Consider the interference pattern produced by two parallel slits of width a and separation d, in which d = 3a. The slits are illuminated by normally incident light of wavelength λ.
(a) First we ignore diffraction effects due to the slit width. At what angles θ from the central maximum will the next four maxima in the two-slit interference pattern occur?
(b) Now we include the effects of diffraction. If the intensity at θ = 0 is I0, what is the intensity at each of the angles in part (a)? (Use the following as necessary: I0.)
(c) Which double-slit interference maxima are missing in the pattern?
Only the third interference maximum is missing.
Every third interference maximum is missing.
None of the interference maxima are missing.