# Table Of Physical Constants

Name Symbol Value Unit
Number $\pi$ $\pi$ 3.14159265358979323846
Number e e 2.71828182845904523536
Euler’s constant $\gamma$ \begin{aligned} \gamma &= \lim\limits_{n\rightarrow\infty}\left(\sum\limits_{k=1}^n 1/k-\ln(n)\right) \\ &= 0.5772156649 \end{aligned}
Elementary charge $e$ $1.60217733\cdot10^{-19}$ C
Gravitational constant $G,\kappa$ $6.67259\cdot10^{-11}$ m$^3$kg$^{-1}$s$^{-2}$
Fine-structure constant $\alpha=\frac{e^{2}}{2hc\epsilon_0}$ $\approx \frac{1}{137}$
Speed of light in vacuum $c$ $2.99792458\cdot10^8$ m/s (def)
Permittivity of the vacuum $\varepsilon_0$ $8.854187\cdot10^{-12}$ F/m
Permeability of the vacuum $\mu_0$ $4\pi\cdot10^{-7}$ H/m
$(4\pi\varepsilon_0)^{-1}$ $8.9876\cdot10^9$ Nm$^2$C$^{-2}$
Planck’s constant $h$ $6.6260755\cdot10^{-34}$ Js
Dirac’s constant $\hbar=\frac{h}{2\pi}$ $1.0545727\cdot10^{-34}$ Js
Bohr magneton $\mu_{\rm B}=\frac{e\hbar}{2m_{\rm e}}$ $9.2741\cdot10^{-24}$ Am$^2$
Bohr radius $a_0$ $0.52918$
Rydberg’s constant $Ry$ 13.595 eV
Electron Compton wavelength $\lambda_{\rm Ce}=\frac{h}{m_{e} c}$ $2.2463\cdot10^{-12}$ m
Proton Compton wavelength $\lambda_{\rm Cp}=\frac{h}{m_{\rm p}c}$ $1.3214\cdot10^{-15}$ m
Reduced mass of the H-atom $\mu_{\rm H}$ $9.1045755\cdot10^{-31}$ kg
Stefan-Boltzmann’s constant $\sigma$ $5.67032\cdot10^{-8}$ Wm$^{-2}$K$^{-4}$
Wien’s constant $k_{\rm W}$ $2.8978\cdot10^{-3}$ mK
Molar gas constant $R$ 8.31441 J$\cdot$mol$^{-1}\cdot$K$^{-1}$
Avogadro’s constant $N_{A}$ $6.0221367\cdot10^{23}$ mol$^{-1}$
Boltzmann’s constant $k=\frac{R}{N_{A}}$ $1.380658\cdot10^{-23}$ J/K
Electron mass $m_{\rm e}$ $9.1093897\cdot10^{-31}$ kg
Proton mass $m_{\rm p}$ $1.6726231\cdot10^{-27}$ kg
Neutron mass $m_{\rm n}$ $1.674954\cdot10^{-27}$ kg
Elementary mass unit $m_{u}=\frac{1}{12}m(^{12}_{6}C)$ $1.6605656\cdot10^{-27}$ kg
Nuclear magneton $\mu_{\rm N}$ $5.0508\cdot10^{-27}$ J/T
Diameter of the Sun $D_\odot$ $1392\cdot10^6$ m
Mass of the Sun $M_\odot$ $1.989\cdot10^{30}$ kg
Rotational period of the Sun $T_\odot$ 25.38 days
Radius of Earth $R_{\rm A}$ $6.378\cdot10^6$ m
Mass of Earth $M_{\rm A}$ $5.976\cdot10^{24}$ kg
Rotational period of Earth $T_{\rm A}$ 23.96 hours
Earth orbital period Tropical year 365.24219879 days
Astronomical unit AU $1.4959787066\cdot10^{11}$ m
Light year lj $9.4605\cdot10^{15}$ m
Parsec pc $3.0857\cdot10^{16}$ m
Hubble constant $H$ $\approx(75\pm25)$ km$\cdot$s$^{-1}\cdot$Mpc$^{-1}$