1. Refraction of Light Optical density a property of a transparent material that is an inverse measure of the speed of light through a material Optical refraction the bending of light rays as they pass obliquely from one medium into another of a different optical density Angle of refraction angle between refracted ray and normal

2. Index of Refraction, n the ratio of the speed of light in a vacuum to the speed of light in a given material n (for a given material) = c / speed of light in material Snell’s Law general: n 1 sin θ 1 = n 2 sin θ 2 special case: n = sin i / sin r i = angle of incidence in air r = angle of refraction in material

3. Laws of Refraction 1. The incident ray, refracted ray, and normal to the boundary at the point of incidence are all in the same plane. 2. The index of refraction for a homogeneous medium is a constant that is independent of the angle of incidence. 3. When a ray of light passes obliquely from a medium of lower optical density to one of higher optical density, it is bent toward the normal. (and vise versa)

4. When going from a more to less optically dense medium AND as you increase the angle of incidence, what happens to the angle of refraction? Critical Angle, i c is the limiting angle of incidence on the optically denser medium that results in an angle of refraction equal to 90°. sin i c = 1 / n Beyond i c, total internal reflection results