题目内容
图所示的匀强电场场强为103N/C,ab=dc=4cm,bc=ad=3cm.则下述计算结果正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205020027929.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205020027929.png)
A.ab之间的电势差为40V |
B.ac之间的电势差为50V |
C.将q=-5×10-3C的点电荷沿矩形路径abcd移动一周,电场力做功是-0.25J |
D.将q=-5×10-3C的点电荷沿abc或adc从a移动到c,电场力做功都是-0.25 |
A
试题分析:ab之间的电势差
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242050212601054.png)
由图看出,b、c在同一等势面上,电势相等,则ac之间的电势差等于ab之间的电势差,为40V.故B错误.
将
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205022055571.png)
将
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824205022055571.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242050235681124.png)
故选A
点评:电场力做功与重力做功相似,只与电荷初末位置有关,与路径无关.基础题.
![](http://thumb2018.1010pic.com/images/loading.gif)
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