Light exhibits both particle-like and wave-like behavior, which is known as the wave-particle duality of light. This phenomenon is a fundamental concept in quantum mechanics.
The behavior of light as a particle is explained by the photon theory, which states that light consists of discrete particles called photons. Each photon carries a specific amount of energy and momentum. This particle nature of light is observed in phenomena such as the photoelectric effect and Compton scattering.
On the other hand, the wave nature of light is described by electromagnetic wave theory. According to this theory, light propagates as a wave of oscillating electric and magnetic fields. It exhibits characteristics like diffraction, interference, and polarization, which are typical of wave phenomena.
The famous double-slit experiment provides evidence for the wave-particle duality of light. In this experiment, a beam of light is directed at a barrier with two narrow slits. The light passing through the slits creates an interference pattern on a screen behind the barrier, similar to what is observed when waves pass through two slits. This suggests the wave-like nature of light.
However, when the experiment is performed with very low light intensity, it is observed that individual photons are detected on the screen. This demonstrates the particle-like behavior of light. The interference pattern gradually emerges as more and more photons are detected, confirming the wave-particle duality.
So, the double-slit experiment is a classic demonstration that provides insight into the dual nature of light. It shows that light behaves both as particles (photons) and waves, and the behavior observed depends on the experimental setup and conditions.