Question

6.(10pts) The wings of some beetles have closely spaced parallel lines of melanin, causing the wing to act as a reflection diffraction grating. Suppose sunlight shines straight onto a beetle's wing. If the melanin lines on the wing are spaced 2.2 um apart, what is the first order diffraction angle for the green light (à - 550 nm)?

Answer 1

Answer 2

equation: dsinθ_m=mλ

d = 2.2*10^-6 m

m = 1 (order of diffraction)

λ = 550*10^-9 m

solving for θ

(2.2*10^-6)sin(θ_m)=1*(550*10^-9)

θ_m = 14.48 degrees