There are two popular types of spectrum known today namely continuous spectrum vs. line spectrum. In physics, these terms are used to describe the display given when light is passed through a prism although this is not the only way spectra are formed. There are various differences between continuous and line spectrum, both which are part of the complete electromagnetic spectrum.
A continuous spectrum is produced when all the colors of a rainbow (from red to violet) are present. Essentially, light bends (refracts) when passed through a prism which is why we can see the rainbow after it as rained. White light is believed to contain all the seven rainbow colors which are absorbed at different wavelengths when refracted in a prism. If all the seven colors are present with no gaps between them, it makes a continuous spectrum. Line spectrum on the other hand only contains a few lines (wavelengths).
It is important to understand the whole context of electromagnetic spectra, absorption spectra and emission spectra. Atoms can absorb some wavelengths when subjected to electromagnetic radiation and present given absorption lines. They can also emit some of the wavelengths when they are excited; this is the energy lost for atoms to settle back to their normal state. Line spectrum can therefore be found in both absorption and emission spectra which are exact opposites of each other. When an absorption spectrum and emission spectrum are combined, you get a continuous spectrum with all the wavelengths.
Truly white light, like that emitted by some stars and moons is a perfect example of continuous spectrum. The sun’s light is also believed to produce continuous spectrum since we can see the rainbow. However, sunlight has a combination of other elements like helium and hydrogen as evident in the absorption gaps seen between the rainbow colors following critical observation through a spectrometer.
Main Differences Between Continuous Spectrum and Line Spectrum
- Spectrum Gaps
Continuous Spectrum: Continuous spectra contain no observable gaps.
Line Spectrum: There are huge gaps between lines.
- Wavelength of the spectra
Continuous Spectrum: Continous spectrum contains all the wavelengths of a given range.
Line Spectrum: Line spectrum contains only a few wavelengths.