The diagram shows light incident from above on a film of thickness d. Each of the three materials in the figure can be chosen to be air, with index of refraction n=1.00, water, with index n=1.33, or glass, with index n=1.50. Under which of the following conditions will the reflected light be completely or nearly eliminated by interference? (lambda2 refers to the wavelength of the light inside the thin film.) (Note: In the case that d<<lambda2, you can assume the thickness is so small that the travel distance in material 2 has negligible affect on the phase of the wave. Treat this as if the two interfaces are almost right on top of each other.) True or False:
a.) d=lambda2/2, material 1 is air, 2 is water, 3 is glass. b.) d<<lambda2, material 1 is water, 2 is glass, 3 is air. c.) d=lambda2/4, material 1 is air, 2 is water, 3 is glass. d.) d=lambda2/4, material 1 is air, 2 is glass, 3 is water. e.) d=lambda2/2, material 1 is glass, 2 is water, 3 is glass.
PART B:
f.) Determine the minimum thickness of a soap film (n= 1.30) that will result in constructive interference of a specific red line with wavelength 640 nm.