Solution to task 518 from Chertov´s for extramural stud

Solution to task 518 from Chertov´s for extramural stud

518. Normally monochromatic light (λ = 410 nm) falls on the diffraction grating. The angle Δφ between the directions to the maxima of the first and second orders is 2 ° 21 ´. Determine the number n of grooves per 1 mm of the diffraction grating.