27. Current enters a circular loop as shown below. At point P, where x = a, the magnetic field has t

問題詳情

27. Current enters a circular loop as shown below. At point P, where x = a, the magnetic field has thevalue

. The value of the magnetic field at x = -a is:

(A)0
(B)

(C)

(D)

(E)

答案：C
難度：計算中-1
書單：沒有書單，新增