题目内容
正弦交变电源与电阻R、交流电压表按照图甲中所示的方法连接,R=10 Ω,交流电压表的示数是10 V.图乙是交变电源输出电压u随时间t变化的图像,则 ( ).
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242131165484638.png)
甲 乙
A.通过R的电流iR随时间t变化的规律是iR=
cos 100πt(A)
B.通过R的电流iR随时间t变化的规律是iR=
cos 50πt(A)
C.R两端的电压uR随时间t变化的规律是uR=
cos 100πt(V)
D.R两端的电压uR随时间t变化的规律是uR=
cos 50πt(V)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242131165484638.png)
甲 乙
A.通过R的电流iR随时间t变化的规律是iR=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824213117250344.png)
B.通过R的电流iR随时间t变化的规律是iR=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824213117250344.png)
C.R两端的电压uR随时间t变化的规律是uR=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824213119059412.png)
D.R两端的电压uR随时间t变化的规律是uR=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824213119059412.png)
A
试题分析:伏特表的示数为交流电的有效值10 V,则交流电的最大值为
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824213121056439.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824213122242778.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242131233961032.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242131246441050.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408242131256121740.png)
故选A
点评:本题考查了交流电的描述,要明确交流电正余弦两种描述方法,以及公式中各个物理量的含义
![](http://thumb2018.1010pic.com/images/loading.gif)
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