题目内容
将一根长为L的直导线,由中点折成直角形放在磁感应强度为B的匀强磁场中,导线所在平面与磁感线垂直.当导线中通以电流I后,磁场对导线作用力大小为( )
A.IBL | B.![]() | C.![]() | D.![]() |
D
解法一:将通电直导线从中点折成直角,由左手定则分别判断出两个
导线的F安的方向,如图所示.这两个力的方向垂直,大小均为F安′=
,磁场对整个通电导线的作用力为两段导线所受F安的合力,即F安=2F安′=
;解法二:如图,折线abc受力等效于a和c连线受力,由几何知识可知
,则整个通电导线所受F安=IB·
,故D选项正确.
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241209414401917.jpg)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120941347258.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120941300330.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120941331376.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120941409369.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/20140824120941425501.gif)
![](http://thumb.1010pic.com/pic2/upload/papers/20140824/201408241209414401917.jpg)
![](http://thumb2018.1010pic.com/images/loading.gif)
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