The article discusses the definition of the second, a fundamental unit of time in the International System of Units (SI). The second is defined as the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the cesium-133 atom. This definition was adopted by the 13th General Conference on Weights and Measures (CGPM) in 1967.
The article also mentions that the CGPM has established general principles for writing unit symbols and listed some coherent derived units with special names. The 10th CGPM and subsequent compilations of base units have provided more recent advances in the definitions of the second.
However, the article lacks proper formatting and contains grammatical errors, making it difficult to understand the complete information about the definition of the second and its implications for the SI system.
Source: https://www.nist.gov/pml/special-publication-330/sp-330-appendix-4
Keywords: base, duration, second, unit, time
