Chapter 22, Problem 26P

* A laser beam is incident at $30°$ with respect to the normal on a stack of five transparent plates made of materials with the following indexes of refraction (from the top of the stack to the bottom): $n_1=1.20,n{-}_2=1.30,n_3=1.40,n_4=1.50,n_5=1.60$. The plates touch each other. Determine the angle between the outgoing beam and the normal to the last plate Assume the first and the last plate are in contact with air (Hint: Before you start calculating, write the expression for the final angle and see if you can simplify it.)