How does electric current change electric potential?

In summary, the injection of X amps of current into an electrically insulated box will change the electric potential by an amount equal to the capacitance of the box multiplied by the charge placed on it. The higher the capacitance of the box, the more charge is needed to increase the potential, meaning that a higher current is required to produce the same change in potential. This can be compared to filling a container with water, where a larger container requires a larger water current to reach the same level in the same amount of time.
  • #1
Apteronotus
202
0
Suppose we have an electrically insulated box in a room, and the potential difference between the box and the room is given by [tex]V_1=V_{Box1}-V_{room}[/tex].

Now suppose we inject the box with X amps of current, for t seconds. The new voltage is now given by [tex]V_2=V_{Box2}-V_{room}[/tex]

By how much does the injection of X amps of current change the electric potential of the box?
ie.
What is [tex]V_{Box1}-V_{Box2}[/tex]?
 
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  • #2
It depends on the capacitance of the box. V=Q/C
and Q = It
Your current has placed more charge on the box so its potential will rise according to the value of its capacitance.
Edit
Use V=Q/C and write an expression for V1 and V2 in terms of the charge on the box and its capacitance.
 
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  • #3
So can we equate the two equations you've written and simply say [tex]CV=It[/tex]?

Also,
if the box is a good electrical insulator, then we expect it to have a high capacitance (ability to hold an electrical charge), right?
But then by the CV=It above, the higher the C is the less effect a current I will have on the potential V. What's the intuitive meaning behind this?
 
  • #4
Apteronotus said:
So can we equate the two equations you've written and simply say [tex]CV=It[/tex]?
The initial pd on the box is given by V1=Q/C where Q is the initial charge and C its capacitance.
The final pd of the box (V2) is found by putting the charge on it equal to Q + It (and the same value of C.)
You then find V2 - V1
Also,
if the box is a good electrical insulator, then we expect it to have a high capacitance (ability to hold an electrical charge), right?
But then by the CV=It above, the higher the C is the less effect a current I will have on the potential V. What's the intuitive meaning behind this?

The definition of C is that it equals Q/V
The intuitive part of this is that the higher the value of C, the more charge you need to increase the pd. So as current is flow of charge, the higher the capacitance means that you need more current to increase the pd.
I always think of water in a container. The pd is the depth of the water, and the capacitance is the capacity (volume) of the container. The bigger the capacity of the container, the more water you need to raise its level.
If you were filling it with a hose pipe, you would need a larger water current to fill a larger container to the same depth in the same time.
 
  • #5


Electric current is the flow of electric charge through a conductor. When a current flows through a material, it creates an electric potential difference, or voltage, between different points in the material. This voltage is a measure of the energy required to move a unit of charge from one point to another.

In the scenario described, the electric potential difference between the box and the room is initially V_1. When X amps of current is injected into the box for t seconds, the new voltage becomes V_2. This change in voltage is due to the movement of electric charge within the box.

The exact amount by which the injection of X amps of current changes the electric potential of the box can be calculated using Ohm's law, which states that the voltage (V) is equal to the current (I) multiplied by the resistance (R) of the material: V = I * R. In this case, the resistance of the box remains constant, so we can rearrange the equation to solve for the change in voltage (ΔV): ΔV = I * R * t.

Therefore, the injection of X amps of current for t seconds will result in a change in voltage of ΔV = X * R * t. This means that the electric potential difference between the box and the room will change by this amount, or V_{Box1}-V_{Box2} = X * R * t.

In summary, the injection of electric current into the box will change the electric potential of the box by an amount determined by the current, resistance of the material, and the time for which the current flows.
 

1. How is electric current related to electric potential?

Electric current is the flow of electric charge, usually carried by electrons, through a conductor. Electric potential, on the other hand, is the amount of work needed to move a unit of charge from one point to another. These two concepts are related through Ohm's law, which states that electric current is directly proportional to electric potential and inversely proportional to resistance.

2. How does electric current affect electric potential?

When electric current flows through a conductor, it encounters resistance, which causes a drop in electric potential. This is known as voltage drop. The amount of voltage drop depends on the resistance of the conductor and the amount of current flowing through it. As current increases, the voltage drop also increases, resulting in a decrease in electric potential.

3. What is the difference between electric current and electric potential?

Electric current is the flow of electric charge, while electric potential is the amount of work needed to move a unit of charge from one point to another. In other words, electric current is the movement of charge, while electric potential is the energy stored in the charges. Electric potential is also known as voltage.

4. How does resistance affect electric potential and current?

Resistance is the measure of how difficult it is for electric current to flow through a conductor. As resistance increases, the voltage drop also increases, resulting in a decrease in electric potential. This can also lead to a decrease in electric current, as it becomes more difficult for charges to flow through the conductor.

5. How can we change the electric potential of a circuit?

The electric potential of a circuit can be changed by altering the voltage source or by changing the resistance in the circuit. Increasing the voltage source will increase the electric potential, while increasing the resistance will decrease the electric potential. Additionally, connecting multiple sources of different voltages in series or parallel can also change the overall electric potential of the circuit.

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