Light is incident on a grating at an angle ψ as shown in Fig. 36-52. Show that bright fringes occur...

Light is incident on a grating at an angle ψ as shown in Fig. 36-52. Show that bright fringes occur at angles θ that satisfy the equation d (sin ψ +sin θ) = mλ, for m = 0, 1, 2,… (Compare this equation with Eq. 36-25.) Only the special case (ψ = 0 has been treated in this chapter.

Fig.36-52