# Commonly Used Physical Constants

Uncertainty should be read as 1.234(56) = 1.234$\pm$0.056
Name Symbol Value Units Relative Uncertainty
Speed of light (in vacuum) $c$ $299\ 792\ 458$ $\mathrm{m}\ \mathrm{s}^{-1}$ (exact)
Magnetic Constant $\mu_0$ $4\pi\times10^{-7}\approx12.566\ 370\ 6\times10^{-7}$ $\mathrm{N}\ \mathrm{A}^{-2}$ (exact)
Electric Constant $\varepsilon_0 = 1/\left( \mu_0c^2 \right)$ $\approx8.854\ 187\ 817\times10^{-12}$ $\mathrm{F}\ \mathrm{m}^{-1}$ (exact)
Newtonian Gravitaional Constant $G$ $6.674\ 2(10)\times10^{-11}$ $\mathrm{m}^3\ \mathrm{kg}^{-1}\ \mathrm{s}^{-2}$ $1.5\times10^{-4}$
Plank's Constant $h$ $6.626\ 069\ 3(11)\times10^{-34}$ $\mathrm{J}\ \mathrm{s}$ $1.7\times10^{-7}$
Elementary charge $e$ $1.602\ 176\ 53(14)\times10^{-19}$ $\mathrm{C}$ $8.5\times10^{-8}$
Mass of the electron $m_e$ $9.109\ 382\ 6(16)\times10^{-31}$ $\mathrm{kg}$ $1.7\times10^{-7}$
Mass of the proton $m_p$ $1.672\ 621\ 71(29)\times10^{-27}$ $\mathrm{kg}$ $1.7\times10^{-7}$
Fine structure constant $\alpha=\frac{e^2}{4 \pi \varepsilon_0 \hbar c}$ $7.297\ 352\ 568(24)\times10^{-3}$ dimensionless $3.3\times10^{-9}$
Molar gass constant $R$ $8.314\ 472(15)$ $\mathrm{J}\ \mathrm{mol}^{-1}\ \mathrm{K}^{-1}$ $1.7\times10^{-6}$
Boltzman's constant $k$ $1.380\ 650\ 5(24)\times10^{-23}$ $\mathrm{J}\ \mathrm{K}^{-1}$ $1.8\times10^{-6}$
Avogadro's Number $N_A$ $6.022\ 141\ 5(10)\times10^{23}$ $\mathrm{mol}^{-1}$ $1.7\times10^{-7}$
Rydberg constant $R_\infty$ $10\ 973\ 731.568\ 525(73)$ $\mathrm{m}^{-1}$ $6.6\times10^{-12}$
Standard acceleration of gravity $g$ $9.806\ 65$ $\mathrm{m}\ \mathrm{s}^{-2}$ defined
Atmospheric pressure $\mathrm{atm}$ $101\ 325$ $\mathrm{Pa}$ defined
Bohr Radius $a_0\$ $0.529\ 177\ 208\ 59(36)\times10^{-10}\$ $\mathrm{m}\$ $6.8\times10^{-10}$
Electron Volt $eV$ $1.602\ 176\ 53(14)\times10^{-19}$ $\mathrm{J}$ $8.7\times10^{-8}$

## To Be Merged Into Table

This list is prepared in the format

• Constant (symbol) : value

• Coulomb's Law Constant (k) : 1/(4 π ε0) = 9.0 × 109 N·m2/C2
• Faraday constant (F)  : 96,485 C·mol−1
• Mass of a neutron (mn) : 1.67495 × 10−27 kg
• Mass of Earth : 5.98 × 1024 kg
• Mass of the Moon : 7.35 × 1022 kg
• Mean radius of Earth : 6.37 × 106 m
• Mean radius of the Moon : 1.74 × 106 m
• Dirac's Constant ($\hbar$) : $h/(2\pi)$ = 1.05457148 × 10−34 J·s
• Speed of sound in air at STP : 3.31 × 102 m/s
• Unified Atomic Mass Unit (u) : 1.66 × 10−27 kg
 Item Proton Neutron Electron Mass 1 1 Negligible Charge +1 0 -1