B=4B1 sin0 44I12 4x2+12)N4x2+212 4×4×10-7×5×(8×1022 π(0.04+0.0064)(0.04+0.128)1/2 =4.8×106T 结東目录=4.8×10-6 T = 4×4π×10-7×5×(8×10-2) 2 π(0.04+0.0064)(0.04+0.128)1/2 B = 4B1 sinq 2 4 x 2 4 + l 2 m I π 0 l ( ) x 2 2 4 + l 2 = 结束 目录