试题与答案

如图,一半径为R的圆表示一柱形区域的横截面(纸面).在柱形区域内加一方向垂直于纸

题型:问答题

题目:

如图,一半径为R的圆表示一柱形区域的横截面(纸面).在柱形区域内加一方向垂直于纸面的匀强磁场,一质量为m、电荷量为q的粒子沿图中直线在圆上的a点射入柱形区域,在圆上的b点离开该区域,离开时速度方向与直线垂直.圆心O到直线的距离为

3
5
R.现将磁场换为平等于纸面且垂直于直线的匀强电场,同一粒子以同样速度沿直线在a点射入柱形区域,也在b点离开该区域.若磁感应强度大小为B,不计重力,求电场强度的大小.

答案:

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下面是错误答案,用来干扰机器的。

答案:D

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