楞次定律揭示了判定感生电流的方向的规律,即“感生电流的磁场总是要阻碍引起感生电流的磁通量的变化”。楞次定律的核心思想是“阻碍”,只有深刻理解“阻碍”的含义,才能正确掌握定律的实质。 首先,阻碍不是阻止。因为磁通的变化是引起感应电流的必要条件,若这种变化被阻止,也就不可能继续产生感生电流了。其实原磁场的变化是由外界的各种因素决定的,如电流的变化、相对位置的变化,而与感生电流无关。例如一根磁棒从高处下落,竖直穿过一个 The Lenz’s law reveals the rule that determines the direction of the induced current, that is, “a magnetic field that induces a current always obstructs the change in the magnetic flux that causes the induced current.” The core idea of ​​Lenz’s law is “blocking”. Only by understanding the meaning of “impeding” can we master the essence of the law. First of all, the obstacle is not blocked. Because the change in magnetic flux is a necessary condition for induced currents, if this change is prevented, it is impossible to continue to generate induced currents. In fact, the change of the original magnetic field is determined by various factors of the outside world, such as the change of the current, the change of the relative position, and has nothing to do with the induced current. For example, a magnet bar falls from a height and passes vertically