A number of physical constants are used throughout physics, as part of the equations used to calculate certain values. This listing is of the values for some of the more significant constants used, along with the variables used to represent them.

## Fundamental Physical Constants

Speed of light | *c* | 2.99792458 x 10^{8} m/s |

Charge of electron | *e* | 1.602177 x 10^{-19} C |

Gravitational constant | *G* | 6.67259 x 10^{-11} N m^{2}/kg^{2} |

Planck's constant | *h* | 6.6260755 x 10^{-34} J s |

Boltzmann's constant | *k* | 1.38066 x 10^{-23} J/K |

Avogadro's number | *N*_{A} | 6.022 x 10^{23} molecules/mol |

Gas constant | *R* | 8.314510 J/mol K |

Mass of electron | *m*_{e} | 9.10939 x 10^{-31} kg |

Mass of neutron | *m*_{n} | 1.67262 x 10^{-27} kg |

Mass of proton | *m*_{p} | 1.67492 x 10^{-27} kg |

Permitivity of free space | epsilon-naught | 8.854 x 10^{-12} C^{2}/N m^{2} |

| *k* = 1/4 pi *e*_{0} | 8.987 x 10^{9} N m^{2}/C^{2} |

Permeability of free space | mu-naught | 4 pi x 10^{-7} Wb/A m |

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