Measuring wavelengths with a CD, A LASER beam of wavelength λ = 632.8nm shines at normal incidence on the refl?

Measuring wavelengths with a CD, A LASER beam of wavelength λ = 632.8nm shines at normal incidence on the reflective side of a compact disc. The track of tiny pits in which information is coded onto the CD are 1.60μm apart. For what angles of reflection (measured fro m normal) will the intensity of light be maximum?