1. Limited time only! Sign up for a free 30min personal tutor trial with Chegg Tutors
    Dismiss Notice
Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Zero electric potential proof

  1. Dec 28, 2013 #1
    how can I prove that no current would flow in a wire connected between two wires of equal potential. For an example a resistor of 2 ohms carrying a current of 3 Amp and a resistor of 3 ohms carrying a current of 2 Amp, and a wire "A" is connected between them. Obviously, the potential difference between the two wires is 6-6=0 but what is the explanation for the fact that no current will flow in Wire "A" I know that only as a fact but I can find an obvious clear explanation.
     
    Last edited: Dec 28, 2013
  2. jcsd
  3. Dec 28, 2013 #2
    Kirchoff's current law is violated
     
  4. Dec 28, 2013 #3
    Hey also, ypu are talking about potential difference and not potential.
     
  5. Dec 28, 2013 #4

    Please could you explain it in detail
     
  6. Dec 28, 2013 #5
    if you connect something , like a wire between two points, wires whatever which both have the same potential then no current flows because they both are at the same level of voltage.

    Just like water needs a slope or a decrease in height above sea level to flow.If you would have just a perfectly flat piece of land no rivers could flow.
     
  7. Dec 28, 2013 #6

    Can you explain what is meant by the game the same potential ?
     
  8. Dec 28, 2013 #7
  9. Dec 28, 2013 #8
    well a potential forms when there is some excess of charge (like positive or negative) if both are the same then there is no potential the material or whatever we say is neutral.
    So if you have more positive charge on one side of the battery and more negative on the other or just ground in other cases ,then we say we have a potential difference and that can do work because the charges which are more at one point want to flow to the other point to equal out , while they flow , we say energy is being transfered and work can be done using that energy.

    voltage or volts is just a measurement unit in which we measure the potential difference.
     
  10. Dec 28, 2013 #9
    I got the part that electrons flow from high charge to low one
    But a wire of resistance 3 ohms carrying a current of intensity 2 Amperes connected to another wire of resistance 2 ohms carrying a current of 3 amperes No current will flow between them although their intensities are different and quantity of electricity is different so there should be tendency for electrons to flow from high charge to low charge
     
  11. Dec 28, 2013 #10
    well there is no high charge or low charge , charge is charge , there is more charge per given area or less charge per given are or no charge at all which means that the material is neutral it has an equal number of + and - charges in it.

    about the resistors you mentioned remember that current or amperage is just another word like volts and voltage.the word itself means nothing you have to understand the meaning behind the word.

    amperage or amps is the measure of how much charge flows in a given place at a given amount of time (1 second)
    so you take a place in a wire and place an ampmeter in series with that wire , now close whatever circit you have there and see how many amps flows (charge flow) through that wire.
    BUT if you have two wires and both wires are at the same potential !!! this is the important part , then no current flows , yes it is correct that a resistor with less resistance will have a higher current , that is correct but a resistor can only have a current through it if it is either in a circuit (part of a circuit) or if it is in series with a wire which has a potential difference across it , like putting that resistor across the battery terminals you were talking earlier.
    if there is no circuit and no potential difference no amps( charge) will flow through the resistor so you can connect it as you wish nothing will happen.
     
  12. Dec 28, 2013 #11
    ImageUploadedByPhysics Forums1388252236.587838.jpg I mean that the amount of charge at A is more that at B, Although no current will flow through R???
     
  13. Dec 28, 2013 #12

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    This is not a clear description of a circuit, and without additional information about the circuit it is impossible to tell if there will be a current flow.
    If you connect two resistors in parallel, then different currents can flow through them. That should not be surprising.

    Edit: I wrote my post before I saw your last post.
    A and B cannot be open ends, the current will flow to something else, so no charge is accumulating anywhere. Current is "charge per time" - and everything that flows in always flows out again (to a very good approximation).
     
  14. Dec 28, 2013 #13

    Check the figure that I posted before your post
     
  15. Dec 28, 2013 #14

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    You posted while I was already writing my post. See my edit in post 12.
     
  16. Dec 28, 2013 #15

    I don't understand what do you mean? I just want to know if there is going to be a current through R or not considering that the amount of charge at A is more than That at B
     
  17. Dec 28, 2013 #16

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    I changed my previous post (you can change posts after you posted them, see the "edit" button in your posts).
    That depends on the remaining circuit, especially the connections at A and B.
    There are no charges hanging around, neither at A nor at B.
     
  18. Dec 28, 2013 #17
    I think what you say is "obvious" is the answer to a question. I doubt the question was "prove that no current would flow in a wire connected between two wires of equal potential". That's obvious.
     
  19. Dec 28, 2013 #18
    ImageUploadedByPhysics Forums1388254032.592837.jpg thats the rest of the circuit
     
  20. Dec 28, 2013 #19

    mfb

    User Avatar
    2016 Award

    Staff: Mentor

    Okay. The 4Ohm-resistor has 3A as well (so it is between a voltage of 12V), and the 6Ohm-resistor has 2A (so it is between a voltage of 12V -> matches). As you can see, all electrons that come through the upper left resistor can go through the upper right resistor, and the same happens at the lower side. There is no current in the vertical line.

    If you change one of the resistors, this changes.
     
  21. Dec 28, 2013 #20

    I have begun to really understand, but you are saying that the amount of charge at A is equal to that at B, then how are the intensities different ?
     
Know someone interested in this topic? Share this thread via Reddit, Google+, Twitter, or Facebook




Similar Discussions: Zero electric potential proof
  1. Electric Potential (Replies: 2)

  2. Zero Potential Energy (Replies: 5)

Loading...