唔該幫我問問kenchan (about磁)

harry sze

2007-12-06 6:13 am

唔知點解我上唔到佢個網..

我想問electromagnetic induction...

當個magnet(with north pole) is pushed into a coil個陣...

咁個coil就用返north pole頂住佢...想令到magnet loss K.E.

而coil gian P.E. 而產生induced e.m.f.

咁即係個magnet進入and穿出coil時都會減速??

咁如果個magnet keeping a constant velocity 穿過個coil..

咁有冇induced e.m.f.???

但個magnet冇loss K.E.??

咁coil點得P.E.???

唔該晒

回答 (1)

Carson

2007-12-07 6:37 pm

✔ 最佳答案

1.
咁即係個magnet進入and穿出coil時都會減速??
如果你無繼續比動力塊磁石，由於磁石loss kinetic energy to the coil，K.E. 減少，速度必定減少
如果你有繼續比動力塊磁石，由於磁石loss kinetic energy to the coil & gain energy from you，K.E. 可以不減少，由此速度固定

2.
咁如果個magnet keeping a constant velocity 穿過個coil..
咁有冇induced e.m.f.???
Coil gain energy from 磁石，能量轉變成induced e.m.f.

3.
但個magnet冇loss K.E.??
磁石不是無loss K.E.，只是loss kinetic energy to the coil & gain energy from you，於是K.E. 可以不減少，由此速度固定

4.
咁coil點得P.E.???
Coil gain energy from 磁石，能量轉變成induced e.m.f.
希望解答到你 ^^

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