题目内容
两根材料相同的均匀导线A和B,其长度分别为L和2L,串联在电路中时沿长度方向电势的变化如下图所示,则A和B导线的横截面积之比为 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241301157061519.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241301157061519.jpg)
A.2∶3 |
B.1∶3 |
C.1∶2 |
D.3∶1 |
B
由图象可知,两导线电压分别为UA=6V,UB=4V;由于它们串联,则3RB=2RA;由电阻定律可知,
,得
,选项B正确
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130115737744.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130115784545.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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