22.4
유도에 의한 도체 충전
지구는 전기가 잘 통하는 전도체이며, 전하의 무한한 원천 또는 흡수원으로 간주될 수 있을 정도로 매우 큽니다. 어떤 문제에 대해서도 쉽게 요금을 교환할 수 있습니다.
일반적으로 금속과 같은 전도체는 초과 전하가 존재하는 것을 허용하지 않습니다. 예를 들어, 금속을 지구…
플라스틱 막대를 털에 문질러 음전을 충전하십시오.
절연 플라스틱 스탠드로 지지되는 전도성 금속 구를 예로 들어 보겠습니다.
하전된 막대가 중성구에 가까워지면 구 내부의 자유 전자가 중성구에서 밀
려납니다.더 많은 자유 전자가 움직이려고 하면 이미 움직인 전자에 의해서도 반발됩니다. 전자는 자유 전자에 알짜 힘이 없도록 분포합니다.
도체의 맨 끝에 더 많은 자유 전자가 축적되어 더 가까운 끝이 순 양전하를 띱니다. 두 극은 반대 방향으로 충전되거나 분극됩니다. 이러한 전하 분포를 쌍극자라고 합니다.
구가 다른 금속 와이어를 통해 지구에 연결되면 자유 전자는 지구로 이동합니다. 와이어가 제거되면 구는 순 양전하를 전달합니다. 이 과정을 인덕션(induction)이라고 합니다.
음전하를 띤 플라스틱 막대는 전하를 잃거나 얻지 않습니다. 유도는 도체와 지구 사이의 전하 교환을 초래합니다.
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Q1: What happens to free electrons when a charged rod approaches a neutral conductor?
Free electrons inside the conductor are repelled away from the charged rod. As more electrons move, they repel others already displaced, creating a distribution where no electron experiences net force. This redistribution leaves the end closer to the rod positively charged and the far end negatively charged, establishing an electric dipole.
Q2: How does grounding enable a conductor to become permanently charged by induction?
When a polarized conductor is grounded via a metallic wire, free electrons flow to or from Earth, which acts as an infinite source or sink of charge. After removing the wire, the conductor retains a net charge opposite to the inducing charge. This permanent charge transfer distinguishes induction from temporary polarization.
Q3: Why is the charge distribution on an induced conductor called a dipole?
A dipole consists of two oppositely charged poles. During induction, the conductor develops a positive charge at one end and negative charge at the other, creating this two-pole configuration. Although the conductor has no net charge initially, the spatial separation of opposite charges defines the dipole structure.
Q4: What role does Earth play in the induction charging process?
Earth is a good conductor and effectively an infinite source or sink of charges due to its size. When a conductor is grounded, Earth exchanges charges with it, allowing excess electrons to flow away or additional electrons to arrive. This charge exchange is essential for converting temporary polarization into permanent net charge on the conductor.
Q5: Does the inducing charged object lose charge during the induction process?
No, the inducing charged object does not lose or gain any charge during induction. The negatively charged rod, for example, remains negatively charged throughout. Induction involves only charge redistribution within the conductor and charge exchange between the conductor and Earth, not transfer from the inducing object.
Q6: How does polarization differ from permanent charging in conductors?
Polarization occurs when a charged object redistributes free electrons in a nearby conductor without grounding, creating temporary opposite charges at each end. Permanent charging requires grounding, which allows charge to flow to or from Earth. Once the inducing object is removed, polarization disappears, but permanent charge remains on the grounded conductor.
Q7: Why do free electrons in a conductor reach an equilibrium distribution during induction?
Free electrons move until they reach a configuration where no electron experiences net attractive or repulsive force. Initially, electrons are attracted toward the positive inducing object, but as they accumulate, they repel incoming electrons. Equilibrium is reached when these opposing forces balance, stabilizing the charge distribution across the conductor.