Chapter 37, Problem 23P

You are working as a demonstration assistant for a physics professor. For an upcoming lecture on diffraction gratings, he wishes to perform a demonstration where he shines a laser pointer at normal incidence onto the recorded surface of a DVD that is laying flat on the demonstration table. (a) He asks you to determine how many additional maxima beyond the normal reflection (which will be blocked by his hand holding the laser pointer) will be projected onto the ceiling or walls of the room if he uses a laser pointer with a wavelength of 632.8 nm. (b) He also asks you if he can show more maxima by using a laser pointer of another visible color. The tracks of pits on a DVD are separated by 0.800 μm.