Electric Potential, and Potential Difference

In summary: I CONCEPTUALLY CORRECT HERE?Yes, if you go from point A ---> point B, and you've got a potential of 100V at point A and 0V at point B, then the potential difference is B - A = 0V - 100V = -100V.
  • #1
Baumer8993
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In my physics class we are learning about electric potential right now. I know electric potential is electric potential energy with the charge divided out. I am curious if the potential difference is just the difference between the two points.

My thinking is we have point A, and B. The path goes from A to B. Point A has an electric potential of 100 volts, and point B has an electric potential of 0 volts. If I am correct in my thinking the potential difference between the two is -100 volts.

Am I conceptually right here? I find it hard to keep straight electric potential, potential difference, and electric potential energy.
 
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  • #2
Yeah if you go from point A ---> point B, and you've got a potential of 100V at point A and 0V at point B, then the potential difference is B - A = 0V - 100V = -100V.

Electric potential is a value that tells you about a point in space. You can think of it as a "property" that is describing the electric field at a point. At point A the electric potential is 100V, it doesn't matter what kind of charge you put at that point, the electric potential at point A is always 100V.

Electric potential energy is a value that you use to describe the charged objects in electric fields. At point A, the electric potential energy of a charged object would be some number of eV (electron volts, a unit of energy). It depends on the electric potential, and thus the electric field, but it is a property of a given charged object in a field.

Electric potential describes points in a field. Electric potential energy describes objects in a field.
 
  • #3
Baumer8993 said:
In my physics class we are learning about electric potential right now. I know electric potential is electric potential energy with the charge divided out. I am curious if the potential difference is just the difference between the two points.

My thinking is we have point A, and B. The path goes from A to B. Point A has an electric potential of 100 volts, and point B has an electric potential of 0 volts. If I am correct in my thinking the potential difference between the two is -100 volts.

Am I conceptually right here? I find it hard to keep straight electric potential, potential difference, and electric potential energy.
The potential difference of point a relative to point b, is determined by the force that the electric field exerts on a unit positive charge multiplied by the distance from a to b x the cosine of the angle between the direction of force and the distance. If you know calculus:

[tex]V = \int_a^b \vec{E}\cdot d\vec{s}[/tex].

The potential energy of a charge at a given point in an electric field has no meaning by itself. It only has meaning in reference to another point. So the only thing that matters is the potential difference. You can arbitrarily set one point at 0 if you like.

In order to determine the sign of the potential difference you have to use the force on a positive charge. So, for example, if the field pushes a positive charge from a to b the potential difference from a to b is positive. If you have to push the positive charge from a to b, the potential difference will be negative.

AM
 
Last edited:

1. What is Electric Potential?

Electric potential, denoted as V, is a measure of the electric potential energy per unit charge at a given point in space. It is defined as the work done per unit charge in moving a test charge from infinity to a specific point in an electric field.

2. What is Potential Difference?

Potential difference, also known as voltage, is the difference in electric potential between two points in an electric field. It is a measure of the energy that is required to move a unit of electric charge from one point to another.

3. How is Electric Potential related to Potential Difference?

Electric potential and potential difference are closely related. Electric potential is a scalar quantity, while potential difference is a vector quantity. The potential difference between two points is equal to the change in electric potential between those two points.

4. What is the unit of measurement for Electric Potential and Potential Difference?

The unit for both electric potential and potential difference is the volt (V). One volt is equivalent to one joule per coulomb (J/C).

5. How is Electric Potential and Potential Difference calculated?

Electric potential is calculated by dividing the work done in moving a test charge by the magnitude of the charge. Potential difference is calculated by subtracting the initial electric potential from the final electric potential.

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