Angstrom
From Encyclopædia
{ang'-struhm} The angstrom is a unit of length used principally for expressing the wavelengths of
radiation in the optical range. It is also used for smaller distances, such as those involving
atoms and
molecules. The unit was named for Anders Jonas ANGSTROM of Sweden, who in 1868 first attempted to measure the wavelengths of
light in metric units.One angstrom unit is equal to one ten-billionth meter, approximately the diameter of a hydrogen
atom. Visible
light is
radiation that has wavelengths within the range of about 4000 to 7000 angstroms. Current terminology favors the use of the nanometer (nm) instead of the angstrom. One nanometer equals (10 to the power of- 9) meter, or 10 angstroms.
