Anthony shines a beam of light on the surface of a solution of glycerol at a certain angle. If the angle of refraction is 38°, what is the angle of incidence? The index of refraction of glycerol is 1.47, while that of air is 1.00.

We can apply snell's law in this problem to determine the angle of incidence given the angle of refraction and different indices of refraction. In this case, snell's law is expressed as n1 sine theta1 = n2 sine theta2

substituting,

1 * sin 30 = 1.47 sin theta

theta can be determined easily then