电磁感应1qqP° q qy w (Biot-Savart Law) w°w (Ampere‘s Law) q§ w° -°¨§Jw(Ampere-Maxwell Law) ° q q§Pq¤q° kw (Faraday’s Law) ° ¨ § J ¤ è { (Maxwell’s Equations)--- n ¤ § ¤¤¤jz¨t ]¤ZqP¤@ -1qqy(Biot-Savart Law) w°w (Ampere‘s Law)ww (Biot-Savart Law) êiH±o¨ìdB = 0 ids × r 4π r 3∈dB =04πids sin θ r20=4π× 10-7 Tm/A ≈ 1.26× 10-6 Tm/A permeability constant v `NG dB⊥ds, r Mw¨w§¤ dE = 1 dq 4πε0 r 2 dE = 1 dq r 4πε 0 r3ΜΖ∞↑Χ ¤¤¤jz¨t ]¤Z qP¤@ -21quqyy¨¤§B=dB = 0 Ids sin θ 4π r2∞0 I 2πaB = 2 ∫0 dB = r = s 2 + a2 , B = 2 ∫ dB =0 ∞ 0I 2π∫∞0sin θds r2 a s + a22sin θ = sin(π θ) = 0 I 2π∫ (s0∞ads2+a2)3/ 2I s = 0 2 2 2πa s +a() I = 0 1/ 2 0 2πa ∞¤¤¤jz¨t ]¤ZqP¤@ -3qn¤-pGs = a tan θ,(s+ a……