题目内容
如图,理想变压器原线圈输入电压u=
,副线圈电路中
为定值电阻,R是滑动变阻器。
和
是理想交流电压表,示数分别用
和
表示;
是理想交流电流表,示数分别用
和
表示。下列说法正确的是
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082419011533221068.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190113725275.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190113975219.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190114209737.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190114209733.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190114224219.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190114568223.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241901148021416.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190114817202.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190115051209.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/2014082419011533221068.png)
A.![]() ![]() |
B.![]() ![]() |
C.滑片P向下滑动过程中,![]() ![]() |
D.滑片P向下滑动过程中,![]() ![]() |
C
试题分析:电流表的示数都是交流电的有效值,故AB错误;当P向下滑动时,因为原副线圈两端的电压之和变压器的匝数有关,所以匝数不变,副线圈两端的电压不变,故
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190114568223.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190117906201.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190118187303.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824190114817202.png)
故选C
点评:电路的动态变化的分析,总的原则就是由部分电路的变化确定总电路的变化的情况,再确定其他的电路的变化的情况,即先部分后整体再部分的方法.
![](http://thumb2018.1010pic.com/images/loading.gif)
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