题目内容
如图所示的两种电路中,电源相同,各电阻器阻值相等,各电流表的内阻相等且不可忽略不计.电流表A1、A2、A3和A4读出的电流值分别为I1、I2、I3和I4.下列关系式中正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241518361714880.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241518361714880.png)
A.I1=I 3 | B.I 1<I 4 | C.I 2=2I 1 | D.I 2<I 3+I 4 |
BD
试题分析:电流表有内阻且相等,甲图并联支路两端的电压和乙图中并联支路两端的电压不同,电流表
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151836327556.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151836327556.png)
AB、甲图中,电流表A2分一部分电压,并联部分的电压比乙图中并联部分的电压小,电流表
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151836327556.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151836701431.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151836779426.png)
C、甲图中,电流表
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151836919349.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151837122511.png)
D、甲图总电阻为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241518372001435.png)
乙图总电阻为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151837387846.png)
由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241518374342235.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151837512516.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824151837653554.png)
故选BD
点评:分析电路图得出两图中支路两端的电压不同是解决本题的关键。
![](http://thumb2018.1010pic.com/images/loading.gif)
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