a) In double-slit interference experiment, path difference Δ = dsin θ. Use ray diagram and words to explain why bright spotslocated at where Δ = mλ and dark spots located at where Δ=(m+1/2)λ.Here m = 0, ±1, ±2, ±3, etc.
b)Use any resource you can find to study the single-slitdiffraction. Explain how the diffraction pattern formed by laserlight passing a single narrow slit with width w. Explainwhere the dark spots would located. (You should find the equationfor this.) Use diagram(s) and words to explain why.
c) Explain what Babinet's principle is. Explain how you canmeasure the thickness of a hair using the principle ofdiffraction.
