4. Light of a certain wavelength will reflect off of the top (1) and bottom (2) surfaces of a butterfly scale to constructively interfere. However, light can also reflect off the top surface of the next consecutive scale (3), and cause constructive interference for other wavelengths of light (this is why butterfly scales seem to made up of a mixture of many different colors). In the diagram to the right all these paths are straight up and down. The index of refraction of the butterfly scale is 1.6. Between which of the following two paths will the constant phase difference, Ao, be n radians? eye 1 2 3 n=1.0 n=1.6 130nm n=1.0 200nm a. Between paths (1) and (2). b. Between paths (2) and (3). c. Between paths (1) and (3). d. All of the above path differences lead to a t phase shift. e. Only choices a) and b) above will lead to a t phase shift.

4. Light of a certain wavelength will reflect off of the top (1) and bottom (2) surfaces of a butterfly scale to constructively interfere. However, light can also reflect off the top surface of the next consecutive scale (3), and cause constructive interference for other wavelengths of light (this is why butterfly scales seem to made up of a mixture of many different colors). In the diagram to the right all these paths are straight up and down. The index of refraction of the butterfly scale is 1.6. Between which of the following two paths will the constant phase difference, Ao, be n radians? eye 1 2 3 n=1.0 n=1.6 130nm n=1.0 200nm a. Between paths (1) and (2). b. Between paths (2) and (3). c. Between paths (1) and (3). d. All of the above path differences lead to a t phase shift. e. Only choices a) and b) above will lead to a t phase shift.