Red light (n = 1.520) and violet light (n = 1.538) traveling in air are incident on a slab of crown glass. Both colors enter the glass at the same angle of refraction. The red light has an angle of incidence of 26.50°. What is the angle of incidence of the violet light?

Answer 1

Apparently the two colors enter the glass at different incidence angles but have the same angle of refraction (A) inside the glass.
For the red light,
sin 26.5 = 1.520 sinA
Therefore
sin A = 0.2936
A = 17.07 degrees

For the violet light, with the same angle of refraction A
sin I = 1.538 sinA = 0.4516
I = 26.84 degrees