“断电自感”现象是高中物理教学中一个较难的知识点,很多学生对于这块知识的掌握与处理是建立在机械记忆的层面上,他们知道当开关S断开后线圈和灯泡将组成闭合回路,线圈充当电源的作用,灯泡的电流将逐渐减小,并在这一过程中伴随着“闪亮一下”的可能出现.同时,也记住了灯泡是否闪亮取决于电路稳定时通过线圈的电流IL与通过灯泡电流IA大小的比较.但一次考试中出现的一道选择题却让我们重新审视这个知识点的教学. The “power failure self-inductance” phenomenon is a difficult knowledge point in high school physics teaching. Many students grasp and handle this knowledge based on the mechanical memory level. They know that when the switch S is disconnected, the coil and The bulb will form a closed loop, and the coil will act as a power source. The current of the bulb will gradually decrease, and in the process it will be accompanied by a “sparkle”. At the same time, it will be remembered whether the bulb is shining or not. When the circuit is stable, the current IL passing through the coil is compared with the size of the current IA through the bulb. However, a multiple-choice question in an examination allows us to re-examine the teaching of this knowledge point.