在《自感现象》这一节内容中,教科书里出现了如下一个演示实验: 一只小灯泡A和一个带有铁心的线圈L组成如图1所示的电路图,当电开关S断开时,发现小灯泡A不是立即熄灭,而是闪亮一下才熄灭。解释原因是:由于电路断开的瞬间,通过线圈的电流突然减弱,穿过线圈的磁通量也就很快地减小,为阻碍线圈中的磁通量的变化,从而在线圈中产生了一个 In the section “Self-Induction Phenomenon”, the following demonstration experiment appeared in the textbook: A small light bulb A and a coil L with a core form a circuit diagram as shown in Fig. 1, when the electric switch S is disconnected. , Found that light bulb A is not extinguished immediately, but only shines before it goes out. The reason for the explanation is that since the current passing through the coil abruptly weakens due to the moment the circuit is disconnected, the magnetic flux passing through the coil is rapidly reduced. In order to obstruct the change of the magnetic flux in the coil, a coil is generated in the coil.