tailieunhanh - Chapter XIII Electromagnetic Oscilation, Eletromagnetic Field and Wave

We have known the close connection between changing eletric fields and magnetic fields. They can create each other and form a system of electromagnetic fields. Electromagnetic fields can propagate in the space (vacuum or material environment). We call them electromagnetic waves. They play a very important role in science and technology. | GENERAL PHYSICS II Electromagnetism Thermal Physics 4 8 2008 1 _Chapter XIII Electromagnetic Oscilation Eletromagnetic Field and Wave 1. Oscillating circuits 2. System of Maxwell s equations 3. Maxwell s equations and electromagnetic waves 4 8 2008 2 We have known the close connection between changing eletric fields and magnetic fields. They can create each other and form a system of electromagnetic fields. Electromagnetic fields can propagate in the space vacuum or material environment . We call them electromagnetic waves. They play a very important role in science and technology. In this chapter we will study how can describe electromagnetic fields what are their properties in comparison with mechanical waves . First we consider the oscillating circuits in which there exist oscillating currents and voltages. They are sources for electromagnetic fields 4 8 2008