题目内容
(4分)如图甲所示电路中,电压表V1和V2的示数之比为1:3,则定值电阻R1:R2= ,消耗的功率P1:P2= ;若将电阻R1、R2改接为如图乙所示的电路,则电流表A1、A2的示数之比为 ,在相同时间内R1、R2消耗的电能之比为 .
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250026579546900.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250026579546900.png)
1:2;1:2;2:3;2:1
试题分析:电压表V1测R1两端电压,V2测R1、R2的总电压,根据串联电路的分压公式得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002658001932.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002658032583.png)
改接成图乙的电路后,电流表A1测通过R1的电流I1,A2测干路电流I,根据并联电路的分流公式得:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002658048735.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002658064755.png)
在相同时间内R1、R2消耗的电能之比为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825002658079875.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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