When a ray of light passes from one medium to another, its speed changes. This change in speed causes the ray to bend, or refract. However, there are some properties of the ray that do not change when it passes from one medium to another. These properties are:

- Frequency

- Wavelength

- Color

The frequency of a ray of light is the number of waves that pass a given point in one second. The wavelength of a ray of light is the distance between two adjacent peaks of the wave. The color of a ray of light is determined by its frequency.

When a ray of light passes from one medium to another, its speed changes, but its frequency, wavelength, and color do not. This means that the ray of light will still have the same color and will appear to have the same wavelength, even though it is traveling at a different speed.