Light refraction through fused quartz prism with 80° incident angle

[cmilho10]

Light of wavelength 700 nm is incident on the face of a fused quartz prism at an angle of 80.0° (with respect to the normal to the surface). The apex angle of the prism is 60.0°.

Use the value of n from Figure 35.20, to calculate the following angles.
(a) the angle of refraction at the first surface
(b) the angle of incidence at the second surface
(c) the angle of refraction at the second surface
(d) the angle between the incident and emerging rays

n=1.46

I used snell's law in order to find (a) which is 42 degrees, but when i try to do the geometry for the other parts it says my answers are wrong (i got 18 degrees for part b). It is hard to explain without drawing a picture exactly where i went wrong, but if anybody has any suggestions i would appreciate it.

 

[vanesch]

Light of wavelength 700 nm is incident on the face of a fused quartz prism at an angle of 80.0° (with respect to the normal to the surface). The apex angle of the prism is 60.0°.
Use the value of n from Figure 35.20, to calculate the following angles.
(a) the angle of refraction at the first surface
(b) the angle of incidence at the second surface
(c) the angle of refraction at the second surface
(d) the angle between the incident and emerging rays
n=1.46
I used snell's law in order to find (a) which is 42 degrees, but when i try to do the geometry for the other parts it says my answers are wrong (i got 18 degrees for part b).

I have to say I don't find any error. Using Snell's law you have indeed 42.4 degrees for (a), and if the apex angle is 60 degrees, this means that you have 17.6 degrees (60 - 42.4) on the other side for (b) wrt to the other normal...