Refraction is the bending of light as it passes from one medium to another. Refraction is an effect that occurs when a light wave, incident at an angle away from the normal, Light is refracted when it crosses the interface from air into the glass in which it moves more slowly. Since the light speed changes at the interface. When light strikes at an angle, transmitted light changes direction if the index of refraction of the two media is different. This is called refraction.
