International System of Units
The General Conference on Weights and Measures (CGPM) was formed by diplomatic accord and subsequently formulated the Treaty of the Meter. Originally, 17 nations (the United States inclusive) signed the agreement in Paris on May 20, 1875 with 48 nations currently designated as members.
The International System of Units – SI (derived from: Systeme International d’Unites) is administered by the International Bureau of Weights and Measures and periodically convenes its General Conference on Weights and Measures to evaluate measurement requirements.
The SI were formally adopted by CGPM in 1960. They consist of seven base units which, by convention are without reference to any other unit(s), and therefore regarded as independent. There are 22 other derived units which are formed according to various combinations with the base units.
|Seven SI Base Units|
|amount of substance||mole||mol|
|Sampling of Laser Photonics Derived Quantities|
SI Base Units
|plane angle||radian||rad||m·m-1 = 1|
|solid angle||steradian||sr||m2·m-2 = 1|
|energy, work, |
quantity of heat
|SI Prefixes & Symbols
Denoting Powers of 10
|micro||10-6||mu or µ|