UV-visible spectrometers can be used to measure the
absorbance of ultra violet or visible light by a sample,
either at a single wavelength or perform a scan over a
range in the spectrum. The UV region ranges from 190
to 400 nm and the visible region from 400 to 800 nm.
The technique can be used both quantitatively and
qualitatively. A schematic diagram of a UV-visible
spectrometer is shown above.