An oil film floats on a water surface.The indices of refraction for water and oil,respectively,are 1.333 and 1.466.If a ray of light is incident on the air-to-oil surface at an angle of 42.3° with the normal,what is the angle of the refracted ray in the water?

Question

Quizplus · Accepted Answer

Using Snell's law:
n1sinθ1 = n2sinθ2
where n1 and θ1 are for air, n2 and θ2 are for oil.
sinθ2 = (n1/n2)sinθ1 = (1.333/1.466)sin42.3° = 0.8745
Now the ray moves from oil to water, so we use Snell's law again:
n2sinθ2 = n3sinθ3
where n3 and θ3 are for water.
sinθ3 = (n2/n3)sinθ2 = (1.466/1.333)(0.8745) = 0.9608
θ3 = sin⁻¹(0.9608) = 30.3°
Therefore, the angle of the refracted ray in water is 30.3°.

An Oil Film Floats on a Water Surface