Diffraction from compact discA laser beam of wavelength 632 nm shines at normal incidence on the reflective side of a compact disc.

a) The tracks of tiny pits in which information is coded onto the CD are 1.60μm apart. For whatangles of reflection (measured from the normal) will the intensity of light be maximum?
b) On a DVD, the tracks are only 0.74μm apart. Repeat the calculation for that DVD.