The fundamental force associated with electric and magnetic fields. The electromagnetic force is carried by the photon and is responsible for atomic structure, chemical reactions, the attractive and repulsive forces associated with electrical charge and magnetism, and all other electromagnetic phenomena. Like gravity, the electromagnetic force has an infinite range and obeys the inverse-square law. The electromagnetic force is weaker than the strong nuclear force but stronger than the weak force and gravity. Some scientists believe that the electromagnetic force and the weak nuclear force are both aspects of a single force called the electroweak force.