How Fast does Light Travel Through Other Surfaces?
The speed of light is less than “c” or the defined constant that travels through a vacuum when it travels through air or other materials such as glass. The ratio between the vacuum speed or “c” and that which travels through the material “v” is called the refractive index “n” of the material. “N” is equal to c/v. An example of this is that the refractive measurement of glass is classically 1.5.
