The distance between the ruled lines on a grating is 1900 nm.The grating is illuminated at normal incidence with a parallel beam of white light in the 400 nm to 700 nm wavelength band.What is the angular width of the gap between the first order spectrum and the second order spectrum?

Question

Quizplus · Accepted Answer

The angular width of the gap between the first and second order spectra is determined by the difference in angles for the longest wavelength of the first order and the shortest wavelength of the second order. Using the grating equation d*sin(θ) = m*λ, for m=1 and m=2, the difference in angles is calculated to be approximately 3.3°.

The Distance Between the Ruled Lines on a Grating Is