http://www.ck12.org Chapter 13. Light
13.3 Refraction of Light
- Define refraction.
- Given data about the optical density of the media, predict whether the light will bend toward the normal or
away from the normal. - State Snell’s Law and solve refraction problems using it.
- Solve problems using the relationship between the index of refraction and the velocity of light in the media.
- Explain effects caused by the refraction of light.
When a light ray passes at an angle through the boundary between optically different media, the light does not travel
in a straight line. The pencil in the glass of liquid shown above is a normal straight pencil. The light that travels
from the pencil through the liquid, through the glass, and into the air is bent differently than light from the portion
of the pencil that is not in the liquid. Your eye assumes the light from both portions of the pencil moved in a straight
line, but the two portions of the pencil do not appear to be lined up. Your eye thinks the pencil is broken.
Refraction of Light
The speed of light is different in different media. If the speed of light is slower in a particular medium, that medium
is said to be moreoptically dense. When a wave front enters a new medium at an angle, it will change directions. If
the light is entering a more optically dense medium, the light bends toward the normal line. If the light is entering