# Physical and Astronomical Constants to Remember for IAS

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Speed of light in vacuo | ||

Elementary charge | ||

Neutron rest mass | ||

Proton rest mass | ||

Electron rest mass | ||

Planck՚s constant | ||

Dirac՚s constant | ||

Boltzmann՚s constant | ||

Gravitational constant | ||

Stefan- Boltzmann constant | ||

First Radiation Constant | ||

Second Radiation Constant | ||

Permittivity of free space | ||

Permeability of free space | ||

Avogadro constant | ||

Gas constant | ||

Bohr radius | ||

Bohr magneton | ||

Fine structure constant | ||

Solar Mass | ||

Solar radius | ||

Solar luminosity | ||

Earth mass | ||

Mean earth radius | ||

1 light year | Mean earth radius | |

1 AU | Astronomical unit | |

1 pc | Parsec | |

1 year |

ENERGY CONVERSION: