問題詳情
4.Assume that a long solenoid of radius R with n turns of thin wires per unit length is carrying a steady current /，and its axis of symmetry is along the z-direction.
【題組】(a)Justify that the magnetic field (whenever nonzero) is in the z-direction.
參考答案
答案：A
難度：非常簡單0.959596
統計：A(285),B(0),C(9),D(1),E(0)