Change in potential of terminals of batteries

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Discussion Overview

The discussion revolves around the potential difference between the terminals of batteries when connected together, specifically addressing what happens to the potential of the terminals and the individual potential differences of the batteries involved. The scope includes conceptual understanding and technical reasoning related to electrical circuits.

Discussion Character

  • Conceptual clarification
  • Debate/contested
  • Technical explanation

Main Points Raised

  • Some participants propose that when the positive terminal of one battery is connected to the negative terminal of another, the connected terminals achieve the same potential, leading to questions about the individual potential differences of the batteries.
  • Others argue that there is zero potential between the negative terminal of one battery and the positive terminal of another without a complete circuit, implying that nothing occurs in this scenario.
  • A participant clarifies that connecting points with low or zero resistance results in them being at the same potential, but each battery continues to present the same potential difference across its terminals as before.
  • Another participant questions how the individual potential drops can remain the same if the connected terminals achieve a common potential that differs from their original states.
  • One participant explains that a battery's terminal has a defined potential only when part of a complete circuit, emphasizing that electrons must drift into the negative terminal for the chemical reaction to maintain potential.
  • A specific example is provided involving two 12V batteries connected in series, suggesting that the potential difference between the other terminals would be 24V, depending on the reference point chosen for 0V.
  • Another participant notes that the 'original potential' of a battery's terminals is undefined when isolated, stating that only the potential difference across its terminals can be known.

Areas of Agreement / Disagreement

Participants express differing views on the implications of connecting battery terminals, with some asserting that potential differences remain unchanged while others question this assertion. The discussion remains unresolved regarding the relationship between common potential and individual potential drops.

Contextual Notes

Limitations include the undefined nature of a battery's original potential when isolated and the dependence on circuit completion for meaningful potential measurements.

Vishwas D
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I know there will be potential difference between the terminals of a battery. But when the positive terminal of a battery is connected to the negative terminal of another, will both of the connected terminals achieve the same potential? If so, what happens to the individual potential differences of the batteries?
 
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There is zero potential between the negative of one battery and the positive of another. Absolutely nothing occurs without a circuit between the remaining terminals.
 
Vishwas D said:
I know there will be potential difference between the terminals of a battery. But when the positive terminal of a battery is connected to the negative terminal of another, will both of the connected terminals achieve the same potential? If so, what happens to the individual potential differences of the batteries?
Hi Vishwas D.
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When points are connected together by wire having low or zero resistance, they become the same potential. There can consequently not exist any potential difference between those connected points.

When connected in series as you describe, each individual cell continues to present exactly the same potential difference between its two terminals as before; not a thing has changed as far as any of the individual cells is concerned.
 
But when the connected terminals achieve the same potential, The common potential of those terminals will be different from the original right? Then how do the individual potential drops remain same?
 
A single battery terminal has 0VDC potential. You can connect + on one battery and + on another and it will not short the batteries unless you connect the - terminals. A battery is not a storehouse of electrons that flow like water from a hose, electrons have to drift into the negative terminal for the chemical reaction inside the battery to maintain the potential, which can only be realized in a complete circuit.
 
Consider two 12V batteries with the +ve of one connected to the -ve of the other. The potential difference between the other terminals will be 24V.

It is possible to define any of the terminals as a reference 0V. Depending on which you choose you can generate...

0 +12 +24
-12 0 +12
-24 -12 0
 
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Vishwas D said:
But when the connected terminals achieve the same potential, The common potential of those terminals will be different from the original right? Then how do the individual potential drops remain same?
The 'original potential' of a battery's terminals is unknown/undefined/unspecified if it is not connected to anything. All you can say about an isolated battery sitting by itself is that there exists a known potential difference across its terminals.
 
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