题目内容
某电路如图所示,已知电池组的总内阻r=1Ω,外电路电阻R=5Ω,理想电压表的示数U=3.0V,则电池组的电动势E等于
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241604349893085.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241604349893085.jpg)
A.3.0V | B.3.6V | C.4.0V | D.4.2V |
B
试题分析:由欧姆定律,得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160435004719.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241604351291098.png)
故选B
点评:由已知条件,由欧姆定律求出电阻的电流I,再由闭合电路欧姆定律,求出电池的电动势.
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.3.0V | B.3.6V | C.4.0V | D.4.2V |