What happens when light moves from glass to air?

When light moves from a denser medium, like glass, to a less dense medium, such as air, it undergoes a process known as refraction. In this case, as light exits the glass, it speeds up because the optical density of air is lower compared to glass.

As it speeds up, the direction of the light beam also changes. Specifically, it bends away from the normal line, which is the imaginary line perpendicular to the surface at the point of entry. This phenomenon occurs due to the change in speed of light in different media, governed by Snell's Law.

Therefore, the light transitions from a slower speed in glass to a faster speed in air, resulting in it bending away from the normal line.