The nature of light is often described as having both particle-like and wave-like properties. This duality is known as the wave-particle duality of light. In certain experiments and observations, light behaves like a particle, and in others, it behaves like a wave.
When light enters the eyes, it interacts with the cells in the retina, specifically the specialized cells called photoreceptors. These photoreceptor cells, known as rods and cones, are sensitive to light and are responsible for converting light signals into electrical signals that can be processed by the brain.
In terms of the particle-like behavior of light, individual photons, which are quanta of light, interact with the photoreceptor cells. Photons can be thought of as discrete particles of energy. When a photon reaches the retina, it can be absorbed by the photoreceptor cells. This absorption of photons by the photoreceptors triggers a series of biochemical and electrical processes that eventually lead to the perception of light and vision.
On the other hand, the wave-like nature of light also plays a role in vision. Light waves carry information about their frequency and amplitude, which determine the color and intensity of the light, respectively. The wave properties of light help determine the perceived qualities of the light, such as its color and brightness.
So, in summary, when light enters the eyes, it exhibits both particle-like and wave-like behavior. The particles of light, photons, can be absorbed by the photoreceptor cells, initiating the process of vision. At the same time, the wave properties of light influence the perception of color and brightness.