20.5. Summary http://www.ck12.org
media.
n 1 sinθ 1 =n 2 sinθ 2
The index of refractionn 1 is the medium from which light originates andn 2 is the index of refraction of the medium
to which light passes. Angleθ 1 is measured with respect to the normal at the interface of medium 1 and angleθ 2 is
measured with respect to the (same) normal at the interface of medium 2. Snell’s law can be expressed in terms of
the velocities of light in the respective media as
v 2 sinθ 1 =v 1 sinθ 2
wherev 1 is the speed of the light in medium 1 andv 2 is the speed of light in medium 2.