And electromagnetism is closely related to classical electrodynamics

And electromagnetism is closely related to classical electrodynamics, both in content and there is no principle difference. In general, the electromagnetic emphasis on  electric meter  study of electromagnetic phenomena, from the extensive study of electromagnetic phenomena summarized the basic laws of electromagnetism; classical  electric transformer  the emphasis on the theoretical aspects of it to Maxwell's equations and the Lorentz force based to study the electromagnetic field  Voltage stabilizer , electromagnetic excitation, radiation and propagation, as well as the interaction between charged particles and electromagnetic fields and other electromagnetic problems, it can be said that the generalized electromagnetism contains classical electrodynamics.