The dual nature of light, being both a wave and a particle, is one of the fundamental principles of quantum mechanics. This concept, known as wave-particle duality, suggests that light can exhibit characteristics of both waves and particles depending on how it is observed or measured.
The wave nature of light refers to its ability to exhibit phenomena such as interference and diffraction, similar to other types of waves such as sound waves or water waves. When considering light as a wave, it is described by properties like wavelength, frequency, and amplitude. This wave-like behavior is evident in phenomena like the interference patterns observed in the famous double-slit experiment.
On the other hand, the particle nature of light is associated with discrete packets of energy called photons. Each photon carries a specific amount of energy that is proportional to its frequency. When interacting with matter, light can behave as if it consists of individual particles. This is particularly apparent in the photoelectric effect, where light can eject electrons from a material when it strikes it, and the energy of the ejected electrons depends on the frequency of the light.
The difference between light and macroscopic objects like tables lies in their fundamental properties and scale. Light, as a fundamental particle, exhibits wave-particle duality due to the principles of quantum mechanics. In contrast, macroscopic objects like tables are composed of an enormous number of particles (atoms and molecules) and do not exhibit wave-like behaviors at macroscopic scales. While quantum mechanics also applies to the microscopic constituents of macroscopic objects, their collective behavior averages out the wave-like properties, leading to classical behavior described by classical physics. In other words, the scale and complexity of macroscopic objects make their wave-like properties negligible and not readily observable.