题目内容
如图所示,阻值为R的金属棒垂直放在水平光滑金属导轨上,导轨电阻不计,匀强磁场垂直导轨平面。金属棒从图示位置ab分别以v和2v的速度沿导轨匀速滑到a1b1位置,则在这两次过程中
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241537498716022.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241537498716022.png)
A.回路电流I1:I2=1:2 |
B.产生热量Q1:Q2=1:2 |
C.通过金属棒任一截面的电荷量q1:q2=1:2 |
D.外力功率P1:P2=1:2 |
AB
试题分析:A、由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153750120527.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153750198606.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153750510662.png)
B、由焦耳定律有
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153750604946.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153750666603.png)
C、由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153750729955.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153750885513.png)
D、金属棒匀速运动,外力与安培力相等,则外力的功率为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153751119855.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153751321555.png)
故选AB
点评:在电磁感应与电路结合的题目中,产生电磁感应的部分导体起到电源的作用,导体切割磁感线运动中,安培力是联系力与电磁感应的桥梁。
![](http://thumb2018.1010pic.com/images/loading.gif)
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