在人教版选修3-2的《交变电流》的教学中,教材出示的产生交流电的示意图如下图1,教材根据图1,用法拉第电磁感应定律可以推导,它的电动势E随时间的变化规律为E=E_msinωt。在相应的教师用书中,我们可以发现得到这样的结论,基于的是在匀强磁场中,我们可以得到上面正弦交 In the PEP 3-2 “alternating current” teaching, the textbook shows the generation of alternating current diagram shown in Figure 1, textbook according to Figure 1, with Faraday’s law of electromagnetic induction can be derived, its electromotive force E with time changes The law is E = E_msinωt. In the corresponding teacher’s book, we can find that we can get the conclusion based on that in a strong magnetic field, we can get the above sinusoidal cross