Answer:
Refraction
Explanation:
Refraction is a phenomenon typical of light waves. It occurs when a ray of light passes through the interface between two mediums: when doing so, the ray of light changes speed and also changes direction, according to Snell's Law:
[tex]n_1 sin \theta_1 = n_2 sin \theta_2[/tex]
where
[tex]n_1, n_2[/tex] are the index of refraction of the first and second medium, respectively
[tex]\theta_1, \theta_2[/tex] are the angle of incidence and refraction, respectively
When white light enters a prism, therefore, it undergoes refraction, and it changes direction.
However, the index of refraction of a material, n, depends also on the wavelength of the light. In particular, the shorter the wavelength, the higher the index of refraction.
This means that as white light enters a prism, the different wavelengths contained in the white light are refracted at different angles: as a result, the 7 colors of light will separate, and that is why we observe the rainbow when white light enters a prism.