The speed of light varies in non-vacuum mediums, as it is influenced by the refractive index, which depends on the wavelength of light. This means that different frequencies of light can travel at different speeds when passing through materials like glass. It is important to note that light does not "move" through a medium in the same way sound does; instead, it interacts with the medium, which affects its speed. The concept of dispersion highlights how the refractive index changes with wavelength. Understanding these principles is crucial for applications in optics and photonics.
