What is the difference between reflection and refraction?

The distinction between reflection and refraction is based on how light behaves when it encounters different surfaces or mediums.

Reflection involves light bouncing off a surface. When light strikes a reflective surface, such as a mirror or calm water, it returns into the original medium at an angle equal to the angle it arrived at, adhering to the law of reflection. This principle is evident in the clear images formed by mirrors and the shimmering surface of still water.

Refraction, on the other hand, occurs when light travels from one medium to another, such as from air to glass or from air to water, and experiences a change in speed. This speed change causes the light to bend at the interface of the two mediums. A common illustration of refraction is seen when a straw appears bent in a glass of water; this bending occurs due to the different speeds of light in water compared to air.

Therefore, the correct choice accurately captures these fundamental definitions by stating that reflection is the bouncing back of light, while refraction describes the bending of light as it transitions between different mediums. Understanding these concepts is crucial in optics, as they explain many optical phenomena we observe in everyday life.