题目内容
如图所示,在开关S闭合时,质量为m的带电液滴处于静止状态,下列判断正确的是 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250014083742738.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250014083742738.png)
A.保持开关S闭合,将上极板稍向左平移,液滴将会向上运动 |
B.保持开关S闭合,将上极板稍向下平移,电流表中会有a→b的电流 |
C.将开关S断开,将上极板稍向左平移,液滴仍保持静止 |
D.将开关S断开,将上极板稍向下平移,电流表中会有b→a的电流 |
B
试题分析:开始时向上的电场力等于液滴的重力,即
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001408389746.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001408405818.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001408405818.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
练习册系列答案
相关题目