Electromagnetism
It is the one of the physical fields, and the electromagnetism (electromagnetism) is study to handle electricity and a phenomenon about the magnetism. In the engineering field, I can be called electric magnetics. A phenomenon electromagnetic as for the electromagnetism of the consideration intend for it. For an electromagnetic phenomenon, it is known from ancient times. Currently, it is known that all most phenomena around the body can understand it as an electromagnetic phenomenon. The electromagnetism is a theory system explaining these electromagnetic phenomena as an electric charge and interaction of the electromagnetic field. The electric charge is quantity of physics that is peculiar to a material, and it is quantity to express a material and the strength of ties with the electromagnetic field. It is quantity of physics that each space-time point has, and the electromagnetic field transmits action of the electricity between the material and action of the magnetism. For an electromagnetic field, I regard a group of the vector potential or the group of an electric field and the magnetic field as scalar potential. When I want to distinguish in particular these tupple, there is the thing that I call electromagnetic potential, the latter an electromagnetic field in the former. In the electric field / the magnetic field, observation is possible directly, but cannot determine the electromagnetic potential by observation uniformally. However, I cannot explain it in an electric field / the magnetic field, but it is thought that electromagnetic potential is quantity of essential physics in a thing (Baum effects) of the that there is the phenomenon that I can describe with the electromagnetic potential. The electromagnetic field gives an electric charge and current (the flow of the electric charge) power. This power is called Lorentz force. On the contrary, the existence of an electric charge / the electric current affects an electromagnetic field. The behavior of the electromagnetic field and the influence that an electric charge / an electric current gives an electromagnetic field are described by Maxwell equation. Lorentz force and the Maxwell equation are the most fundamental laws in the electromagnetism. As one of the solutions of the Maxwell equation, the electromagnetic wave which is the periodic vibration of the electromagnetic field is provided. In fact, "light" and the talked thing are kinds of the electromagnetic wave routinely. As for the electromagnetic wave, a name changes by a wavelength and outbreak mechanism: If a wavelength becomes shorter than electric wave, it, the long electromagnetic wave of a wavelength used for telecommunications is infrared, and a visible ray, ultraviolet rays, the electromagnetic wave which a wavelength has a shorter are called X-rays, gamma ray by outbreak mechanism.