题目内容
如图所示,金属杆ab以恒定的速率v在光滑平行金属导轨上向右滑行,设整个电路总电阻保持不变,匀强磁场与导轨所在平面垂直,下列叙述正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241322554531513.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241322554531513.png)
A.ab杆中的电流强度与速率v成正比 |
B.电路产生的电热功率与速率v成正比 |
C.磁场作用于ab杆的安培力与速率v的平方成正比 |
D.外力对ab杆做功的功率与速率v的平方成正比 |
AD
ab杆切割磁感线产生的感应电动势
,感应电流
,A正确;电路产生的电热功率
,B错误;磁场作用于ab杆的安培力
,C错误;杆匀速,
,所以外力对ab杆做功的功率
,D正确。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132255516530.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132255640859.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241322556721172.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241322557031072.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824132255734875.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241322557811087.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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