Angstrom
Angstrom (ñngström, symbol: Å) is a unit of length. It is used to represent a very small length such as the wavelength of atoms, molecules, visible light. 1 Å is defined as 10 - 10 m = 0.1 nanometer = 100 picometers. Since the size of atoms and molecules and the wavelength of visible light are on the order of several thousand angstroms, they are numerically convenient in spectroscopy, etc., and once widely used. However, neither the International Ordinance Weights Committee nor the International Conference on Weights and Measures officially admit the use of this unit. In an international unit system based on one physical quantity unit as a rule it is treated as "other non SI unit" and when using it it is said that "definition of unit to be used must be given in SI units" (refer to SI combined unit ). ...