A coin at the bottom of a bowl seems to rise when you pour in water. A pencil in a glass looks bent. In this course we find out why light bends when it goes from one material to another. We learn the laws of refraction and the refractive index, and we follow a ray through a glass slab.
3 lessons, about 1 h 30 min4 simulations14 problems6 practice questionsPython in every lesson
Created by StemPy LabRefraction is the bending of light when it goes from one transparent material to another. A ray bends toward the normal when it enters a denser material, and away from the normal when it enters a rarer one. The incident ray, the refracted ray and the normal lie in one plane, and is a constant for a pair of materials.
The absolute refractive index of a material is , the speed of light in a vacuum divided by its speed in the material. A larger index means slower light and more bending. The refractive index of one material with respect to another is the ratio of their absolute indices.
A ray that goes through a rectangular glass slab comes out parallel to the incident ray, but shifted sideways by the lateral displacement. The two bends at the two faces are equal and opposite. Refraction also makes a pool or a coin in water seem shallower than it is.
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