ABSTRACT
Electrodynamics is the branch of physics concerned with the interaction of charged particles and electromagnetic fields. Most macroscopic phenomena fall under this area of scientific knowledge, including optics, from lasers to astronomy; chemistry, from biomolecular physics to inorganic compounds; and solid-state physics, from semiconductors to superconductivity. The other three known interactions, namely gravitation and the weak and strong interactions, are somewhat more limited in scope. They apply either to very largescale systems, such as galaxies, star clusters, and the topology of the universe, or to processes involving subatomic particles, including quarks, neutrinos, and charged leptons. The latter is exemplified by nuclear fusion reactions of elements lighter than iron in stars, for the strong force, and
β
-decay and the recently observed neutrino oscillations, for the weak interaction.
