A 1036 nm film with an index of refraction n=2.62 is placed on the surface of glass n=1.52. Light (λ=520.0 nm) falls hits the perpendicular to the surface from air. You want to increase the thickness so the reflected light cancels. What is the minimum thickness of the film that you must add?

You have two photos of a person walking. one shows the person at the corner of third and main streets, the other shows the person at the corner of tenth and main streets. there are lampposts at every corner in this town, and the first picture shows it to be 10: 32: 00 exactly. the second picture shows it to be 10: 49: 30. you know three facts: (1) all of the clocks are synchronized; (2) there are exactly 12 equal-sized blocks per kilometer in this town; and (3) the streets that cross main in this area are numbered consecutively, with no interruptions. what is the person’s average speed in kilometers per hour?