In the double-slit experiment of Figure the viewing screen is at distance D = 4.00 m, point P lies at distance y = 20.5 cm from the center of the pattern, the slit separation d is 4.50μm, and the wavelength λ is 580 nm.
(a) Determine where point P is in the interference pattern by giving the maximum or minimum on which it lies, or the maximum and minimum between which it lies.
(b) What is the ratio of the intensity Ip at point P to the intensity Icen at the center of the pattern?