A plastic film with index of refraction 1.89 is put on the surface of a car window to increasethe reflectivity and thus to keep the interior of the car cooler.The window glass has index of refraction 1.54.
a) What minimum thickness is required if light withwavelength 550 nm in air reflected fromthe two sides of the film is to interfere constructively?
b) It is found to be difficult to manufacture and install coatingsas thin as calculated in part (a) What is the next greatestthickness for which there will also be constructiveinterference?