题目内容
如图所示,在点电荷Q产生的电场中,将两个带正电的试探电荷q1、q2分别置于A、B两点,实线为等势线。取无穷远处为零电势点,若将q1、q2移动到无穷远的过程中外力克服电场力做的功相等,则下列说法正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241537368912732.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241537368912732.png)
A.A点电势大于B点电势 |
B.A、B两点的电场强度相等 |
C.q1在A点的电势能小于q2在B点的电势能 |
D.q1的电荷量小于q2的电荷量 |
D
试题分析:由于将两个带正电的试探电荷移动到无穷远的过程中外力克服电场力做的功,所以电荷Q带负电,设无穷远处电势为零,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153736969582.png)
A、
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153737032666.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153737297677.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153736969582.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153737500528.png)
B、由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153737718674.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153737905520.png)
C、电荷在无穷远处电势能为零,将
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153738311364.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153738514385.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153738311364.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153738514385.png)
D、由于将
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153738311364.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153738514385.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153739699767.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153736969582.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153738311364.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153738514385.png)
故选D
点评:本题关键是确定A、B两点的电势关系。一般设无穷远处电势为零,根据A、B两点的等势面位置可以确定和无穷远处的电势差,就可以确定电势关系,
![](http://thumb2018.1010pic.com/images/loading.gif)
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