second, \(\text{s}\)

https://doi.org/10.1351/goldbook.S05513
The second, symbol \(\text{s}\), is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency \(\Delta\nu_\text{Cs}\), the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be \(9\ 192\ 631\ 770\) when expressed in the unit Hz, which is equal to \(\text{s}^{-1}\).
Source:
BIPM, The International System of Units, SI Brochure, 9th ed. (2019), p. 130 [Terms] [Book]
Citation: 'second' in IUPAC Compendium of Chemical Terminology, 3rd ed. International Union of Pure and Applied Chemistry; 2006. Online version 3.0.1, 2019. https://doi.org/10.1351/goldbook.S05513 RIS BibTex EndNote
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Last revised: January 1, 2021