题目内容
如图2所示,n=50匝的圆形线圈M,它的两端点a、b与内阻很大的电压表相连,线圈中磁通量的变化规律如图所示,则ab两点的电势高低与电压表的读数为:
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241402259245296.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241402259245296.jpg)
A.![]() ![]() ![]() ![]() | B.![]() ![]() ![]() ![]() |
C.![]() ![]() ![]() ![]() | D.![]() ![]() ![]() ![]() |
B
磁通量增大,产生的感应电流的磁场向外,由右手螺旋定则判断电流在圆环上为逆时针,在电源内部电流由负极流向正极,所以a点相当于电源正极,![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140226018324.png)
>![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140226018324.png)
,由
可知电源电动势为100V,B对;
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140226018324.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140226080252.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140226018324.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140226252254.png)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824140228124756.png)
![](http://thumb2018.1010pic.com/images/loading.gif)
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