长为L的铜棒,以距端点r处为支点,以角速率ω绕通过支点且垂直于铜棒的轴转动.设磁感强度为B的均匀磁场与轴平行,求棒两端的电势差.
正确答案:
如图(a)所示,在棒上距点O为l处取导体元dl,则![](https://img.274949.com/Images/2020-04/04/40mk63vu.jpg)
因此棒两端的电势差为
![](https://img.274949.com/Images/2020-04/04/sy8upw7h.jpg)
当L>2r时,端点A处的电势较高
![](https://img.274949.com/Images/2020-04/04/40mk63vu.jpg)
因此棒两端的电势差为
![](https://img.274949.com/Images/2020-04/04/sy8upw7h.jpg)
当L>2r时,端点A处的电势较高
答案解析:有
![](/editor/images/201705/qrcode_for_gh_573e2a458573_258.jpg)
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长为L的铜棒,以距端点r处为支点,以角速率ω绕通过支点且垂直于铜棒的轴转动.设磁感强度为B的均匀磁场与轴平行,求棒两端的电势差.
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