Final answer:
When light hits a more dense medium, it slows down and changes direction. When light hits a less dense medium, it speeds up and changes direction.
Step-by-step explanation:
When light hits a medium that is more dense, it tends to slow down and change direction. This is known as refraction. The bending of light occurs because the speed of light is different in different media. A common example is when light passes from air (less dense) into water (more dense), causing the light to bend towards the normal.
On the other hand, when light hits a medium that is less dense, it tends to speed up and change direction again. This is also a result of refraction. An example of this is when light passes from water (more dense) into air (less dense), causing the light to bend away from the normal.
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