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

 

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