题目内容
一个矩形线圈在一匀强磁场中绕垂直于磁场方向的中心轴匀速转动,产生的交变电动势表达式为e="311sin314t" V,试求:
(1)交变电动势的最大值、有效值和频率;
(2)若矩形线圈是100匝,线圈平面面积为0.02 m2,匀强磁场的磁感应强度B是多少;
(3)当线圈平面从中性面开始转过
时,电动势的瞬时值是多大.
(1)交变电动势的最大值、有效值和频率;
(2)若矩形线圈是100匝,线圈平面面积为0.02 m2,匀强磁场的磁感应强度B是多少;
(3)当线圈平面从中性面开始转过
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120648186363.gif)
(1)311 V 220 V 50 Hz (2)0.5 T (3)220 V
(1)将e=311sin314t(V)跟e=Emaxsinωt对应比较,可知:Emax="311" V ①
有效值:E=
="220" V ②
频率:f=
Hz="50" Hz ③
(2)由Emax=NBωS得 B=
④
(3)线圈从中性面转过
,即ω·t=![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120648186363.gif)
e=311sin
V=311×0.707 V="220" V. ⑤
有效值:E=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120648202616.gif)
频率:f=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120648218620.gif)
(2)由Emax=NBωS得 B=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241206482181030.gif)
(3)线圈从中性面转过
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120648186363.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120648186363.gif)
e=311sin
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120648186363.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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