The SI unit is an international system of measurement used universally in technical and scientific research to avoid confusion with units. you can download the All **SI Units List** PDF below.

**UNIT:** The unit is the universal standard used for comparing any physical quantity, and it is called the unit of that physical quantity. For example, the unit of length is meter, the unit of time is second, and the unit of mass is kilogram.

* SI units are divided into two groups*……..

## Fundamental SI Units

There are seven types of fundamental SI units

Quantity | SI unit | Symbol |
---|---|---|

Length | meter | m |

Mass | kilogram | kg |

Time | second | s |

Electric current | ampere | A |

Temperature | kelvin | K |

Amount of substance | mole | mol |

Luminous intensity | candela | cd |

**1. Unit of length**: The unit of length in the SI unit system is the meter, denoted by ‘m’.

**2. Unit of mass**: The SI unit of mass is the kilogram, denoted by ‘kg’.

**3. Unit of time**: The SI unit of time is the second, denoted by ‘s’.

**4. Unit of temperature**: The SI unit of temperature is Kelvin, which is denoted by ‘K’.

Kelvin Temperature (K) = Celsius Temperature (C) + 273.5

Celsius temperature is used in daily life.

**5. Unit of the amount of substance:** The SI unit of the amount of a substance used in chemistry is the mole, denoted by mol. There are 6.02×10^23 (Avogadro’s number) atoms or ions in one mole.

**6. Unit of Electric current**: The SI unit of electric current is the ampere, denoted by A.

**7. Unit of luminous intensity**: The SI unit of luminous intensity is the candela, denoted by cd.

## Derived SI units

Derived SI units are unlimited, and they are all obtained with the help of basic quantities. These basic quantities are the original quantities, and any quantity that can be expressed in terms of them is called a Derived SI unit.

Quantity | SI unit | Symbol |
---|---|---|

Area | square meter | m² |

Volume | cubic meter | m³ |

Velocity | meter per second | m/s |

Acceleration | meter per second squared | m/s² |

Force | newton | N |

Energy | joule | J |

Power | watt | W |

Pressure | pascal | Pa |

Electric charge | coulomb | C |

Electric potential | volt | V |

Electric resistance | ohm | Ω |

Electric capacitance | farad | F |

Magnetic flux | weber | Wb |

Magnetic field strength | tesla | T |

Inductance | henry | H |

Frequency | hertz | Hz |

Angle | radian | rad |

Solid angle | steradian | sr |

Illuminance | lux | lx |

### System Of Units

**C.G.S (French system):** centimeter, gram, Second

**M.K.S (Metric system):** meter, kilogram, second

**F.P.S (British system):** foot, pound, second