题目内容
如图所示,a、b、c为不同材料做成的电阻,b与a的长度相等,横截面积是a的两倍;c与a的横截面积相等,长度是a的两倍.当开关闭合后,三个理想电压表的示数关系是V1∶V2∶V3=1∶1∶2.关于三种材料的电阻率ρa、ρb、ρc,下列说法中正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250010312216214.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250010312216214.png)
A.ρa是ρb的2倍 | B.ρa是ρc的2倍 |
C.ρb是ρc的2倍 | D.ρc是ρa的2倍 |
C
试题分析:根据串联电路的电压关系,Ra:Rb:Rc=V1:V2:V3=1:1:2,根据
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001031237545.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001031253527.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001031268852.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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