在电磁感应现象中,切割磁感线的导体或磁通量发生变化的回路中将产生感应电动势,该导体或回路等效于电源.在一些电磁感应问题中,这样的电源有两个,我们称之为“双电源”问题.这类问题在历年高考中多次出现,学生解答时感到比较困难,往往考虑不周顾此失彼,造成解题错误.下面列举几例加以分析. In the electromagnetic induction phenomenon, an induced electromotive force is generated in the conductor that cuts the magnetic induction line or in the circuit where the magnetic flux changes, and the conductor or circuit is equivalent to the power supply. In some electromagnetic induction problems, there are two such power sources, which we call For the “dual power” problem. This type of problem has occurred many times in the college entrance examination over the years, students find it difficult to answer, often consider bad luck, resulting in the wrong solution. Here are a few examples to be analyzed.