# *Physical constants

***Physical constants**

CONSTANT |
SYMBOL |
VALUE IN SI UNITS |
DIMENSIONS |

Absolute zero | K | -273.15 K | [K] |

Astronomical unit | AU | 1.5 x 10^{ 11} m |
[L ] |

Atomic mass unit or unified mass | u | 1.66 x 10^{ – 27} kg |
[M ] |

Avogadro’s constant | N_{0} |
6.023 x 10^{ 23} moleucles/mol |
[mol^{– 1}] |

Bohr magneton | m_{B} |
1.41 x 10^{ – 26 } J/T |
[AL^{2}] |

Bohr’s radius | b | 5.29 x 10^{ – 11 } m |
[L] |

Boltzmann’s constant | k | 1.38 x 10^{ – 23} J mol^{ – 1} K^{-1} |
[ML ^{2} T^{ – 2} K ^{– 1}] |

Coulomb’s constant | k | 9.00 x 10^{ 9} N m ^{2} C^{ – 2} |
[M^{1} A^{– } ^{2} L^{ 3} T^{ – 4}] |

Elementary charge | e | 1.6 x 10^{ – 19 } C |
[AT] |

Gravity | g | 9.8 ms ^{– 2} |
[LT^{ – 2}] |

Gravitational constant | G | 6.673 x 10^{ – 11} Nm^{ 2} kg^{ – 2} |
[M ^{– 1} L^{ 3} T^{ – 2}] |

Mass of earth | M | 5.98 x 10^{ 24 }kg |
[M ] |

Mass of electron at rest | m | 9.1 x 10^{ – 31} kg |
[M ] |

Mechanical heat equivalent | J | 4.186 J cal^{ – 1} |
no dimensions |

Molar volume of ideal gas at STP | V_{m} |
2.27 x 10 ^{– 2 } m^{ 3}/mol |
[L^{3 }mol ^{– 1}] |

Loschmidt constant | N_{0} |
2.69 x 10 ^{25} m^{ – 3} |
[L^{ – 3}] |

Permittivity constant | e_{0} |
8.85 x 10 ^{– 12 } F/m |
[M ^{– 1} A ^{2} L^{ – 3} T^{ 4}] |

Permeability constant | m_{0} |
1.26 x 10 ^{– 6 } H/m |
[M A^{– 2} L T^{ – 2}] |

Planck’s constant | H | 6.626 x 10^{ – 34} Js |
[ML^{ 2} T^{ – 1}] |

Radius of earth | R | 6.4 x 10^{ 8} m |
[L ] |

Rydberg constant | R | 1.10 x 10^{ – 7} m ^{– 1 } |
[L ^{– 1}] |

Specific charge of electron | e/m | 1.76 x 10^{ 11 } C/kg |
[ATL ^{– 1}] |

Speed of light in vacuum | c | 3.0 x 10^{ 8} m/s |
[L T^{ – 1}] |

Standard atmospheric pressure | 1 atm | 1.013 x 10^{ 5} Nm^{ – 2} |
[ML^{ – 1} T^{ – 2}] |

Solar constant | S | 1.4 x 10^{3} Wm ^{– 2} |
[MT^{ – 3}] |

Stefan – Boltzmann constant | s | 5.67 x 10^{ – 8} Wm^{ – 2} K^{ 4} |
[MT ^{– 2} K^{ – 4}] |

Triple point of water | T_{tr} |
273.16 K | [K] |

Universal gas constant | R | 8.31 J mol ^{– 1} K^{ – 1} |
[ML^{ 2} T^{ – 2} K^{ – 1}] |

Wien’s displacement constant | b | 2.89 x 10^{ – 3} mK |
[LK] |