A photon does not possess a physical size; it is classified as a point particle with no definable width. The concept of size in atoms arises from the spatial arrangement of point particles, such as electrons and protons, rather than the particles themselves. Protons and neutrons, which constitute atomic nuclei, are also made up of quarks, further emphasizing the point-like nature of fundamental particles. Understanding these distinctions clarifies why individual atoms cannot be observed directly, as they are smaller than the wavelength of visible light.
PREREQUISITESStudents and professionals in physics, particularly those interested in quantum mechanics, particle physics, and atomic theory.