What direction does light bend when it exits a glass block?

When light travels from a denser medium, like glass, to a less dense medium, such as air, it bends away from the normal. This is due to the change in speed of light as it passes from one medium to another. In glass, light travels slower than it does in air. When light exits the glass block, it speeds up as it transitions into the air, and this change causes the light rays to bend away from the line that is perpendicular to the surface of the glass (the normal line).

Understanding this behavior is essential in optics, as it explains phenomena like the formation of rainbows and the functioning of lenses. The bending of light at the interface of different media is an important principle that underlies many optical devices and natural optical effects.