1. The problem statement, all variables and given/known data The figure below shows the path of a beam of light through several layers (n1 = 1.58, n2 = 1.42, n3 = 1.20 and n4 = 1.00) of different indices of refraction. https://loncapa2.physics.sc.edu/res/brookscole/serway/College_Physics_7ed/Chap22/graphics/serw2244.gif a) If θ1 = 30.3 deg, what is the angle, θ2, of the emerging beam? (5.29×10^1 deg) b) What must the incident angle, θ1, be in order to have total internal reflection at the surface between the n3 = 1.20 medium and the n4 = 1.00 medium? 2. Relevant equations For part a) n1sin(theta1)=n2sin(alpha) n2sin(alpha)=n3sin(beta) n3sin(beta)=n4sin(theta2) For part b) I'm not too sure. 3. The attempt at a solution For part a) n1sin(theta1)=n2sin(alpha) (1.58)sin(30.3)=(1.42)sin(alpha) alpha=34.15099 n2sin(alpha)=n3sin(beta) (1.42)sin(34.15099)=(1.20)sin(beta) beta=41.628239 n3sin(beta)=n4sin(theta2) (1.20)sin(41.628)=(1)sin(theta2) theta2=52.90 deg ---> this is the correct answer (the formulas can also be simplified to... theta2=arcsin(n1sin(theta1)/n4) For part b) This is the part I"m having difficulties with. (1.20)sin(theta)=(1.00)sin(90) sin(theta)=(1.00)/(1.20) theta=56.44269 deg I know that this isn't the answer. Am I right in connecting the total internal reflection with sin(90)? Is the critical angle equivalent to the incident angle...are they the same thing?