由于高中生认知水平的局限,对于金属杆切割磁场(即回路面积S改变)的同时磁感应强度曰亦同时随时间发生变化而产生的电动势问题的理解认识和规律探究存在困难,且鲜有文献涉论该问题。本文旨在通过两种方法探究、推导出B、S同时变化产生的感应电动势以及由此而得到的一些教学启示。 Due to the limitations of high school students’ cognition level, it is difficult to understand and study the law of the electromotive force caused by the change of the magnetic induction intensity at the same time that the magnetic induction intensity of the metal rod is changed (with the change of the circuit area S) Concerned about the issue. The purpose of this paper is to explore and derive the induced electromotive force caused by the simultaneous changes of B and S by using two methods and some teaching implications.