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spectrophotometer,instrument for measuring and comparing the intensities of common spectral lines in the spectra of two different sources of light. See photometryphotometry
, branch of physics dealing with the measurement of the intensity of a source of light, such as an electric lamp, and with the intensity of light such a source may cast on a surface area.
..... Click the link for more information. ; spectroscopespectroscope,
optical instrument for producing spectral lines and measuring their wavelengths and intensities, used in spectral analysis (see spectrum). When a material is heated to incandescence it emits light that is characteristic of the atomic makeup of the material.
..... Click the link for more information. ; spectrumspectrum,
arrangement or display of light or other form of radiation separated according to wavelength, frequency, energy, or some other property. Beams of charged particles can be separated into a spectrum according to mass in a mass spectrometer (see mass spectrograph).
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spectrophotometer(spek-troh-foh-tom -ĕ-ter) An instrument designed to measure the intensity of a particular spectral line or a series of spectral lines in an absorption or emission spectrum.
a spectroscopic instrument by means of which photometric measurements are carried out. In spectrophotometers, the light flux being measured is compared with a standard, or reference, flux for a continuous or discrete series of radiation wavelengths. The results of the comparison may be read manually or be recorded automatically on a chart where the abscissa is the wavelength and the ordinate is the result of the photometric measurement at this wavelength.
Also classed as spectrophotometers are analytical instruments that, instead of measuring spectra, determine the concentration of elements in a sample on the basis of the absorption or emission lines of atoms in a flame (absorption or flame spectrophotometers) or determine the concentration of components in mixtures of substances on the basis of characteristic absorption bands (double-beam infrared spectrophotometers or analyzing spectrophotometers).
The principal types of spectrophotometers are described in SPECTROSCOPIC INSTRUMENTS.