物理問題-有關電流流量

根據法拉第電動感應定律，

感應電動勢，ε = -dΦ/dt = -BdA/dt

Φ是通磁量

dA/dt是銅線劃過磁場面積的速度

dA/dt =(1)(1) = 1 m2s-1

所以，ε = -(20 X 10-6)(1) =20 nV

銅的電阻率，ρ = 1.72 X 10-8 Ωm

根據R = ρL / A

電阻，R = (1.72 X 10-8)(1)/ π(0.5 X 10-3/2)2 = 0.0876 Ω

所以感應電流值，I = ε / R = (20 X 10-6)/ 0.0876 = 2.28 X 10-4 A

If there is a copper wire alone, there would not be a complete circuit. No current will be flowing though there is an induced emf.


2009-08-23 10:28:42 補充：
You can't assume that it is a complete circuit if that is not given in the question. In case it has been given, why not spell it out clearly? This saves the time of letting readers to guess.