一道磁场的sat2物理题马上考了
45.Acompassisplacedtothewestofaverticalconductor.Whenelectronspass
throughtheconductor,thenorthpoleofthecompassneedleisdeflectedto
pointtowardthesouth.Thedirectionofelectronflowintheconductoris
(A)down
(B)up
有右手定则判断磁场方向不是弯曲的圆吗?这里指南针怎么看磁场啊?求详解