-Thin Film Interference -Polarization. Physics Mrs. Coyle. Thin Film Interference. http://graphics.stanford.edu/courses/cs348b-competition/cs348b-08/finals/soap.png. Thin Film Interference. Thin Film Interference. http://laser.physics.sunysb.edu/~hilary/graphics/interference.gif.
Ray 1 travels into the film and back it travels 2t (twice the thickness of the film). The path difference between the rays when they come out of the film is 2t.
The reflected rays coming out of the film (5) and the rays that reflected on the film interface with the air(2), must have a path difference of an integer multiple of l/2.
This is because (2) flipped going from a less dense to a more dense medium.
Note: l is the wavelength in the film.
Path Difference= 2t =ml /2
so thickness, t= ml /4
Calculate the minimum thickness of a soap bubble that results in constructive interference when a light of wavelength 500nm shines on it.
Waves reflecting from two surfaces can interfere.
Here light is reflected at glass/air and air/glass interfaces (sandwiched).
The interference produces concentric rings of rainbow colors.