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How does increased conductivity affect voltage?

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  1. Feb 24, 2016 #1
    If I have a certain circuit set up with a voltage V, then how does increased conductivity in the wire affect the voltage, or does it? I know that increased conductivity affects current, but if Ohm's law is to be true , voltage must increase or resistance must decrease. So which is it? Is voltage affected, or does resistance decrease?
     
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  3. Feb 24, 2016 #2

    phinds

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    This is a bit of a garbled question. Typically, wires are so conductive that increased conductivity won't make any practical difference in a circuit but it will make a very small difference.

    If you have an ideal power source, what would you expect the voltage to do if you increase the conductivity of the wire outside the power source?

    The reason I say the post is garbled is you posit an increase in conductivity and then you ask if the resistance decreases. Do you understand the relationship between "conductivity" and "resistance" ?
     
  4. Feb 24, 2016 #3
    I'm just asking how Ohm's law applies to this scenario. Just assume that the very small difference is significant for arguments sake. So would an increase i conductivity increase current and decrease resistance? Without voltage changing?
     
  5. Feb 24, 2016 #4

    phinds

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    You did not answer either of my questions.
     
  6. Feb 24, 2016 #5
    For the first question, changing conductivity would not change the power supplied as that is a property of the power source itself. And I guess that I don't understand the relationship between conductivity and resistance, hence me asking this question.
     
  7. Feb 24, 2016 #6

    phinds

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    Your first answer is wrong and your second answer is what I expected.

    Taking "conductivity" and "resistance" first, these are just words that express the same thing but inversely. That is conductivity is just the reverse of resistance so if one goes one way the other obviously goes the other way.

    Power out of a source is NOT a property of the source it is a function of what the source is hooked up to (up to the power limits of the source, at which time things do become dependent on both the source and the load).

    You need to draw a simple circuit and ask a specific question about it. If you have a power source and a non-ideal wire hooking it to a single resistor, then if the conductivity of the wire goes up the resistance goes down which means the total resistance that the source is powering goes down (very slightly) so the current goes up.
     
  8. Feb 24, 2016 #7
    Conductivity is the inverse of resistivity. They are properties of materials and not of the circuit.
    Conductance is the inverse of resistance. These are properties of the circuit or elements of the circuit (resistors).

    You cannot "change conductivity in the wire" unless you replace the wire with another, made from a different material.
    Or if you change the temperature of the wire or by some other effects.

    It is not clear what you actually ask. You need to explain more how did you come to this question.
     
  9. Feb 25, 2016 #8

    Drakkith

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    Note that the voltage applied to the circuit as a whole does not change. When you alter the resistance of something in the circuit, it is the current that changes, not the voltage. However, what you may want to look into is the voltage drop across each component. That WILL change.
     
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