Knowra2019 redefinition of SI base unitsLinked fromLinked fromThe 16 pages that link to 2019 redefinition of SI base units, each with the reason it gives.All 16Broader topic 5Related 11Molar massRelated: It fixed the Avogadro constant and thereby gave the mole an exact particle count.KilogramRelated: It replaced the prototype-based kilogram definition with one based on the Planck constant.MoleRelated: It replaced the mole's carbon-12-based definition with an exact Avogadro constant.Vacuum permittivityRelated: It ended ε₀’s exact-value status by fixing the elementary charge instead.Unit of measurementRelated: It replaced several artifact-based definitions with standards grounded in constants of nature.AmpereRelated: It replaced the ampere's force-based definition with one based on elementary charge.Reduced Planck constantRelated: The redefinition fixed Planck’s constant exactly, thereby fixing ℏ in SI units.Faraday constantRelated: Fixing the elementary charge and Avogadro constant makes the Faraday constant exact in SI.International Prototype of the KilogramRelated: It replaced the prototype’s role with a definition anchored to the Planck constant.Physical constantRelated: It changed constants such as Planck's constant from measured quantities into anchors of unit definitions.Ampère's force lawRelated: It replaced the force-based definition of the ampere with a fixed value for the elementary charge.