What is Refractive Index? Refractive index of air, glass and water.

Refractive Index:

When a ray of light passes from one medium to another, refraction occurs that is, the ray is bent at the interface. The refractive index is a measure of how greatly a substance slows the velocity of light.

Glass has higher refractive index

• Air: 1
• Water: 1.2
• Glass: 1.5

The direction and magnitude of bending is determined by the refractive indices of the two media forming the interface.

When light passes from air into glass, a medium with a greater refractive index, it is slowed and bent toward the normal, a line perpendicular to the surface