经历从看得见的具体有形的闭合电路到假想的、虚拟的闭合电路去理解感生电动势的产生,逐步体会均匀变化的磁场所产生的稳定的感生电场的客观存在性,正确认识电磁感应的实质. Experience the induced electromotive force from the visible and visible closed circuit to the imaginary and virtual closed circuit. Gradually realize the objective existence of the stable induced electric field generated by the uniform magnetic field, and correctly understand the electromagnetic induction. The substance.