• 2021-04-14
    如图,两根直导线ab和cd沿半径方向被接到一个截面处处相等的铁环上,稳恒电流I从a端流入而从d端流出,则磁感强度沿图中闭合路径L的积分等于(  )http://image.zhihuishu.com/zhs/onlineexam/ueditor/201904/2e3ddc6fc011405a84a440c9a9a7517c.png