What happens to light as it travels through a transparent medium like glass?

When light travels through a transparent medium such as glass, it slows down due to the interaction of the light waves with the material. This change in speed occurs because light waves are absorbed and re-emitted by the atoms in the glass, which takes time and effectively reduces the speed of light compared to its speed in a vacuum.

In a vacuum, light travels at its maximum speed of approximately 299,792 kilometers per second. However, in a medium like glass, the refractive index comes into play, which quantifies how much the speed of light is reduced. The refractive index of glass is typically greater than one, meaning light travels slower in glass than in a vacuum.

This phenomenon is important in many applications, including optics and the design of lenses, where controlling the speed and direction of light is crucial. Understanding that light slows down in transparent materials is fundamental to grasping concepts such as refraction and the behavior of light as it transitions between different media.