How does current affect electric potential?

In summary: Well, first of all, Ohm's Law is a laws of physics, so it's reasonable to assume that it would be followed in this situation. Additionally, the potential difference between the two regions should decrease as the amount of charge flowing between them decreases- this is what's predicted by the equation V=Vo e^(-t/CR).
  • #1
Apteronotus
202
0
Suppose you have an two objects A and B having different potentials [tex]\phi_A, \phi_B[/tex] and voltage [tex]V=\phi_A- \phi_B[/tex].

Suppose you allow current to flow from one object to another for some period of time according to Ohm's Law (V=IR)
Now what is the new value of the voltage?

thanks
 
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  • #2
That depends on the rate of electrochemical reaction in the cell
 
  • #3
What are the objects A and B?
As you have defined V as the pd between the two objects, then it is perfectly feasible that the flow of charge is such that the pd between A and B becomes zero after a time t.
I think you need to be more specific in the question formulation.
Are A and B capacitors? Or to be treated as such?
 
  • #4
The objects represent two regions of a biological cell. Current in the form of ions is allowed to flow from one region to the other. Obviously when this current is allowed to flow, the potential difference between the two regions should decrease.

I was wondering if there are any equations which can describe this relation.

Stonebridge, you are right. If enough time is allowed to pass, then the potential difference would become zero.
 
  • #5
I know nothing about cell biology! I'm wondering, though, if it's asking a little too much to assume Ohm's Law is obeyed. Without that, it's not possible to quantify the current flow. And it's this current (I=V/R) which determines the rate at which the charge flows from from A to B.
Additionally, there is the relationship between the potential at A and B and the amount of charge localised at those points. (That's why I asked about capacitors).
In physics there is a formula for the discharge of a capacitor through a resistor.
V=Vo e^(-t/CR)
where Vo is initial potential difference, C is capacitance, R is resistance of circuit, t is time and V the pd across the capacitor at that time.
However, using something like this formula would be making a lot of assumptions about the way the cell behaves. What is R? What would C represent etc etc? I doubt it would work!
Maybe someone else with more knowledge of cell biology would like to try?
 
  • #6
An exact formula would be pretty complicated, I'm sure (I don't know anything about cell biology either), but I would think that whatever it is, it'd still fit the general form of a decreasing curve that asymptotically approaches V=0. I doubt that the innards of a cell have complex electrical structures like transistors or diodes in them :wink: I wouldn't be that surprised if the exponential form
[tex]V = V_0 e^{-t/\tau}[/tex]
turned out to be a pretty decent approximation, for some value of [itex]\tau[/itex] which you'd probably have to determine empirically.
 
  • #7
diazona said:
[tex]V = V_0 e^{-t/\tau}[/tex]

How did you guess that?
 

1. How does current affect electric potential?

The electric potential difference, or voltage, is directly proportional to the current in a circuit. This means that as the current increases, the electric potential also increases. This can be seen through Ohm's Law, which states that V=IR, where V is voltage, I is current, and R is resistance. Therefore, if the current increases, the voltage must also increase to maintain a constant resistance.

2. What is the relationship between current and electric potential?

The relationship between current and electric potential can also be described by the equation P=IV, where P is power, I is current, and V is voltage. This shows that as the current increases, the power also increases, which in turn increases the electric potential. Additionally, an increase in current can also lead to an increase in the rate of energy transfer, or electrical power.

3. How does the direction of current flow affect electric potential?

The direction of current flow does not affect the electric potential, as it is a scalar quantity. This means that it is only dependent on the magnitude of the current, not its direction. However, the direction of current flow can affect the direction of the electric field, which is responsible for creating the potential difference.

4. Can current affect the resistance in a circuit?

Yes, the current in a circuit can affect the resistance. As mentioned before, the voltage in a circuit is directly proportional to the current. This means that if the current increases, the voltage must also increase to maintain a constant resistance. On the other hand, a decrease in current would result in a decrease in voltage, which would result in a lower resistance in the circuit.

5. How does current flow affect the overall performance of an electric circuit?

The flow of current is essential for the proper functioning of an electric circuit. Without a current, there would be no flow of electrons, and therefore no transfer of energy. Additionally, the amount of current in a circuit can affect the efficiency and power of the circuit, as well as the brightness of the lights or strength of the devices connected to it.

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