Lenz Law: Which Capacitor Plate Becomes Positive?

In summary, a circuit with a resistor and uncharged capacitor is subjected to a uniform magnetic field (B) pointing into the plane of the circuit. If the magnetic field increases in magnitude over time, the top plate of the capacitor becomes positively charged due to the flow of electrons into it. The hand rule can be used to determine the direction of the current, and the capacitor can be ignored as it acts like a direct connection while uncharged.
  • #1
starless.aeon
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A circuit contains a resistor and an uncharged capacitor. Pointing into the plane of the circuit is a uniform magnetic field (B). If the magnetic field increases in magnitude with time, which plate of the capacitor (top or bottom) becomes positively charged?



I don't understand how the hand rules play into this question, because of the capacitor. And I don't understand how I'm supposed to figure out which plate is positive and which is negative. Please help me out?



Thanks in advance, guys. :shy:
 
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  • #2
A capacitor acts like a direct connection when it is uncharged, so ignore it while you use the hand rule to determine the direction of the current. Charge doesn't actually pass through a capacitor, so if positive current flows into a capacitor, it will charge that side of the capacitor positively.
 
  • #3
OH. It makes this question so much easier now, thanks. bundles.

I've come to determine my upper plate is negative cause the electrons flow into it.

again, thanks so much.
 

1. What is Lenz Law?

Lenz Law is a fundamental law of electromagnetism that states that the direction of an induced current in a conductor will always be such that it opposes the change that caused it.

2. How does Lenz Law apply to capacitors?

In capacitors, Lenz Law applies to the direction of the induced current in the metal plates as the electric field between them changes. The direction of the induced current will be opposite to the direction of the change in the electric field.

3. What is the relationship between Lenz Law and Faraday's Law?

Lenz Law is a consequence of Faraday's Law of electromagnetic induction, which states that a changing magnetic field will induce an electromotive force (EMF) in a conductor. Lenz Law specifies the direction of the induced EMF.

4. Which capacitor plate becomes positive according to Lenz Law?

According to Lenz Law, the capacitor plate that becomes positive will be the one that experiences a decrease in the electric field. This is because the induced current will flow in the direction that opposes the change in the electric field.

5. How does Lenz Law affect the energy storage in a capacitor?

Lenz Law does not directly affect the energy storage in a capacitor. However, it does influence the direction of the induced current, which can affect the rate at which the capacitor charges or discharges and therefore impact the amount of energy stored in the capacitor.

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