Electric Potential Difference diagram

In summary, the question involves point charges q and Q positioned at a distance of 3.0m and 4.0m respectively. The task is to find the electric potential difference between points A and B, where q = +1.0 nC and Q = -2.0 nC. Using the equation V = ke (q/r), the potential at point A from the upper charge is found to be 2.9967 V and the potential at B from both charges is found to be -4.495 V. The potential difference between the two points can be calculated by subtracting these values, resulting in a final answer of 7.491 V.
  • #1
sugz
110
0

Homework Statement


Point charges q and Q are positioned as shown. If q= +1.0 nC, Q = -2.0 nC, a = 3.0m, and b = 4.0m, what is the electric potential difference, Va - Vb? **The question with the diagram is also attached **

Homework Equations


V = ke (q/r)

The Attempt at a Solution


V = (8.99x10^9)[(1.0x10^-9)/4) = 2.2475 V.

The anser is 3.6V though, so I don't understand what I am doing wrong!
 

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  • #2
You are computing the electric potential at the -2 nC charge resulting from the other. This is not what is being asked for.

How would you compute the potentials at the points A and B?
 
  • #3
How would you suggest to go about it? Because I tried it with the -2.0nC as well and i still didn't get the right answer :/
 
  • #4
What you are trying is not what is being asked for.

How would you compute the potential at the point A resulting from the upper charge?
 
  • #5
what do you mean by the upper charge?
 
  • #6
The upper charge in your image is the 1 nC charge.
 
  • #7
The potential at that point would be V=ke(q/r), where q is the 1 nC charge and r is a?
 
  • #8
Yes. So what would be the potential at that same point from the other charge?

In the same fashion, what would be the potential at B from both charges?
 
  • #9
So the potential at A is V= (8.99e9)(1e-9)/3 = 2.9967 V. The potential at B is V= (8.99e9)(-2e-9)/4 = -4.495 V?
 
  • #10
No, you need to compute the potential at both points using both charges and the correct distances.
 
  • #11
I'm sorry but I am quite confused right now and I really don't understand how to go about this question! Do you mind explaining conceptually why i have to find the potential at each point for both charges?
 
  • #12
Because both charges contribute to the potential at both points and you are interested in the potential difference between the points. The situation is not that of a single point charge.
 
  • #13
Oh that's what I was forgetting, thank you! It makes so much more sense now! :)
 

Related to Electric Potential Difference diagram

What is an Electric Potential Difference diagram?

An Electric Potential Difference diagram, also known as an Electric Field diagram or Electric Potential Energy diagram, is a visual representation of the electric field and potential energy at different points in space surrounding a charged object or system. It helps to visualize the direction and strength of the electric field and how it affects the potential energy of charged particles.

How is an Electric Potential Difference diagram created?

An Electric Potential Difference diagram is created by first determining the electric field strength at different points in space using mathematical equations, such as Coulomb's Law. The electric field lines are then drawn to show the direction of the field. Next, the potential energy is calculated at each point and represented by the height of the diagram. The higher the potential energy, the higher the height of the diagram.

What information can be obtained from an Electric Potential Difference diagram?

An Electric Potential Difference diagram can provide information about the direction and strength of the electric field, the potential energy at different points in space, and the relationship between the two. It can also show how the electric field and potential energy change as distance from the charged object or system varies.

How is the electric potential difference related to the electric field and potential energy?

The electric potential difference, also known as voltage, is directly related to the electric field and potential energy. It is a measure of the work needed to move a unit of charge from one point to another in an electric field. As the electric field increases, the potential energy and potential difference also increase. Similarly, as the distance from the charged object or system increases, the potential energy and potential difference decrease.

Why is an Electric Potential Difference diagram important in understanding electricity?

An Electric Potential Difference diagram is important in understanding electricity because it helps to visualize and understand the complex relationships between electric fields, potential energy, and potential difference. It also provides a way to predict how charged particles will behave in different situations, which is crucial in many areas of science and technology, such as electronics and electrochemistry.

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