A diffraction grating defines an optical component with a periodic structure that splits the light into various beams that travel in different directions. It is an alternative way to observe spectra other than a prism. Generally, when light is incident on the grating, the split light will have maxima at an angle θ. The formula for diffraction grating is used to calculate the angle.
Diffraction grating formula
Where,
- n is the order of grating,
- d is the distance between two fringes or spectra
- λ is the wavelength of light
- θ is the angle to maxima
Solved Examples
Question 1: A diffraction grating is of width 5 cm and produces a deviation of 300 in the second-order with the light of wavelength 580 nm. Find the slit spacing.
Solution:
Given: Angle θ =300, order n = 2, wavelength λ = 580 nm.
The slit spacing is given by,
d = 2×580×10-9 /sin
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