题目内容
一矩形线圈,在匀强磁场中绕垂直磁感线的对称轴转动,形成如图16所示的交变电动势图象,试根据图象求出:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333164122755.png)
(1)线圈转动的角速度;
(2)电动势的有效值;
(3)t = 1.0×10?2s时,线圈平面和磁场方向的夹角。
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241333164122755.png)
(1)线圈转动的角速度;
(2)电动势的有效值;
(3)t = 1.0×10?2s时,线圈平面和磁场方向的夹角。
(1)105rad/s(2)14.1 V(3)![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316459551.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316459551.png)
(1)(3分)由图象得,交变电动势的周期T=6×10
s
而周期![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316568614.png)
代入数值解得
105rad/s
(2)(3分)由图象得,交变电动势的最大值为Em=20V,
电动势的有效值
代入数值解得
14.1 V
(3)(3分)交变电动势的瞬时值表达式![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316709719.png)
线圈平面和磁场方向的夹角
将t = 1.0×10?2s代入,解得![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316459551.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316490257.png)
而周期
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316568614.png)
代入数值解得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316600326.png)
(2)(3分)由图象得,交变电动势的最大值为Em=20V,
电动势的有效值
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316631629.png)
代入数值解得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316678333.png)
(3)(3分)交变电动势的瞬时值表达式
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316709719.png)
线圈平面和磁场方向的夹角
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316787693.png)
将t = 1.0×10?2s代入,解得
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824133316459551.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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