Glossary term: Spectrum
Description: The variation in intensity of light from a source as a function of wavelength or frequency is called a spectrum. When the variation of light across wavelengths is relatively smooth, it is called a continuous spectrum. On the other hand, there could be sharp dips or peaks in the spectrum; these are called absorption and emission lines, respectively. These lines arise mainly due to transitions of electrons within atoms: either absorbing or emitting radiation. Stars usually show absorption lines in their optical spectra which are superposed on continuum emission. The lines give important clues about the chemical composition of stars. The analysis of spectra is known as spectroscopy; instruments that allow for the recording of spectra are called spectroscopes, spectrometers or spectrographs.Related Terms:
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Term and definition status: This term and its definition is still awaiting approval
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