電磁學-electromagnetism

想問問有關right-hand rule/left-hand rule/right hand grip rule
佢地個原理係咩?

right hand rule/left hand rule relates the directions of force, magnetic field lines and current.

The right hand grip rule gives the direction of magnetic field around a current carrying straight conductor.

Notcie that these three are rules only, not a theory or a law.
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點解current同magnetic field成直角會有force??

This is because of the interaction between the magnetic field generated by the current and the applied magnetic field.

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同埋d voltage/current係點induce....?

By Faraday's law, whenever there is a change of magnetic flux, emf will be induced.
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係有induce current先有induced voltage的嗎??
No. The induced current is driven by the induced voltage.
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沒有induced current是不是可以有induced voltage.?
Yes. In an open circuit, any induced voltage would not cause current to flow.