Question A6 It is desired to apply an anti-reflection coating on a glass lens used in air, by coating the lens with a thin film of magnesium fluoride of refractive index n = 1.37; (assume the glass has refractive index larger than nF). Write down the formula for optical path difference between waves reflected at top and bottom of the film, and use this to calculate the minimum required thickness of the coating to give a reflectance minimum for normal-incidence green light of wavelength 550 nm in air.

The nonreflective coating on a camera lens with an index of refraction of 1.31 is designed to minimize the reflection of 600-nm light. If the lens glass has an index of refraction of 1.55, what is the minimum thickness of the coating that will accomplish this task? m

answer for the second two

The following problem must be solved taking into consideration the modification given below: A student holds a laser that emits light of wavelength 545 nm. The laser beam passes though a pair of slits separated by 0.500 mm, in a glass plate attached to the front of the laser. The beam then falls perpendicularly on a screen, creating an interference pattern on it. The student begins to walk directly toward the screen at 2.00 m/s. The central maximum on the screen is stationary. Find the speed at which the 5th-order maxima changes its position on the screen. Do not use small angle approximation. Modification: Suppose there is a liquid in the space between the slits and the screen. Give such liquid any refractive index you desire (numerical value). Also suppose that the screen has a finite lenght (give another numerical value). Besides calculating the speed at which the 5th-order maxima changes its position on the screen also calculate the initial value of bright fringes according to the…