Light behaves in specific ways. It can be reflected, refracted, or absorbed, and under certain conditions, run into different kinds of interference. Which explanation best describes why light is refracted as it enters water?

A. The light bends when it enters water due to its reflection.

B. The speed of light remains the same as it moves from air to water, causing the light to reflect.

C. The speed of light increases when it enters a different medium, but it doesn't bend.

D. The speed of light changes as it moves from air to water, causing the light to bend.

Refraction is generally defined as the change in the direction of a wave as it travels from one medium to another. Light is a form of wave and light refraction is caused by a change in the speed of light as it moves from air to water, causing the light to bend in the process. The medium of travelling has to be transparent.

The change in the speed and direction is due to the variability in the refractive index of media. Light travels faster as it moves from a medium of higher refractive index to a medium of lower refractive index and vice versa.

The correct option is D.