题目内容
如图所示,用铝板制成“
”形框,将一质量为m的带电小球用绝缘细线悬挂在框内,让整体在垂直向里的匀强磁场中做匀速运动时,悬线拉力为T,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241552084814326.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241552083561192.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241552084814326.jpg)
A.向左匀速运动时,悬线竖直,T=mg |
B.向左匀速运动时,悬线竖直,T<mg |
C.向右匀速运动时,悬线竖直,T=mg |
D.不论是向左还是向右匀速运动,只要v的大小选择合适,都可能使T=O |
AC
试题分析:整体移动中,铝板产生感应电流为上到下,把铝板看成一个电源,则下为正,上为负极。设小球带正点荷,则小球受竖直向下的洛仑磁力,向上的电场力,
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824155208496731.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824155208637583.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824155208746513.png)
点评:做该题的关键是分析出铝板间的电场方向,
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目