Yes, light can indeed be described as both "wave-like" and "particle-like." This duality is a fundamental concept in physics known as the wave-particle duality.
According to classical physics, light was thought to behave solely as a wave. This wave nature of light was well described by James Clerk Maxwell's electromagnetic theory, which successfully explained various phenomena, such as interference and diffraction. However, in the late 19th century, experimental evidence began to suggest that light also exhibited particle-like behavior.
The particle-like behavior of light was first theorized by Albert Einstein in 1905 when he proposed the concept of photons. According to Einstein's theory of the photoelectric effect, light is composed of discrete packets of energy called photons. These photons behave as particles, carrying energy and momentum. The photoelectric effect refers to the ejection of electrons from a material when it is illuminated by light, and it can be explained by the interaction between photons and electrons as particles.
Subsequent experiments, such as the Compton scattering and the double-slit experiment, further supported the wave-particle duality of light. In the Compton scattering experiment, X-rays were scattered off electrons, and the scattering patterns indicated that the X-rays behaved as particles. However, when light passes through a double-slit apparatus, it produces an interference pattern characteristic of waves, indicating its wave-like nature.
Quantum mechanics provides a more comprehensive framework for understanding the wave-particle duality. In quantum theory, particles like photons are described by wavefunctions, which are mathematical descriptions that exhibit wave-like properties. The wavefunction can be used to calculate the probability distribution of finding a particle at a particular location or having a specific energy.
In summary, light can be described as both wave-like and particle-like. Its wave-like behavior is evident in phenomena such as interference and diffraction, while its particle-like behavior is observed in the photoelectric effect and various scattering experiments. The wave-particle duality is a fundamental concept in quantum mechanics that allows us to understand the behavior of light and other particles at the microscopic level.