Hi, I am learning about refraction and the million ways in which Snell's Law is presented to me is making me confused... So, I understand that: sin i / sin r, will give me the ratio of speeds c_{i}/c_{r} and λ_{i}/λ_{r} However, I can't understand this form of: n_{1}sin i = n_{2} sin r How does it drop out? Thanks, Peter G.
Don't forget the meaning of the index of refraction: n = c/v (where c = speed of light in a vacuum and v = speed of light in the media) In your notation: c_{1} = c/n_{1} c_{2} = c/n_{2}