I've asked this question about 4 times on yahoo but no one seems to have the brains to answer it! Looking at the diagram: Just trying to get a better understand of "λ = asin Ѳ" I've marked what I think is the wavelength...can someone please advise? as I'm trying to get a report done and I don't want to say the wrong thing! If that's not the wavelength..is it the green line? Thank you!