1
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在从前的视频中我们讨论过流过电线的电流

2
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能够产生感应磁场

3
00:00:07,101 --> 00:00:09,503
在这个视频中我们会讲到

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它的反定则

5
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磁场的改变如何在闭合电路中影响或感生电流

6
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我们现在要从（磁场的）改变着手

7
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实际上我们先来关注一下磁通量

8
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闭合电路里的磁通量