posted by Steve .
Find the angle of refraction if there is one. If there isn't, tell which substance reflects the light:
I solved for all of the angles using Snell's law, but I don't know how to tell if there's no angle of refraction and which substance would reflect the light.
There is no refraction angle (A2) if the sine of the computed angle (using Snell's law) is equal to or greater than 1.
N1 sin A1 = N2 sin A2
sin A2 = (N1/N2) sin A2 < 1
sin A2 < N2/N1;
otherwise there is only total internal reflection