Physical Constants
- Page ID
- 27957
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| Name | Symbol | Value | Unit |
|---|---|---|---|
| Number \(\pi\) | \(\pi\) | 3.14159265358979323846 | |
| Number e | e | 2.71828182845904523536 | |
| Euler’s constant | 0.577215664901532860606 | ||
| 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 | \(\alpha=e^2/2hc\varepsilon_0\) | \(\approx1/137\) | |
| 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 | \(\hbar=h/2\pi\) | \(1.0545727\cdot10^{-34}\) | Js |
| Bohr magneton | \(\mu_{\rm B}=e\hbar/2m_{\rm e}\) | \(9.2741\cdot10^{-24}\) | Am\(^2\) |
| Bohr radius | \(a_0\) | \(0.52918\) | Å |
| Rydberg’s constant | \(Ry\) | 13.595 | eV |
| Electron Compton wavelength | \(\lambda_{\rm Ce}=h/m_{\rm e}c\) | \(2.2463\cdot10^{-12}\) | m |
| Proton Compton wavelength | \(\lambda_{\rm Cp}=h/m_{\rm p}c\) | \(1.3214\cdot10^{-15}\) | 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 gasconstant | \(R\) | 8.31441 | J\(\cdot\)mol\(^{-1}\cdot\)K\(^{-1}\) |
| Avogadro’s constant | \(N_{\rm A}\) | \(6.0221367\cdot10^{23}\) | mol\(^{-1}\) |
| Boltzmann’s constant | \(k=R/N_{\rm A}\) | \(1.380658\cdot10^{-23}\) | 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 | \(m_{\rm u}=\frac{1}{12}m(^{12}_{~6}\)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\(^{-1}\) |