A grating made of 5550 slits/cm has red light of 0.680 m incident on it. The

Question:

A grating made of 5550 slits/cm has red light of 0.680 μ m incident on it. The light shines through the grating onto a screen that is 5.50 m away.
(a) What is the distance between adjacent slits on the grating?
(b) How far from the central bright spot is the first-order maximum on the screen?
(c) How far from the central bright spot is the second-order maximum on the screen?
(d) Can you assume in this problem that sin θ = tan θ? Why or why not?