What is the basic unit of light or any other form of electromagnetic radiation?

The basic unit of light and other forms of electromagnetic radiation is known as a photon. Photons are elementary particles that carry electromagnetic force. They are massless and travel at the speed of light in a vacuum, which allows them to transport energy across vast distances in the form of electromagnetic radiation, including visible light, ultraviolet light, infrared radiation, and more.

Photons play a crucial role in various physical phenomena, such as the photoelectric effect and Compton scattering, showing their dual nature as both particles and waves. This dual nature makes them fundamental to quantum mechanics and helps explain how light interacts with matter.

Other options such as electrons, neutrinos, and quarks are particles that serve different roles in physics. Electrons are negatively charged particles that are fundamental to atomic structure, neutrinos are nearly massless particles that interact very weakly with matter, and quarks are the building blocks of protons and neutrons found in atomic nuclei. None of these particles represent the basic unit of electromagnetic radiation like photons do.