Wave-particle duality holds that both light and matter exhibit complementary wave-like and particle-like behavior, a principle classical mechanics cannot accommodate but quantum mechanics explains. The photoelectric effect demonstrates light's particle nature: photons carry discrete quanta of energy E = hν (Planck's constant times frequency), so an electron is ejected from a metal only when incident photon energy exceeds the metal's work function (hν₀), with excess energy appearing as the ejected electron's kinetic energy (KE = hν − hν₀). This belongs to the foundations of quantum mechanics within physical chemistry/atomic physics, motivated by classical mechanics' failure to explain atomic stability (predicting electron collapse into the nucleus).
Wave-particle duality holds that both light and matter exhibit complementary wave-like and particle-like behavior, a principle classical mechanics cannot accommodate but quantum mechanics explains. T…