# Physic Constants

| Name                             | Symbol                                            | Value                                                                      |
| -------------------------------- | ------------------------------------------------- | -------------------------------------------------------------------------- |
| Electron Charge                  | $$e$$                                             | $$1.602176565(35) \times 10^{-19}$$                                        |
| Speed of light                   | $$c$$                                             | $$299 792 458 {\rm; m/s}$$                                                 |
| Avogadro Number                  | $$N\_A$$                                          | $$6.02214129(27) \times 10^{23} \textrm{mol}^{-1}$$                        |
| Planck's Constant                | $$h$$                                             | $$6.6260693 \times 10^{-34} \textrm{Js}$$                                  |
| Reduce Planck's Constant         | $$\hbar =\frac{h}{2\pi}$$                         | $$1.054 \times 10^{-34} \textrm{Js} = 6.582 \times 10^{-25} \textrm{GeV}$$ |
| Boltzmann constant               | $$k\_B$$                                          | $$1.38 \times 10^{-23} \textrm{JK}^{-1}$$                                  |
| Fine structure constant          | $$\alpha = \frac{e^2}{4\pi \epsilon\_0 \hbar c}$$ | $$\frac{1}{137}$$                                                          |
| Classical radius of the electron | $$r\_e = \frac{e^2}{4\pi \epsilon\_0 Im\_ec^2}$$  | $$2.817 940 3227 \times 10^{-15} {\rm;  m}$$                               |

De Broglie wavelength $$\lambda = \frac{h}{p}$$ and energy of a photon $$E = hf = \frac{hc}{\lambda} = \frac{1240 \rm eV nm}{\lambda (\rm nm)}$$, where f is the frequency and $$\lambda$$ the corresponding wavelength.

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