The parallel light beam (λ = 450 nm) incident normally on the grating. The lens is located directly behind the grille and projects the spectrum onto the screen remote from it at 0.5 m. The distance between the diffraction spectrum the maxima of the first order is equal to 12 cm. To determine the grating constant d, the total number N of the maximum in the spectrum, the deviation angle φ rays corresponding to the last diffraction maxima.

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