Femto-
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This article is about the SI prefix. For the manga character, see Griffith (Berserk).
Femto- (symbol f) is a unit prefix in the metric system denoting a factor of 10−15 or 0.000000000000001. Adopted by the 11th General Conference on Weights and Measures,[1] it was added in 1964 to the SI.[2] It is derived from the Danish word femten, meaning "fifteen".
Examples of use:
- The HIV-1 virus weighs about 1 x 10−15 g or 1 fg. Orders of magnitude (mass)
- a proton has a diameter of about 1.6 to 1.7 femtometres.
- More examples available.
The femtometre shares the unit symbol (fm) with the older non-SI unit fermi, to which it is equivalent. The fermi, named in honour of Enrico Fermi, is often encountered in nuclear physics.
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- ^ The metric system was introduced in 1795 with several metric prefixes, of which, however, only six were adopted as SI prefixes by the 11th CGPM conference in 1960, whereas myria (104) as well as double and demi were not adopted. In 1873, micro and mega were recommended by the British Association for the Advancement of Science. The other dates relate to recognition by a resolution of the CGPM.
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