Electromagnetism is a branch of physics. The broad sense of electromagnetism includes electricity and magnetism, but in a narrow sense, it is a subject that discusses the interaction between electrical and magnetic. It mainly studies the electromagnetic wave, the electromagnetic field and the related charge, the dynamics of the charged object, etc.
Electromagnetism is the discipline that studies the interaction between electricity and magnetism, the law and application. According to the viewpoint of modern physics, the magnetic phenomenon is produced by the motion electric charge, so it is necessary to contain the content of magnetism in different degree.
Electromagnetism becomes a complete branch discipline in physics from the original independent two sciences (electric and magnetic), mainly based on two important experiments, it is found that the magnetic effect of electric current and the variation of the magnetic field of electric effect. These two experimental phenomena, coupled with the hypothesis that Maxwell has a magnetic field generated by the variation of electric field, lay the whole theoretical system of the electromagnetism, and develop the electrical and electronic technology for the great influence of the modern civilization.
2. Classical Electrodynamics
Electromagnetics is closely related to classical electrodynamics, the two parties have no principle difference in content. Generally speaking, electromagnetism emphasizes experimental study of electromagnetic phenomena, summarizes the electromagnetism from a wide range of electromagnetic phenomena of the basic law; classical electrodynamics is focused on the theoretical aspects, it is based on Maxwell's equations and the Lorentz force based, electromagnetic field distribution, electromagnetic wave excitation, radiation and transmission, and of charged particles and electromagnetic interaction. It can also be said that the generalized electromagnetic contains the classical electrodynamics.
3. Magnetic Effects
1) Electric collision and spiral line
2) The rotation force and the center force
4. Physical Theory
1) Physical analogy
2) Ether vortex model
3) Displacement current
4) Electromagnetic equation set
5) Prediction of electromagnetic waves