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高中物理“自感”一节中,对“断电自感”现象是这样叙述的:“现在再来做(图4—16)的实验,把灯泡A和带铁芯的电阻较小的线圈L并联,接在直流电路里,接通电路灯泡正常发光后,再断开电路,这时可以看到灯泡A‘过一会儿才熄灭’。”教参中对“断电自感现象”的实验只介绍了一种现象—“闪亮”一下后熄灭。笔者认为“过一会儿才熄灭”应该有两种情况:一种是“闪亮”一下熄灭,另一种情况是“逐渐变暗”。出现这两种现象的原因分析如下:
In the “self-inductance” section of high school physics, the “power-off self-inductance” phenomenon is described as follows: “Now do another experiment (Figs. 4–16). Take the light bulb A and the coil L with a low resistance of the iron core. Connected in parallel, connected to the DC circuit, connected to the normal light bulb, and then disconnect the circuit, then you can see the bulb A ’to be extinguished after a while’. “The teaching of the experiment on the ”self-inductance phenomenon“ only A phenomenon was introduced - ”flashing" went off after a moment. The author believes that there should be two cases of “extinguishing after a while”: one is that “shiny” is extinguished and the other is “gradually darkening”. The reasons for these two phenomena are analyzed as follows: