceleration due to gravity | g | 9.806 65 m/s2 |
| age of Universe | t0 | 15(5) Gy |
| atomic mass unit, unified | u | 931.494 32(28) MeV/c2
= 1.660 540 2(10) x 10-27 kg |
| astronomical unit | au | 1.495 978 706 6(2) x 1011 m |
| Avogadro constant | NA | 6.022 136 7(36) x 1023 mol-1 |
| Bohr magneton | muB | 5.788 382 63(52) x 10-11 MeV/T |
| Bohr radius | aoo | 0.529 177 249(24) x 10-10 m |
| Boltzmann constant | k | 1.380 658(12) x 10-23 J/K = 8.617 385(73) x 10-5 eV/K |
| cosmic background energy density | rhogamma | 4.647 7 x 10-34 (T/2.726
K)4 g/cm3 = 0.260 71 (T/2.726 K)4 eV/cm3 |
| cosmic background number density | ngamma | 410.89 (T/2.726 K)3 cm-3 |
| cosmic background temperature | T0 | 2.726 +- 0.005 K |
| critical density of Universe | rhoc | 2.775 366 27 x 1011 h02
MS Mpc-3
= 1.878 82(24) x 10-29 h02 g/cm3 = 1.053 94(13) x 10-5 h02 GeV/cm3 |
| day, mean sidereal | dsidereal | 23h 56m 04s.090 53 |
| deuteron (2H) mass | md | 1875.613 39(57) MeV/c2 |
| Earth mass | ME | 5.973 70(76) x 1024 kg |
| Earth radius (equatorial) | RE | 6.378 140 x 106 m |
| electron charge magnitude | e | 1.602 177 33(49) x 10-19 C = 4.803 206 8(15) x 10-10 esu |
| electron mass | me | 0.510 999 06(15) MeV/c2
= 9.109 389 7(54) x 10-31 kg |
| electron radius, classical | re | 2.817 940 92(38) x 10-15 m |
| electron Compton wavelength | lambdabare | 3.861 593 23(35) x 10-13 m |
| entropy density/Boltzmann constant | s/k | 2.892 4 (T/2.726 K)3 cm-3 |
| fine structure constant | alpha | 1/137.035 989 5(61) |
| gravitational constant | GN | 6.672 59(85) x 10-11 m3/(kg
s2) = 6.707 11(86) x 10-39 h c/(GeV/c2)2 |
| Hubble constant | H0 | 100 h0
km/(s Mpc) = h0/9.778 13 Gy |
| Hubble constant, normalized | h0 | 0.5 < h0 < 0.85 |
| jansky | Jy | 10-26 W/(m2 Hz) |
| light year (deprecated) | ly | 0.306 6... pc = 0.946 1... x 1016 m |
| Naperian (natural) logarithm base | e | 2.718 281 828 459 045 235 |
| nuclear magneton | muN | 3.152 451 66(28) x 10-14 MeV/T |
| parsec (au/arcsec) | pc | 3.085
677 580 7(4) x 1016 m = 3.262... ly |
| permeability of free space | mu0 | 4 pi x 10-7
N/A2 = 12.566 370 614... x 10-7 N/A2 |
| permittivity of free space | epsilon0 | 8.854 187 817... x 10-12 F/m |
| pi | pi | 3.141 592 653 589 793 238 |
| Planck constant | h | 6.626 075 5(40) x 10-34 J s |
| Planck constant, reduced | hbar | 1.054 572 66(63) x 10-34 J
s = 6.582 122 0(20) x 10-22 MeV s |
| Planck mass | mP | 1.221 047(79) x 1019 GeV/c2
= 2.176 71(14) x 10-8 kg |
| proton (1H) mass | mp | 938.272 31(28) MeV/c2
= 1.672 623 1(10) x 10-27 kg = 1.007 276 470(12) u = 1836.152 701(37) me |
| Rydberg energy | h c Roo | 13.605 698 1(40) eV |
| Schwarzschild radius of Sun | 2 GN MS/c2 | 2.953 250 08 km |
| speed of light in vacuum | c | 299 792 458 m/s |
| Stefan-Boltzmann constant | sigma | 5.670 51(19) x 10-8 W/(m2 K4) |
| strong coupling constant | alphas | 0.118(3) |
| Sun distance from Core | Ro | 8.0(5) kpc |
| Sun luminosity | LS | 3.846 x 1026 W |
| Sun mass | MS | 1.988 92(25) x 1030 kg |
| Sun radius (equatorial) | RS | 6.96 x 108 m |
| Sun speed around Core | Thetao | 220(20) km/s |
| Sun speed to cosmic background | 369.5 +- 3.0 km/s | |
| Thompson cross section | sigmaT | 0.665 246 16(18) barn |
| W+- boson mass | mW | 80.33(15) GeV/c2 |
| Wien displacement law constant | b | 2.897 756(24) x 19) x 10-3 m K |
| year, sidereal (fixed star to fixed star, 1994) | ysidereal | 31 558 149.8 s |
| year, tropical (equinox to equinox, 1994) | y | 31 556 925.2 s |
| Z0 boson mass | mZ | 91.187(7) GeV/c2 |
