题目内容
一个闭合的矩形线圈放在匀强磁场中匀速转动,角速度为ω时,线圈中产生的交变电动势的最大值为E0,周期为T0,外力提供的功率为P0.若使线圈转动的角速度变为2ω,线圈中产生的交变电动势的最大值为E,周期为T,外力提供的功率为P.则E、T和P的大小为 ( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241416288095315.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241416288095315.jpg)
A.E=2E0,T=![]() |
B.E=E0,T=![]() |
C.E=2E0,T=T0,P=2P0 |
D.E=2E0,T=![]() |
D
设线圈为N匝,面积为S,所在区域磁感应强度为B,当角速度为ω时,产生的最大感应电动势E0=NBSω,周期T0=
,外力提供的功率P0=
=
=
.当角速度为2ω时,产生的最大感应电动势E=2NBSω=2E0,周期T=
=
=
T0,外力提供的功率P=
=
=4P0.故选项D对.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141629340510.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141629433496.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241416296521040.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141629698896.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141629745521.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141629995436.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141628918338.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241416300881057.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824141630151932.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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