Charge reconfiguration on wires connnected to capacitor

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Discussion Overview

The discussion centers on the effects of introducing a conductor slab between the plates of a charged capacitor connected to ideal conducting wire strips. Participants explore the implications for capacitance, potential difference, and surface charge distribution on the wires.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant notes that introducing a conductor slab increases the capacitance and reduces the potential difference between the capacitor plates, suggesting that this can be explained by integrating the electric field between the plates.
  • Another participant proposes that the surface charge configuration of the wire strips must change to account for the reduced potential difference, speculating that the surface charges on the wires should decrease.
  • Some participants argue that the changes in surface charge on the wires are negligible in most realistic setups, indicating that the capacitor plates may experience a slight increase in surface charge and electric field strength.
  • A later reply suggests modeling the system with two capacitors in parallel, implying that the introduction of the conductor slab alters the circuit configuration.
  • One participant questions the overall impact on the circuit, stating that the changes should not significantly affect the rest of the circuit.

Areas of Agreement / Disagreement

Participants express differing views on the implications of introducing the conductor slab, particularly regarding the changes in surface charge on the wires and the overall effect on the circuit. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants have not reached a consensus on the mechanisms behind charge reconfiguration or the implications for potential difference and circuit behavior. Assumptions regarding the negligible effects of surface charge changes are also debated.

Jyothish
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Consider a capacitor which is charged to a certain voltage 'V' and having a total charge 'q' in it.The leads of the capacitor are connected to ideal conducting wire strips.Now if I introduce one conductor slab between plates of the capacitor, without touching the plates,as we know from basic electrostatics that the resultant capacitance increases.This means that ,for the same charge, potential difference between plates of the capacitor is reduced.This is easily explainable if we consider the the electric field 'E' between plates and integrate it between plate separation.

However, please consider the following
1) Since the wire strips are connected to plates, each wire strip will have the same potential as that of plate to which it is connected

2)Potential difference between plates must be equal to the potential difference between wire strips

3)Potential difference is independent of path.Hence if we integrate the electric field 'E' between the wire strips, by following a path without going through the capacitor, I should get the same potential difference.

But ,when we introduce the conductor slab, to get a reduced potential difference(by integrating ' E' without going through capacitor) between wire strips, the surface charge configuration of wire strips must be altered.In this case surface charges should be reduced,I guess

I am not getting, which mechanism does this re-configuration of charges.And also, where is the excess charge going to

If my assumption that the surface charge on the wires are reduced is incorrect,how we will get a reduced potential difference when 'E' is integrated over a path(not through capacitor) between wire strips.
 
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Jyothish said:
But ,when we introduce the conductor slab, to get a reduced potential difference(by integrating ' E' without going through capacitor) between wire strips, the surface charge configuration of wire strips must be altered.In this case surface charges should be reduced,I guess
Right. This is completely negligible for most realistic setups. The capacitor plates will get a tiny increase in surface charges and electric field strength.

You can model this system with two capacitors in parallel, where you increase the capacitance of the significantly larger one.
 
thank you for the reply
 
Jyothish said:
Now if I introduce one conductor slab between plates of the capacitor, without touching the plates

What you do is equivalent to changing the circuit to having two capacitors in series, with the same resulting capacitance as the original capacitor. I cannot quite see what difference it should make to the rest of the circuit.
 

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