题目内容
电场中有A、B两点,一个点电荷在A点的电势能为1.2×10-8 J,在B点的电势能为0.80×10-8 J.已知A、B两点在同一条电场线上如图所示,该点电荷的电荷量为1.0×10-9C,那么( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523408203.png)
A.该电荷为负电荷 B.该电荷为正电荷
C.A、B两点的电势差UAB="4.0" V D.把电荷从A移到B,电场力做功为W=4.0J
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523408203.png)
A.该电荷为负电荷 B.该电荷为正电荷
C.A、B两点的电势差UAB="4.0" V D.把电荷从A移到B,电场力做功为W=4.0J
A
试题分析:根据电场力做功
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523502692.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523564745.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523658842.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523736982.png)
正确B错误。根据
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523502692.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523861784.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824150523986615.png)
点评:此类题型要注意由于做功、电势差等都是标量,因此在计算时应将q正负、电势差正负、做功正负的符号带入,才能得到正确答案。
![](http://thumb2018.1010pic.com/images/loading.gif)
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