IEVref: | 112-02-08 | ID: | |

Language: | en | Status: Standard | |

Term: | kelvin | ||

Synonym1: | |||

Synonym2: | |||

Synonym3: | |||

Symbol: | K | ||

Definition: | SI unit of thermodynamic temperature, taking the fixed numerical value of the Boltzmann constant k to be 1,380 649 × 10^{−23} when expressed in the unit J/K, which is equal to kg m^{2} s^{−2} K^{−1}, where the kilogram, metre and second are defined in terms of h, c and ν_{Cs}
Note 1 to entry: The definition in the SI Brochure is: "The kelvin, symbol K, is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant Note 2 to entry: For 1 mol of an ideal gas, the internal energy is Note 3 to entry: The definition of the kelvin in IEV 112-02-08:2010-01 was: “SI unit of thermodynamic temperature, equal to the fraction 1/273,16 of the thermodynamic temperature of the triple point of water”. Note 4 to entry: The kelvin is one of the seven SI base units: second (s), metre (m), kilogram (kg), ampere (A), kelvin (K), mole (mol) and candela (cd). | ||

Publication date: | 2020-12 | ||

Source | SI Brochure, 9th edition, 2019, 2.3.1, modified – The definition in the SI brochure has been revised for conformity with the IEV rules. Notes 1 to 4 to entry have been added. | ||

Replaces: | 112-02-08:2010-01 | ||

Internal notes: | |||

CO remarks: | |||

TC/SC remarks: | |||

VT remarks: | |||

Domain1: | |||

Domain2: | |||

Domain3: | |||

Domain4: | |||

Domain5: |

Note 1 to entry: The definition in the SI Brochure is: "The kelvin, symbol K, is the SI unit of thermodynamic temperature. It is defined by taking the fixed numerical value of the Boltzmann constant *k* to be 1,380 649 × 10^{−23} when expressed in the unit J K^{−1}, which is equal to kg m^{2} s^{−2} K^{−1}, where the kilogram, metre and second are defined in terms of *h*, *c* and Δ*ν*_{Cs}."

Note 2 to entry: For 1 mol of an ideal gas, the internal energy is *U* = (3/2)*k**T**N*_{A}, where *k* is the Boltzmann constant, *T* is the thermodynamic temperature, and *N*_{A} is the Avogadro constant.

Note 3 to entry: The definition of the kelvin in IEV 112-02-08:2010-01 was: “SI unit of thermodynamic temperature, equal to the fraction 1/273,16 of the thermodynamic temperature of the triple point of water”.

Note 4 to entry: The kelvin is one of the seven SI base units: second (s), metre (m), kilogram (kg), ampere (A), kelvin (K), mole (mol) and candela (cd).