How Does Light Emerge from a Prism Using Snell's Law?

[PeachBanana]

Homework Statement

Light is incident on an equilateral glass prism at a 45.0 °angle to one face. Calculate the angle at which light emerges from the opposite face. Assume that n = 1.49.
θ4 = ?

Homework Equations

n1 * sin θ1 = n2 * sin θ2

The Attempt at a Solution

n1 = 1.00 (air)
n2 = 1.49
sin 45° = 0.707

n1 * sinθ1 / 1.49 = sin θ2

sin θ 2 = 0.474
θ2 = 28.33°

I'm having trouble finding θ3.

n2 = 1.49
θ2 = 28.33°
n3 = 1.49
θ3 = ??

 

[grzz]

I suggest that you draw a diagram. Then knowing the angle you just found, you can calculate the angle at which the light is incident from glass to air at the second face of the prism.
Then use the same method as before.