题目内容
如图所示,在x轴上坐标为-L处固定一点电荷-q,坐标为-2L处固定一点电荷+4q。A、B关于坐标原点O对称的两点,场强分别为EA,EB。将另一带正电的试探电荷由坐标原点O分别移到A和B的过程中,电场力所做的功分别为W1和W2,则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241528002832514.jpg)
A. EA<EB W1<W2 B. EA>EB W1<W2
C. EA>EB W1=W2 D. EA>EB W1>W2
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241528002832514.jpg)
A. EA<EB W1<W2 B. EA>EB W1<W2
C. EA>EB W1=W2 D. EA>EB W1>W2
D
试题分析:由真空点电荷的定义式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152800377674.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241528004551151.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152800533533.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152800595676.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152800767562.png)
故选D
点评:关键准确分析电场的分布情况,由电场分布情况确定电场强度的大小及电场力做功的多少。
![](http://thumb2018.1010pic.com/images/loading.gif)
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