The key difference between prism spectra and grating spectra is that in prism spectra, the spectrum is created due to the dispersion of light, whereas in grating spectra, the spectrum is created due to the diffraction of light.
A spectrum is a band or series of colours created by the separation of components of light according to the different degrees of refraction and their wavelengths. Prism spectra and grating spectra are two different types of spectra that differ from each other, mainly in the way of formation.
CONTENTS
1. Overview and Key Difference
2. What is Prism Spectra
3. What is Grating Spectra
4. Side by Side Comparison – Prism Spectra vs Grating Spectra in Tabular Form
5. Summary
What is Prism Spectra?
Prism spectra are the continuous spectra we can get using a prism. A prism is a transparent instrument that is triangular and has a refracting medium that can cause the refraction of light. It has a base and an apex, and its apical angle tends to determine the diprotic power of the material. When light passes through a prism, the light gets dispersed by it, giving a prism spectrum.
Visible light is usually white light, which contains a collection of component colours. Often, we can observe these colours when the light passes through a triangular prism. This is because the white light separates into its component colours when the light passes through the prism. The colour components that we can observe are red, orange, yellow, green, blue, and violet. Typically, this colour separation process is known as dispersion.
The dispersion of colours in light can be described based on the varying frequencies and wavelengths of each colour component. These different frequencies of light tend to bend in varying amounts as the light passes through the prism.
When considering the material of the prism, different materials have different optical densities (the optical density is the tendency of a material to slow down the light when the light passes through that material). When light is passing through a transparent material, it tends to interact with the atoms of the material. If the frequency of the light wave matches the resonance frequency of the electrons in atoms, the light is absorbed by that atom. The unabsorbed light comes out of the prism, which gives us the prism spectrum.
What is Grating Spectra?
Grating spectra is the spectra we can obtain from grating prisms. These spectra appear as line spectra, and they form due to the diffraction of light. This technique is very important in analyzing light sources. A grating spectrum contains a large number of equally spaced parallel slits. The basic phenomenon of the working principle of the grating spectra is light diffraction. There are spaces between lines of this spectrum that appears as slits; these slits diffract the light waves, producing many different beams that can interfere to produce a spectrum.
What is the Difference Between Prism Spectra and Grating Spectra?
Prism spectra and grating spectra are two different types of spectra that differ from each other, mainly in the way of formation. The key difference between prism spectra and grating spectra is that, in prism spectra, the spectrum is created due to the dispersion of light, whereas in grating spectra, the spectrum is created due to the diffraction of light. Moreover, prism spectra give a continuous spectrum, whereas grating spectra give a line spectrum.
The below infographic summarizes the differences between prism spectra and grating spectra in tabular form.
Summary – Prism Spectra vs Grating Spectra
Prism spectra and grating spectra are two different types of spectra that differ from each other, mainly in the way of formation. The key difference between prism spectra and grating spectra is that, in prism spectra, the spectrum is created due to the dispersion of light, whereas in grating spectra, the spectrum is created due to the diffraction of light.
Reference:
1. “Grating Spectrum.” An Overview | ScienceDirect Topics, Available here.
Image Courtesy:
1. “6174502” (CC0) via Pixabay
2. “Comparison refraction diffraction spectra” By Cmglee – Own work (CC BY-SA 3.0) via Commons Wikimedia