These dark lines indicate that the wavelengths have been absorbed by the medium through which the light has passed. In an absorption spectrum, portions of a continuous spectrum appear as dark lines or gaps. It is formed by electromagnetic radiation that has passed through a medium in which radiation of certain frequencies is absorbed. The key difference between continuous and line spectra is that the continuous spectrum contains all the wavelengths in a given range whereas the line spectrum contains only a few wavelengths. It is a characteristic property shown by molecules. In this type of spectra discontinuity or gaps appear between the bands or closely spaced bright lines. This spectrum is given by hot metals and molecular non-metals. The atomic spectrum of the elements is a “characteristic property” of the elements and is often termed as “fingerprints” of the elements. As electrons are part of the atom, Line spectra are also called atomic spectra Inert gases, metal vapors, and atomized non-metals form this kind of spectra. This is known as the line emission or discontinuous spectrum. These emitted wavelengths appear as sharp bright lines in the dark background forming a spectrum. Line Spectra or Atomic SpectraĪn electron in the excited state when makes the transition to lower energy states, the light of certain fixed wavelengths is emitted. Depending on the type of lines obtained, a discontinuous spectrum can be categorized into the following. (b) Discontinuous Spectrum: A discontinuous electromagnetic spectrum is the type that contains gaps, holes, or breaks in terms of the wavelengths that it contains. They emit radiation over a broad range of wavelengths thus the spectra appear smooth and continuous. Dense gases or solid objects when radiate heat, this spectrum is formed. (a) Continuous Spectrum (Thermal or Black body spectra): Remember, a rainbow is a continuous spectrum of the seven colours beautifully merging into one another. This line constitutes the emission spectrum. This means a spectral line of wavelength is emitted.
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