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Difference Between Continuous Spectrum and Line Spectrum

Main Difference

The main difference between Continuous Spectrum and Line Spectrum is that Continuous Spectrum is a spectrum that is formed with no separating lines and can be produced by superimposition of emission and absorption spectra of the same element, whereas Line Spectrum is a spectrum that contains either isolated emission lines or absorption lines with a huge gap between each other.

Continuous Spectrum vs. Line Spectrum

A Continuous Spectrum is a spectrum that is formed by the superimposition of emission and absorption spectra of the same element. Line Spectrum is a spectrum that is either isolated emission lines that have bright lines in the dark background in it or an absorption spectrum that has dark lines in a brighter background.

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As Continuous Spectrum is formed by the superimposed image of emission and absorption spectra, they contain no visible gaps in this spectrum. However, Line Spectrum contains huge gaps between lines. Continuous Spectrum contains all frequencies in equal intensity with no variation in it. In contrast, Line Spectrum contains a few frequencies, or it has frequencies of significantly varying intensity than other remaining ones.

Continuous Spectrum being a superimposed image of both emission and absorption spectrum contains wavelength of all ranges in it, but Line Spectrum being an alone spectrum, i.e., either absorption or emission spectrum contains only a few wavelengths. The common examples for Continuous Spectrum are black body radiation or Rainbow formation in the sunlight. And however, for the Line Spectrum, the common examples are emission or absorption spectra of hydrogen.

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Comparison Chart

Continuous SpectrumLine Spectrum
A spectrum that is formed by superimposition of emission and absorption spectra of the same element is called Continuous SpectrumA spectrum that is either isolated emission or an absorption spectrum is known as Line Spectrum
Gaps
Contain no visible gapsContain huge gaps between lines
Intensity
Contains all frequencies in equal intensityContains frequencies with significantly greater or lesser intensity than the remaining ones
Wavelength
Contains wavelength of all ranges in itContains only a few wavelengths
Examples
Rainbow and black body radiation etcExamples of Line Spectrum are the emission spectrum of hydrogen or the absorption spectrum of hydrogen etc

What is Continuous Spectrum?

Continuous Spectrum is formed by creating a superimposed image of both the emission spectrum, which has bright lines in the dark background in it and the absorption spectrum, which has dark lines in a brighter background. Continuous Spectrum requires that it should contain all wavelengths in a given range, or else it cannot be a continuous spectrum. As Continuous Spectrum is formed by the superimposed image of emission and absorption spectra, they contain no visible gaps in this spectrum. However, scientists believe that these types of spectrums also contain gaps, but they are not visible to the naked eye and can analyze with the help of a spectrometer.

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An Ideal spectrum does not contain any gaps between the spectrum, and this idealistic spectrum can be achieved only at laboratories under controlled situations. When a visible light ray diffracts, it produces a Continuous Spectrum that contains several colors with no visible lines in between each other.

However, these colors merge to form a similar intensity containing spectrum. That’s why Continuous Spectrum contains all frequencies with equal intensity and no variation in it, and as a superimposed image of both emission and absorption spectrum, it contains wavelength of all ranges in it.

The common examples for Continuous Spectrum are black body radiation or rainbow formation in the sunlight. In the rainbow formation, the white sunlight, when passing through the mist, it disperses the colors. For a naked eye range of these colors appear to be complete with equal intensity as each color blends in the next one very smoothly. This same process can be carried out in a laboratory when this light passed through a prism, which also disperses the light rays into these layers of beautiful colors.

What is Line Spectrum?

Line Spectrum formed as in either an absorption spectrum or an emission spectrum, and it shows separate absorption lines that appear as thick dark lines with a brighter background or bright emission lines that appear on a darker background.

Line Spectra also produced using the same source of light as was used in a Continuous Spectrum, but the continuous spectrum produced under high pressure. However, this same process carried out under lower pressure; it can give rise to emission spectrum or absorption spectrum.

The absorption spectrum is produced when radiation is passed through a specific material. The matter absorbs some of the rays with specific wavelengths; however, absorbed photons are not re-emitted in the same direction, rather due to the absence of absorbed electromagnetic radiation, darker lines appear in the spectrum.

This absorption spectrum is presented with absorbance on the y-axis with frequency or wavelength on the x-axis. These spectrums are used in various techniques as in atomic absorption spectroscopy and UV absorption spectroscopy to identify certain species in a given mixture or for confirmation of particular species.

Emission Spectrum formed in the same way when a beam of electromagnetic radiation hit with a sample of molecules or atoms; the electrons absorb energy and transfer themselves to a higher energy level. However, when they fall back to lower energy levels back after releasing the additional energy, they had absorbed to go up in the higher energy level. This released energy is plotted against the wavelength and called an emission spectrum.

Where darker lines denote an absorption spectrum, but the emission spectrum denoted on the opposite with brighter lines on a darker background. For a substance, the lines of absorption spectrum correspond to the frequencies of the emission lines. This is due to the energy absorbed by the electrons to reach a higher state and emission of these energies as when they returned to the lower energy level where it was residing at first.

Thus Line Spectrum contains huge gaps between lines and a few frequencies or frequencies of significantly varying intensity than other remaining ones. The common examples for the Line Spectrum are emission or absorption spectra of hydrogen. It also is seen when a pure element is heated; its rays, when passed through a prism has produced a spectrum consisting of a limited number of narrow lines with sizable gaps in between them.

Key Differences

  1. A Continuous Spectrum formed by superimposition of emission and absorption spectra of the same element, and on the contrary, Line Spectrum is a spectrum that is either emission spectrum or an absorption spectrum of the same element.
  2. Continuous Spectrum contains no visible gaps in its spectrum; on the flip side, Line Spectrum contains huge gaps between lines.
  3. Continuous Spectrum contains all frequencies with equal intensity, whereas Line Spectrum contains a few frequencies, or it has frequencies of significantly varying intensity than the rest of them.
  4. Continuous Spectrum contains wavelengths of all ranges in it; on the other hand, Line Spectrum being an alone spectrum, i.e., either absorption or emission spectrum contains only a few wavelengths.
  5. Continuous Spectrum is observed in black body radiation or rainbow formation in the sunlight; on the flip side, in the case of the Line Spectrum, the common examples are emission or absorption spectra of hydrogen.

Conclusion

The Continuous Spectrum contains no separating lines and is produced by superimposition of emission and absorption spectra of the same element, but Line Spectrum contains either isolated emission lines or absorption lines that have a huge gap in between them.

Harlon Moss

Harlon currently works as a quality moderator and content writer for Difference Wiki. He graduated from the University of California in 2010 with a degree in Computer Science. Follow him on Twitter @HarlonMoss