Question

大学物理求解第六题

Answer 1

圆电流 I = q ω / (2π) = 2π R λ ω / (2π) = R λ ω
所以
B = μ0 I R^2 / [ 2 (R^2 + y^2)^(3/2)]

= μ0 R^3 λ ω / [ 2 (R^2 + y^2)^(3/2)]
方向向上。