# Physics Study Guide/Physics constants

# Commonly Used Physical Constants

  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                              $R$                                                                    $8.314\ 472(15)$                                              $\mathrm{J}\ \mathrm{mol}^{-1}\ \mathrm{K}^{-1}$    $1.7\times10^{-6}$
  Boltzmann\'s constant                            $k$                                                                    $1.380\ 650\ 5(24)\times10^{-23}$                             $\mathrm{J}\ \mathrm{K}^{-1}$                       $1.8\times10^{-6}$
  Avogadro\'s Number                               $N_{\text{A}}, L$                                                      $6.022\ 141\ 5(10)\times10^{23}$                              $\mathrm{mol}^{-1}$                                 $1.7\times10^{-7}$
  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                                    $eV$                                                                   $1.602\ 176\ 53(14)\times10^{-19}$                            $\mathrm{J}$                                        $8.7\times10^{-8}$
  Luminous efficacy of monochromatic radiation     $K_{cd}$                                                               $683$                                                         $\mathrm{lm/W}$                                     (exact)
  hyperfine transition frequency of Cs-133         $\Delta\nu_\text{Cs}$                                                  $9\ 192\ 631\ 770$                                            $\mathrm{Hz}$                                       (exact)
  Reduced Planck constant                          $\hbar = h/2\pi$                                                       $1.054\ 571\ 817\times{10}^{-34}$                             $\mathrm{J}\cdot \mathrm{s}$                        (exact)
  atomic mass of Carbon 12                         $m({}^{12}\text{C})$                                                   $1.992\ 646\ 879\ 92(60)\times {10}^{-26}$                    $\mathrm{kg}$                                       
  molar mass of Carbon-12                          $M({}^{12}\text{C}) = N_{\text{A}} m({}^{12}\text{C})$                 $11.999\ 999\ 9958(36)\times{10}^{-3}$                        $\mathrm{kg\cdot {mol}^{-1}}$                       
  atomic mass constant                             $m_{\text{u}} = m({}^{12}\text{C}) / 12 = 1\,\text{Da}$                $1.660\ 539\ 066\ 60(50)\times{10}^{-27}$                     $\mathrm{kg}$                                       
  molar mass constant                              $M_{\text{u}} = M({}^{12}\text{C}) / 12 = N_{\text{A}} m_{\text{u}}$   $0.999\ 999\ 999\ 65(30)\times{10}^{-3}$                      $\mathrm{kg\cdot {mol}^{-1}}$                       
  molar volume of silicon                          $V_{m}(\mathrm{Si})$                                                   $1.205\ 883\ 199(60)\times{10}^{-5}$                          $\mathrm{m^3\cdot {mol}^{-1}}$                      
  molar Planck constant                            $N_{\text{A}} h$                                                       $3.990\ 312\ 712\ldots{10}^{-10}$                             $\mathrm{J\cdot {Hz}^{-1}\cdot{mol}^{-1}}$          
  Stefan-Boltzmann constant                        $\sigma = \pi^2 k_B^4 / 60 \hbar^3 c^2$                                $5.670\ 374\ 419\ldots \times {10}^{-8}$                      $\mathrm{W\cdot m^{-2}\cdot K^{-4}}$                
  first radiation constant                         $c_1 = 2 \pi h c^2$                                                    $3.741\ 771\ 852\ldots{10}^{-16}$                             $\mathrm{W\cdot m^2}$                               
  first radiation constant for spectral radiance   $c_{\text{1L}} = 2 h c^2 / sr$[^1]                                     $1.191\ 042\ 972\ 397\ 188\ 414\ 079\ 4892\times{10}^{-16}$   $\mathrm{W\cdot m^2 {sr}^{-1}}$                     
  second radiation constant                        $c_2 = h c / k_B$                                                      $1.438\ 776\ 877\ldots\times{10}^{-2}$                        $\mathrm{m\cdot K}$                                 
  Wien wavelength displacement constant            $b$                                                                    $2.897\ 771\ 955\ldots \times {10}^{-3}$                      $\mathrm{m\cdot K}$                                 
  Wien frequency displacement constant             $b' = c / b$                                                           $5.878\ 925\ 757\ \times {10}^{10}$                           $\mathrm{Hz \cdot K^{-1}}$                          
  Wien entropy displacement constant               $b_\text{entropy}$                                                     $3.002\ 916\ 077\ldots \times {10}^{-3}$                      $\mathrm{m\cdot K}$                                 
  Faraday constant                                 $F = N_{\text{A}} e$[^2]                                               $96\ 485.332\ 123\ 310\ 0184$                                 $\mathrm{C \cdot {mol}^{-1}}$                       

  : Uncertainty should be read as 1.234(56) =
  1.234$\pm$`<!-- -->`{=html}0.056

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## To Be Merged Into Table

This list is prepared in the format

-   Constant (symbol) : value

------------------------------------------------------------------------

-   Coulomb\'s Law Constant (**k**) : 1/(4 π ε~0~) *=* 9.0 × 10^9^
    N·m^2^/C^2^
-   Faraday constant (**F**) : 96,485 C·mol^−1^
-   Mass of a neutron (**m~n~**) : 1.67495 × 10^−27^ kg
-   Mass of Earth : 5.98 × 10^24^ kg
-   Mass of the Moon : 7.35 × 10^22^ kg
-   Mean radius of Earth : 6.37 × 10^6^ m
-   Mean radius of the Moon : 1.74 × 10^6^ m
-   Dirac\'s Constant (**$\hbar$**) : $h/(2\pi)$ = 1.05457148 × 10^−34^
    J·s
-   Speed of sound in air at STP : 3.31 × 10^2^ m/s
-   Unified Atomic Mass Unit (**u**) : 1.66 × 10^−27^ kg

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# See Also

## Wiki-links

-    Wikipedia Article

## External Links

-   NIST Physics
    Lab


[^1]:
    
[^2]:
    