Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Critical Angle

  1. May 1, 2012 #1
    Snell's Law of Angles says that : sinA/sinB = nB/nA

    but in order to find critical angles B has to be 90° . I understand that in order to have total internal reflection that nB/nA < 1 but why can't there be a CRITICAL angle when nB/nA > 1 ?

    sinA would have to be greater than 1 which cannot happen but if i do it separately : glass to air and water to air and say that air-n-water = nwater/nair it is 1.33/1.5 which is true but if i do it in one go it is 1.5 / 1.33 . I must be doing something wrong , because this seems too easy :S
  2. jcsd
  3. May 1, 2012 #2


    User Avatar

    Staff: Mentor

    What do you mean by "if i do it in one go"?
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook

Similar Discussions: Critical Angle
  1. Critical angle (Replies: 1)

  2. Critical Angle Lab (Replies: 2)