What confirms the particle nature of radiation?

The photoelectric effect (option B) confirms the particle nature of radiation. In this phenomenon, observed by Albert Einstein and others, light is shown to behave as discrete packets of energy called photons. When light (often in the form of photons) strikes the surface of a material, it can transfer its energy to electrons in the material. If the energy of the photons exceeds the binding energy of the electrons, those electrons are ejected from the material, creating an electric current. This process occurs instantaneously and does not depend on the intensity of the light but rather on the energy of individual photons. The photoelectric effect contradicts classical wave theories of light, which predict a continuous transfer of energy rather than discrete packets. Therefore, the observation of the photoelectric effect provided strong evidence for the particle nature of radiation, leading to significant advancements in our understanding of quantum mechanics and the nature of light.