Regarding "Total Internal Reflection" Hi, and thanks in advance for viewing this post. I'd like to type out the question first; Q: Consider the optical interface between crown glass and ethanol. a) Under what conditions would total internal reflection be possible at this interface? Illustrate your answer with a light-ray diagram. b) White light travels from crown glass into ethanol. If the angle of incidence in crown glass is 60.00 degrees (not sure how to insert degree sign), what is the angular spread between the red and violet parts of the visible spectrum in the ethanol? Illustrate your answer with a light-ray diagram. c) Light travels from ethanol into crown glass. What is the Brewster angle in this situation? Illustrate your answer with a light-ray diagram. What is the significance of this angle of incidence? Ok, so I have completed question a) and b). (Still working on c). Any correction/advice would be greatly appreciated! Thanks again! Answers: a) In order for the total internal reflection to occur, the light must enter from higher index of refraction to a lower index of refraction, which in this case, Crown glass --> Ethanol. In addition, the incident angle must be greater than the critical angle, which is 63 degrees. Calculation: Crown glass = 1.52 > Ethanol = 1.36 Sinθc = (1.36)(1.00) / 1.52 θc = 63 degrees. Diagram: http://img146.imageshack.us/img146/5690/spa0202ux3.th.jpg [Broken] b) Calculation θi = 60 degrees n1 = 1.520 (for red light in crown glass) n2 = 1.376 (for violet light in crown glass) nR = 1.36 = Ethanol For red light; (will omit calculation due to complication of work on this thread lol) sinθR = 75 degrees For violet light; sinθR = 88 degrees θdisplacement = θR(violet) - θR(red) Therefore, θdisplacement = 88 - 75 = 13 degrees. Diagram: http://img513.imageshack.us/img513/3772/spa0201aj8.th.jpg [Broken] I apologize for the work not being neat T_T I'm still working on the question C so i will add to the post when its complete hehe Thank you very much!! again!!!