標題: Lenz's law [打印本頁] 作者: 小霞的fans 時間: 6/12/2009 02:34 PM 標題: Lenz's law an induced current always flows to oppose the changewhich startrd it in a magnetic field.
紅字果句唔明 - - " 其實姐係點 .. 個induced current oppose 個magnetic field ?作者: orb 時間: 6/12/2009 05:10 PM 假設一個磁鐵要穿過一個銅線圈
當switch S開左就產生magnetic field作者: 小霞的fans 時間: 7/12/2009 06:11 PM when switch is closed,a magnetic field will be bulit up in the solenoid. there will be an induced current flowing in the aluminium ring.By Lenz's law.the induced current flows in a direction such that it produces an effect to oppose the change. so the end of the ring near the solenoid becomes a south pole.the aluminium ring will move away from the solenod under the action of the replusive force acting on it by the solenoid.
when switch is closed,a magnetic field will be bulit up in the solenoid. so there is change of magnetic field along the solenoid which also affect the aluminium ring there will be an induced current flowing in the aluminium ring due to repulsion which tends to change the magnetic field back to normal By Lenz's law.the induced current flows in a direction such that it produces an effect to oppose the change.
so the end of the ring near the solenoid becomes a south pole.the aluminium ring will move away from the solenod under the action of the replusive force acting on it by the solenoid.
