题目内容
如图所示,B、C、D三点都在以点电荷+Q为圆心,半径为r的圆弧上,将一试探电荷从A点分别移到B、C、D各点时,电场力做功是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082415381114912089.png)
A.
B.
C.
D.![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153811633649.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082415381114912089.png)
A.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153811243668.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153811367669.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153811492667.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824153811633649.png)
D
试题分析:以+Q为圆心的圆周是一条等势线,B、C、D三点电势相等,则A与B、C、D三点的电势差U相等.根据电场力做功公式W=qU可知,电荷从圆内A点分别移到B、C、D各点时,电场力做的功相等,D对;
点评:难度较小,本题要抓住电场力做功的特点来判断:电场力做功只与起点、终点间的电势差有关,与路径无关,注意W和U的下角标
![](http://thumb2018.1010pic.com/images/loading.gif)
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