题目内容
如图所示,交变电流电压的瞬时表达式u="311sin157t" V时,三个电流表的示数相同,若电源电压改为u′="311sin314t" V时,则 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241359543396495.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241359543396495.png)
A.电流表![]() | B.电流表![]() |
C.电流表![]() | D.电流表![]() ![]() ![]() |
C
根据
当交变电流电压的瞬时表达式u="311sin157t" V变为u′="311sin314t" V时角速度增大,交流电的有效值不变,所以电流表
的示数不变,故交流电的频率增大,L的感抗增大,容抗减小,所以电流表
的示数减小,电流表
的示数增大,所以选C
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135954651572.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135954479419.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135954386414.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824135954432427.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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