题目内容
如图所示,R1=10Ω,R2=20Ω,R3=30Ω,接在电源上时,功率分别为P1、P2、P3,则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160218379415.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160218379415.png)
A.P1>P2>P3 | B.P1=P2=P3 |
C.P2<P1<P3 | D.P1<P2<P3 |
C
试题分析:设R2两端电压为U,则
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160218488839.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824160218785978.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241602189561018.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241602191591284.png)
点评:本题难度较小,并联时电压相等,明确不变量,根据电功率公式求解
![](http://thumb2018.1010pic.com/images/loading.gif)
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题目内容
A.P1>P2>P3 | B.P1=P2=P3 |
C.P2<P1<P3 | D.P1<P2<P3 |