题目内容
如图所示,理想变压器原、副线圈的匝数比为2:1,电阻
,原线圈两端接一正弦式交变电流,电压u随时间t变化的规律为
(V),时间t的单位是s。那么,通过电阻R的电流有效值和频率分别为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241526208953153.png)
A.1.0A、20Hz B.
A、20Hz
C.
A、10Hz D.1.0A、10Hz
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152620537535.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152620802793.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241526208953153.png)
A.1.0A、20Hz B.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621098319.png)
C.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621098319.png)
D
试题分析:由
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241526214411013.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621504730.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621582844.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621644567.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621707853.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621769767.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621863601.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152621972681.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824152622159492.png)
故选D
点评:牢记交流电的“四值”:最大值、瞬时值、有效值和平均值,并知道每个值的物理意义及用法。
![](http://thumb2018.1010pic.com/images/loading.gif)
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