Chapter 27 Electromagnetic Induction and faraday's law 27-1. Induced EMF page629-630 1. Two experiments First experiment D)A current appears only if there is relative motion between the loop and the magnet; the current disappears when the relative motion between them ceases 导体回路和磁铁有相对运动时,回路中就会产生电流.Chapter 27 Electromagnetic Induction and Faraday’s Law 27-1. Induced EMF page629-630 1. Two experiments I N First experiment S 1) A current appears only if there is relative motion between the loop and the magnet; the current disappears when the relative motion between them ceases. 导体回路和磁铁有相对运动时, 回路中就会产生电流