题目内容
如图所示,有一范围足够大的匀强磁场,磁感应强度
,磁场方向垂直纸面向里。在磁场中有一半径
的金属圆环,磁场与圆环面垂直,圆环上分别接有灯
、
,两灯的电阻均为
。一金属棒MN与圆环接触良好,棒与圆环的电阻均忽略不计。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242235009263331.jpg)
(1)若棒以
的速率在环上向右匀速滑动,求棒滑过圆环直径的瞬时MN中的电动势和流过灯
的电流;
(2)撤去金属棒MN,若此时磁场随时间均匀变化,磁感应强度的变化率为
,求回路中的电动势和灯
的电功率。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223456402507.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223457322534.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223458243309.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223459397340.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223500068552.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242235009263331.jpg)
(1)若棒以
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223501331608.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223458243309.png)
(2)撤去金属棒MN,若此时磁场随时间均匀变化,磁感应强度的变化率为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223503453834.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223458243309.png)
(1) 0.8V 0.4A (2) 0.64V 5.12×10-2W
试题分析:(1)等效电路如图1所示
MN中的电动势
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223506089903.png)
MN中的电流
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223507587938.png)
流过灯
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223458243309.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223510021684.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242235114402511.jpg)
(2)等效电路如图2所示
回路中的电动势
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223511893392.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223513187994.png)
回路中的电流
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223514435949.png)
灯
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824223458243309.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242235167601016.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242235179922062.jpg)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目