不如用另一個想法
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係銅片個case,如果唔考慮D 復雜 quantum野,我地可以當銅片入面有個 "sea" of free electron(d 銅既 nucleus係個 "sea" of free electron入面)。咁當個 銅片轉個陣,D free electron就會 experience Lorentz force(F= qE + v x B),因為 銅入面D electron 唔係同nucleus有好強既 bonding,所以D electron就會因為Lorentz force而走到去碟邊
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不過如果水依個 case應該點諗
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水係 molecules我嚟,係水入面D咩野野動左
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(油+鐵粉我都Ok明。因為可以係鐵粉D charge 因為 Lorentz force走埋左一邊,然後鐵粉 D E Field再induce油出 E Field
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)