题目内容
右图为一理想变压器,其原副线圈匝数比n1:n 2=1:10,副线圈与阻值R=20Ω的电阻相连。原线圈两端所加的电压u=20
sin100πt(V),则( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241306238222078.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130623806352.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241306238222078.png)
A.交流电压表的示数为20![]() |
B.副线圈输出交流电的频率为50Hz |
C.电阻R上消耗的电功率为2kW |
D.原线圈中电流的最大值为100A |
BC
交流电压表的示数为有效值,原线圈的有效电压为:
=20V,所以A错;
原副线圈电流频率相同,由瞬时电压表达式知:
,所以f=50HZ,B对;
电阻R上消耗的电功率为:
,因为原副线圈匝数比n1:n 2=1:10,所以
=200V,所以P=2000W,C对;根据输出功率决定输入功率,
,所以
,最大电流时有效电流的
倍,所以100
A,C对;D错。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130623869700.png)
原副线圈电流频率相同,由瞬时电压表达式知:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130623900545.png)
电阻R上消耗的电功率为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130623931626.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130623947377.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130623978565.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130624009743.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130624040336.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824130624040336.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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