题目内容
如图所示,矩形线圈的匝数为N,面积为S,内阻为r,绕OO′轴以角速度ω做匀速转动.在它从如图所示的位置转过90°的过程中,下列说法正确的是( )
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241140353922163.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241140353922163.jpg)
A.通过电阻的电荷量为![]() |
B.通过电阻的电荷量为![]() |
C.外力所做的功为![]() |
D.外力所做的功为![]() |
BD
线圈从图示位置转过90°的过程中,感应电动势的平均值
=N
=
,通过R的电荷量q=IΔt=
Δt=
,故A项错B项对.线圈转动过程中产生的感应电动势的最大值Em=NBSω,有效值E=
=
.据闭合电路的欧姆定律I=
=
,据能量守恒,外力所做的功将全部转化为电能,故
W=EIt=
·
·
·
=
,故C项错D项对.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035470207.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035485302.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035501454.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035516409.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035407479.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035548400.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035548516.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035594404.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035594651.gif)
W=EIt=
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035548516.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035594651.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035641372.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035657221.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824114035454691.gif)
![](http://thumb2018.1010pic.com/images/loading.gif)
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