What is the direction of the electric field inside a battery?

  • #1
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Outside the battery, in the conductor it is in the direction of conventional current. But what about inside?

Since magnetism and electricity are related, and magnetic field inside a magnet is from South to North (outside it is North to South), i doubted for any correspondence.
 

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  • #2
BvU
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Hello Top, :welcome:

Here at PF we encourage prior research by posters: it's too hard and time consuming (and ineffective) for us to re-write textbooks (or even chapters thereof). Much easier :smile: to answer specific questions about details and thus complement those textbooks and help posters to make their next step (something that is difficult for a book).

So in your case some googling for orientation would be good for you ( and for us :wink: ). Start with 'battery chemical process' or something like that.

And, to boot, a bit of advice: when analyzing electric circuits, don't worry about what is going on inside a battery :rolleyes: or a power supply, for that matter.
 
  • #3
sophiecentaur
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don't worry about what is going on inside a battery :rolleyes: or a power supply, for that matter.
. . . . or even what is going on inside a theoretical source of emf. Consider the stator of an alternator. The emf's induced in each mm length of the wire is such as to cause a current to flow into the load. If you really have to, you can consider the local fields to be in the direction of the current. The Potential Change all the way round the circuit is Zero.
Kirchoff's Second Law talks in terms of Energy and not Fields but it tells the whole story about conservation of Energy.
 
  • #5
BvU
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Looks messy to me. FInd a good electrochemistry textbook if you want to do electrochemistry. Heed our advice for electric circuit analysis and electronics.
 
  • #6
sophiecentaur
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Looks messy to me. FInd a good electrochemistry textbook if you want to do electrochemistry. Heed our advice for electric circuit analysis and electronics.
I can't help feeling that this approach is overkill for the question and the OP.
Whatever the actual mechanism that produces a flow of charge out of the + terminal and into the - terminal, the battery (or any other power source) has to have internal electric fields which are the only way to make electrons flow out of the - terminal. No nuts and bolts explanation is needed to be able to make that assertion.
OF course, we can take it from there as far as we like and, in the case of a chemical cell, there have to be reactions that force electrons to turn up in the material of the -ve plate (internal Electric Fields). If the electrons have no external path available (nothing connected) then the resulting field inhibits further chemical reactions because the energy is not high enough.
 
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  • #7
BvU
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Seems to me our problem is that we don't know what is the specific interest of Toppy. Can you help us with that, @Topsykret ?
 
  • #9
sophiecentaur
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I think you could sort this out in your own mind if you didn't feel it necessary to reconcile (to the letter) a number of statements here and elsewhere that may not have been written in the 'best way'. Just go back to basics and follow the 'rules' about the relationship between PD and Current and keep Kirchoff's Laws in mind. The thread about diodes may not have stated the obvious fact that you can't get current flowing from the diode into the source (battery) against the sense of the battery PD. A reverse biassed diode will not pass current because the charges inside it have been displaced until the microscopic fields due to charge displacement balance the applied field. Inside a battery that's connected to a completed circuit. The charges are constantly being displaced by the chemical reactions whilst there is a path for the current to flow. The difference between a battery and a diode is that one is a source of energy and the other isn't - sorry to state the obvious but sometimes it helps.
PS You can be fairly that there is nothing 'wrong' with the theory so just re-run it past yourself a few times whilst thinking slightly differently and it will probably become clear. Hyperphysics is fairly bomb-proof in its wording - try this link about diodes and it makes sense (to me, at least).
 

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