题目内容
(8分)如图所示,变阻器的滑片p位于其中点,变阻器的总电阻为2kΩ。
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250018024213896.png)
(1)当在ab两点间加上120V电压时,接在cd间的电压表读数为40V,试求此时变阻器消耗的总功率;
(2)当在cd两点间加上40V电压时,接在ab间的上述电压表读数为多少?
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250018024213896.png)
(1)当在ab两点间加上120V电压时,接在cd间的电压表读数为40V,试求此时变阻器消耗的总功率;
(2)当在cd两点间加上40V电压时,接在ab间的上述电压表读数为多少?
(1)8W;(2)20V
试题分析:(1)此时加在ac间的电压为80V
因此
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/201408250018024371071.png)
(2)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001802452781.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001802468978.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001802483610.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140825/20140825001802499981.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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