Example
The diagram shows the path of a ray of red light passing through a glass prism:
- Name the process happening to the ray at the point X.
- There is no light emerging from the prism at Y. Name the process happening to the light at Y.
- How does the speed of light change, if at all, as (a) it passes point Y and (b) as it passes point Z?
Answer
- The process happening to the ray at the point X is refraction.
- The process happening to the light at Y is total internal reflection.
- (a) The speed of light does not change when light is reflected so as it passes point Y the speed stays the same (b)The speed of light increases as it passes from a dense medium (glass) into a less dense medium (air) so, as light passes point Z, its speed increases.
A second ray of red light strikes the prism at the point P as shown below.
Continue the path of the second ray, incident at P, through and out of the glass prism.
Answer