A soap bubble is floating in the air. The refractive index ofthe bubble is n = 1.33. The width of the wall is 115 nm. The lightthat hits the bubble is reflected on the outer and inner surfaceand both interfere once they leave. The difference in phase forboth for both lights will be wt, where t is the time it takes forthe light to go and return through the soap layer (t = d / (c /n)).
a) Draw a picture showing how interference occurs when light isreflected from thin films.
b) The light that most reflects towards the front of the bubbleis that where the phase is 2pi. Find the formula for the frequencyof light that is most feflected from the front. (At other anglesthis changes, since d = t / cos (0)). What is this value for thebubble?
c) What happens in other angles? What do the colors of the lightreflected by the bubble look like?
