# Fundamental Physical Constants

Following is the list of Fundamental Physical Constants, their symbols, their Values and their Units

 Name Symbol Value Unit Speed of Light $c$ $2.99792458 \times 10^8$ $m/s$ Planck Constant $h$ $6.6260755 \times 10^{-34}$ $J .s$ $h$ $4.1356692 \times 10^{-15}$ $e V . s$ Planck hbar $\hbar$ $1.0545727 \times 10^{-34}$ $J . s$ $\hbar$ $6.582121 \times 10^{-16}$ $e V . s$ Gravitational Constant $G$ $6.67259 \times 10^{-11}$ $m^3 . kg^{-1} . s^{-2}$ Boltzmann Constant $k$ $1.380658 \times 10^{-23}$ $J / K$ $k$ $8.617385 \times 10^{-5}$ $e V / K$ Molar Gas Constant $R$ $8.314510$ $J / mol . K$ Avogadro’s Number $N_A$ $6.0221 \times 10^{23}$ $mol^{-1}$ Charge of Electron $e$ $1.60217733 \times 10^{-19}$ $C$ Permeability of Vacuum $\mu_0$ $4 \pi \times 10^{-7}$ $N / A^2$ Permittivity of Vacuum $\epsilon_0$ $8.854187817 \times 10^{-12}$ $F / m$ Coulomb’s Constant $K = 1 / {4 \pi \epsilon_0}$ $8.987552 \times 10^9$ $N . m^2 / C^2$ Faraday’s Constant $F$ $96485.309$ $C / mol$ Mass of Electron $m_e$ $9.1093897 \times 10^{-31}$ $kg$ $m_e$ $0.51099906$ $M e V / c^2$ Electron Charge-to-Mass Ratio $e / m$ $1.759 \times 10^{11}$ $C / kg$ Mass of Proton $m_p$ $1.6726231 \times 10^{-27}$ $kg$ $m_p$ $938.27231$ $M e V / c^2$ Mass of Neutron $m_n$ $1.6749286 \times 10^{-27}$ $kg$ $m_n$ $939.56563$ $M e V / c^2$ Atomic Mass Unit (AMU) $u$ $1.6605402 \times 10^{-27}$ $kg$ $u$ $931.49432$ $M e V / c^2$ Stephan-Boltzmann Constant $\sigma$ $5.67051 \times 10^{-8}$ $W / m^2 . K^4$ Rydberg’s Constant $R_{\infty}$ $10973731.534$ $m^{-1}$ Bohr Magneton $\mu_B$ $9.2740154 \times 10^{-24}$ $J / T$ $\mu_B$ $5.788382 \times 10^{-5}$ $e V / T$ Flux Quantum $\Phi_0$ $2.067834 \times 10^{-15}$ $T / m^2$ Bohr Radius $a_0$ $0.529177249 \times 10^{-10}$ $m$ Standard Atmosphere $atm$ $101325$ $Pa$ Wien Displacement Constant $b$ $2.897756 \times 10^{-3}$ $m . K$

## Table of Other Useful Physical Constants

 Name Symbol Value Mechanical equivalent of heat $J$ $4.186 ~J ~cal^{-1}$ Standard atmospheric pressure $1 ~atm$ $1.013 \times 10^5 ~Pa$ Absolute zero $0^{\circ}~K$ $-273.15^{\circ} ~C$ Electron Volt $1~e V$ $1.602 \times 10^{-19}~J$ Unified Atomic mass unit $1~u$ $1.661 \times 10^{-27}~kg$ Electron rest energy $m c^2$ $0.511 ~M e V$ Energy equivalent of 1 u $1~u c^2$ $931.5~M e V$ Volume of ideal gas (0°C and 1 atm) $V$ $22.4~L~mol^{-1}$ Acceleration due to gravity (sea level, at equator) $g$ $9.78049~m~s^{-2}$

## Useful Combinations of Physical Units

 Combination Name $h c ~=~ 1.9864 \times 10^{-25}~J . m ~=~ 1239.8~e V . nm$ – $\hbar c ~=~ 3.1615 \times 10^{-26}~J . m ~=~ 197.33~e V . nm$ – $K e^2 ~=~ 2.30708 \times 10^{-28}~J . m ~=~ 1.43996~e V . nm$ Coulomb constant $a_0 ~=~ \frac {\hbar^2} {m_e K e^2} ~=~ 5.2918 \times 10^{-11}~m$ Bohr radius $\alpha ~=~ \frac {e^2} {4 \pi \epsilon_0 \hbar c} ~=~ \frac {K e^2} {\hbar c} \\ \\ ~=~ 0.0072974 ~=~ \frac {1} {137}$ Fine structure constant $\lambda_C ~=~ \frac {h} {m_e c} ~=~ 2.4263 \times 10^{-12} ~m$ Compton wavelength $\mu_B ~=~ \frac {e \hbar} {2 m_e} ~=~ 9.2740154 \times 10^{-24} ~ J / T \\ \\ ~=~ 5.788382 \times 10^{-5} ~ e V / T$ Bohr magneton $\Phi_0 ~=~ \frac {h} {2 e} ~=~ 2.0678 \times 10^{-15} ~ T / m^2$ Magnetic flux quantum