問題詳情

45. A uniformly charged insulating rod is bent into the shape of a semicircle as shown on the right. The rod has a total charge Q and the radius of the semicircle is R. What is the magnitude of the electric field at O, the center of the semicircle?


(A)


(B)


(C)


(D)


(E)

參考答案

答案：A

統計：A:0,B:0,C:0,D:0,E:0

難度：計算中