1. The problem statement, all variables and given/known data What is the maximum value of θ1 that would cause total internal reflection to occur? N1 = 1.3, n2 = 1.6 (picture attached) 2. Relevant equations Critical angle = sin^-1(n1/n2) 3. The attempt at a solution I figured the critical angle to be 54.3. That means that theta1 has to be less than 35.7 degrees in order for total internal reflection to occur, correct? However, the answer that I am supposed to get is 22.6 degrees. I am interested in seeing how this problem works out, but I'm also a bit shaky on the critical angle concept. Thanks for the help!