index of refraction

The index of refraction measures how much a material slows down light compared to its speed in a vacuum. For example, in glass, light travels slower than in air, so glass has a higher index of refraction. This value helps explain phenomena like bending of light when it passes between different materials. A higher index means more bending and slowing of light. It's an important concept for designing lenses, optical devices, and understanding how light interacts with surfaces in everyday life.