The dispersion of a diffraction grating, such as the one shown at the right, is the angle of separation per μm of wavelength, Î"Φ /Î"λ. It depends on the order of the diffraction (n), the distance between grooves (d) and the angle of the emerging light (Φ).
Calculate the dispersion at Φ = 11 ° of the first order diffraction for a grating with 8.0 Ã- 102 grooves per centimeter. Give the answer in °/μm.