<span>The ratio of the speed of light in a vacuum to the speed of light in the material it is passing through is the index of refraction of that material. (A)</span>
A number that represents how refractive a medium; a ratio of the speed of light in a vacuum to the spee of light in a medium (n=c/v). The larger the index of refraction, the slower light travels.
-the larger the index of refraction, the more refractive it is
-materials with a larger refractive index will bend light more
