A light ray is incident from air onto a glass surface with an index of refraction n = 1.56. Find the angle of incidence for which the corresponding angle of refraction is one-half the angle of incidence. Both angles are defined with the normal to the surface.
n = sin a1/sin a2 (Snell's Law)
sin(a + b) = (sin a x cos b) + (cos a x sinb)
sin(2a) = 2 sin a cos a
The Attempt at a Solution
Somehow you plug in the double angle formula into snells law. but I don't understand how this is a down. a breakdown of the equations used to solve problem would be extremely helpful :)