Angle Calculation for Equilateral Prism

[shimizua]

Homework Statement

Light is incident on an equilateral crown glass prism at a thetain = 43.5o angle to one face, as seen in the figure below.
http://capa-new.colorado.edu/giancoli_lib/Graphics/Graph23/gian2351.gif
Calculate the angle (thetaout) at which light emerges from the opposite face. Assume that n = 1.52.

Homework Equations

ok so i did snells law and found it to be 26.94 deg.
so i know also that a triangle is 180 deg so i should just be able to subtract it all and get the answer

The Attempt at a Solution

well i subtracted it and got 109.56 deg and it was wrong

 

[Kurdt]

work out the angle that it strikes the other face first and then apply Snell's law again.

 

[shimizua]

i don't get what u mean by that?

 

[Kurdt]

The beam of light is refracted on the other surface of the prism, correct? What is the incident angle for that surface? Then you can work out the angle it leaves the prism.