Base quantities are simply the physical properties that are measured by each of the base SI Units.

All of the other SI units are derived from the base units. This means that all of the other SI units are basically different combinations of base units which have been given their own special names and symbols.

e.g Pressure is measured in units called Pascals and has the symbol Pa. However a Pascal is equivalent to a particular combination of base units. i.e. 1Pa = 1 kg/m.s

Physical quantity |
Name of unit |
Symbol |
Expressed in base units |
---|---|---|---|

Frequency | Hertz | Hz | 1/s |

Force | Newton | N | m.kg/s^{2} |

Work (Energy) | Joule | J | m^{2}.kg/s^{2} |

Pressure | Pascal | Pa | kg/m.s^{2} |

Power | Watt | W | m^{2}.kg/s^{3} |

Electric charge | Coulomb | C | A.s |

Electric potential | Volt | V | m^{2}.kg/s^{3}.A |

Electric capacitance | Farad | F | s^{2}.s^{2}.A^{2}/m^{2}.kg |

Electric resistance, reactance | Ohm | Ω | m^{2}.kg/s^{3}.A^{2} |

Electric conductance | Siemens | S | s^{3}.A^{2}/m^{2}.kg |

Magnetic flux | Weber | Wb | m^{2}.kg/s^{2}.A |

Magnetic induction | Tesla | T | kg/s^{2}.A |

Inductance | Henry | H | m^{2}.kg/s^{2}.A^{2} |

Luminous flux | Lumen | lm | cd.sr |

Illuminance | lux | lx | cd.sr/m^{2} |

Derived quantities are simply the physical properties that are measured by each of the units in the table above