MoIl B1=4x2+24x2+122 sin0=1/2 l/2 x2+12/4 B=4B sine 4I1 1/2 =4×4x+P4x2+12x+P/4 44I12 T4x2+12）4x2+212 结東阑 目录 q q a B 1 l B1 x 2 + l 4 2 = m I 4π 0 l x 2 + l 2 . 2 B = 4B1 sinq = 4 x 2 + l 4 2 m I 4π 0 l x 2 + l 2 . 2 × x 2 + l 4 2 l 2 2 4 x 2 4 + l 2 m I π 0 l ( ) x 2 2 4 + l 2 = sinq l 2 a = = x 2 + l 4 2 l 2 结束 目录