A pair of slits, separated by 0.150 mm, is illuminated by light having a wavelength of ? = 631 nm. An interference pattern is observed on a screen 156 cm from the slits. Consider a point on the screen located at y = 1.50 cm from the central maximum of this pattern.
(a) What is the path difference d for the two slits at the location y?
(b) Express this path difference in terms of the wavelength.