When light passes through a medium, such as a transparent substance like glass or water, its speed and wavelength can be altered. This phenomenon is known as the refraction of light.
Speed of Light: The speed of light in a vacuum is constant and denoted as "c," which is approximately 299,792 kilometers per second. However, when light enters a medium, it interacts with the atoms or molecules of the material, which can slow it down. The speed of light in a medium is typically denoted as "v" and is slower than its speed in a vacuum. The relationship between the speed of light in a vacuum (c), the speed of light in a medium (v), and the refractive index (n) of the medium is given by the equation: v = c/n. The refractive index represents the factor by which the speed of light is reduced in the medium.
Wavelength of Light: The wavelength of light also changes as it passes through a medium. The wavelength is a measure of the distance between successive peaks or troughs of a light wave. When light enters a medium, its wavelength can be altered due to the interactions between the light and the atoms or molecules of the material. The relationship between the wavelength of light in a vacuum (λvacuum) and the wavelength of light in a medium (λmedium) is given by the equation: λmedium = λvacuum/n, where n is the refractive index of the medium.
It's important to note that while the speed and wavelength of light are affected by passing through a medium, the frequency of light remains constant. The frequency (f) of light represents the number of wave cycles passing a given point per unit of time and is inversely proportional to the wavelength (λ). Therefore, as the speed and wavelength of light change in a medium, the frequency remains the same.
The phenomenon of light refraction and the changes in speed and wavelength are fundamental concepts in optics and have various practical applications, including lenses, prisms, and the bending of light in different media.