电磁感应 电磁感应定律电动势.自慼与互感暂态过程) dw K do d B·ds E=v×B k E, dl BdS分V×E B at k电磁感应 (电磁感应定律,电动势,自感与互感,暂态过程) s d d B ds dt dt   = − = −   ext K F dl dW E dl dqdt q  + + − −  = = =    E v B k =  E dl B d S E B k k t t      = −    = −        