## How does refraction of light affect the direction of light?

NOTIFICATIONS. Refraction of light in water. When light travels from air into water, it slows down, causing it to change direction slightly. This change of direction is called refraction. When light enters a more dense substance (higher refractive index), it ‘bends’ more towards the normal line.

### When does a light wave change speed and not refract?

The only time that a wave can be transmitted across a boundary, change its speed, and still not refract is when the light wave approaches the boundary in a direction that is perpendicular to it. As long as the light wave changes speed and approaches the boundary at an angle, refraction is observed.

Why is the angle of refraction lower in the second medium?

Since the phase velocity is lower in the second medium (v 2 < v 1 ), the angle of refraction θ 2 is less than the angle of incidence θ 1; that is, the ray in the higher-index medium is closer to the normal. Optical prisms and lenses use refraction to redirect light, as does the human eye.

How does refraction work in a glass block?

At the boundary between two transparent substances: the light slows down going into a denser substance, and the ray bends towards the normal the light speeds up going into a less dense substance, and the ray bends away from the normal The diagram shows how this works for light passing into, and then out of, a glass block.

NOTIFICATIONS. Refraction of light in water. When light travels from air into water, it slows down, causing it to change direction slightly. This change of direction is called refraction. When light enters a more dense substance (higher refractive index), it ‘bends’ more towards the normal line.

## What happens to the direction of light when it enters a substance?

This change of direction is called refraction. When light enters a more dense substance (higher refractive index), it ‘bends’ more towards the normal line. Refraction is the bending of light (it also happens with sound, water and other waves) as it passes from one transparent substance into another.

At the boundary between two transparent substances: the light slows down going into a denser substance, and the ray bends towards the normal the light speeds up going into a less dense substance, and the ray bends away from the normal The diagram shows how this works for light passing into, and then out of, a glass block.

### Why does a ray of light bend one direction?

The tendency of a ray of light to bend one direction or another is dependent upon whether the light wave speeds up or slows down upon crossing the boundary. The speed of a light wave is dependent upon the optical density of the material through which it moves.