Charge Conservation: A+2 & B+7 → A+5 & B+5

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Discussion Overview

The discussion revolves around the conservation of charge when two conductors, A and B, with initial charges of +2 and +7, respectively, touch and then separate. Participants explore the implications of charge quantization and the distribution of charge between the conductors after contact.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant asserts that when conductors A and B touch, charge will flow until they reach equal charges, leading to a charge of +5 on each in the case of +2 and +8 charges.
  • Another participant questions whether the charges are being discussed in units of elementary charge (e), suggesting that the scenario may not accurately represent macroscopic conductors.
  • A participant clarifies that the net charge for A and B should consider all charges in the system, including electrons, and that the charge distribution will shift to accommodate any imbalance.
  • One participant proposes that if there is an odd number of electrons and an even number of protons, the charge distribution will not be equal, leading to one conductor having a charge of 4 electrons and the other 5, influenced by thermal noise.

Areas of Agreement / Disagreement

Participants express differing views on the implications of charge quantization and the behavior of charges in macroscopic systems. There is no consensus on the final charge distribution after the conductors touch.

Contextual Notes

Participants highlight the importance of considering the total charge, including electrons, and the implications of charge quantization. The discussion remains unresolved regarding the exact charge distribution after the conductors touch.

Ed Quanta
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Now suppose we have two conductors A and B. A has a charge of +2 and B has a charge of +8. If we let the two conductors touch and then separate them, each will have a charge of +5. This is because charge is conserved and will flow between the two conductors until each have equal charges.

Ok, so how would this change if instead of B having a charge of +8, it had an initial charge of +7. Now if let the conductors touch and separate them, each of them cannot have a charge of +4.5 because charge is quantized and there is no such thing as half of an electron. So what would happen? What would be the charge on each conductor?
 
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When you say a charge of do you mean in units of e?

This is confusing. If you are talking in units of e then you describing basically two nuclei of Z=2 and 8 "touching". This is nothing like touching 2 macroscopic objects of some charge.

can you explain a bit more what you mean?
 
Wait, sorry do you mean a macroscopic conductor with net charge of +2e and +8e
 
Yeah
 
Well, the net charge for A and B in isolation would be +8e and +7e. This is the sum over ALL the charges of the system where all the positive nuclei are canceled by all but 8 and 7 electrons.

So you are not dealing with an 8e and 7e system, you have to take into account all the electrons.

When A and B approach in the first case as you say, the electrons will equilise the charge on each body. In the second case where there is an odd number of electrons and and even number of protons for the whole system (A+B) then the charge distribution of A and B will shift to accommodate the charge imbalance.
 
There would be a charge of 4 electrons on one and a charge of 5 on the other. Assuming that your spheres were absolutely perfect identical spheres then there would be a 50/50 chance of each having the "extra" charge. It would be determined simply by thermal noise.
 

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