A triple-slit experiment consists of three narrow slits, equally spaced by distance d and illuminated by light of wavelength l. Each slit alone produces intensity I₁ on the viewing screen at distance L.
a. Consider a point on the distant viewing screen such that the path-length difference between any two adjacent slits is l. What is the intensity at this point?
b. What is the intensity at a point where the path-length difference between any two adjacent slits is λ/2?