Question

A diffraction grating is ruled at 1000 grooves/mm. What should be the size of the grating to resolve the spectrum content of an He-Ne laser (λ = 632.8 nm)? The frequency spectrum of the He-Ne laser consists of three narrow lines: one at 632.8 nm and two others are shifted by △υ = 450 MHz to both shorter and longer wavelengths. Would there be a better instrument to resolve this spectrum?

Answer 1

The questions can be solved using Resolving power of grating.

Firstly convert the .