Potential difference between two points

Click For Summary

Discussion Overview

The discussion revolves around the conditions necessary for current to flow between two points, A and B, particularly focusing on the role of potential difference. Participants explore the relationship between potential difference, resistance, and current flow in electrical circuits.

Discussion Character

  • Debate/contested
  • Technical explanation

Main Points Raised

  • One participant asserts that current flow requires a potential difference between two points, questioning why current flows between points A and B if they are at the same potential.
  • Another participant challenges this assertion, suggesting that current can flow even without a potential difference, using the analogy of water flow to illustrate the concept.
  • A later reply indicates that while a potential difference is typically required for current flow, a very small potential drop can exist due to wire resistance, allowing current to flow between A and B.
  • Another participant explains that the potential difference exists between the battery's terminals and that current flows through points A and B due to conservation of charge, regardless of local potential differences.
  • One participant elaborates that current can flow without a potential difference if resistance is zero, emphasizing that the overall current is influenced by the energy conversion in the battery and the distribution of resistances in the circuit.

Areas of Agreement / Disagreement

Participants express differing views on the necessity of potential difference for current flow, with some arguing that it is essential while others propose that current can flow under certain conditions without it. The discussion remains unresolved with multiple competing perspectives.

Contextual Notes

Participants reference Kirchhoff's rules and the concept of resistance, indicating that assumptions about ideal conditions (such as zero resistance) may affect the discussion. The relationship between potential difference, resistance, and current magnitude is also highlighted but remains complex and not fully agreed upon.

nikhilthunder
Messages
2
Reaction score
0
we know the current flow only when there is a potential difference between two points.consider the point A and B in the file attached ,both A and B are at same potential then why the current flow between them
 

Attachments

  • ug.JPG
    ug.JPG
    2.6 KB · Views: 581
Last edited:
Physics news on Phys.org


Your first statement is wrong- you do NOT have to have a potential difference between two points in order to have electricity flow between them. Think of electricity as water flowing. "Potential difference" corresponds to different heights. Of course, water flows from higher to lower but you certainly can have water flowing along a flat area: the flow downhill before the flat section "pushes" the water ahead of it.
 
nikhilthunder said:
we know the current flow only when there is a potential difference between two points.consider the point A and B in the file attached ,both A and B are at same potential then why the current flow between them

Hi nikhilthunder! :smile:

(I flow, you flow, we flow, they flow, he flows, she flows, current flows :wink:)

hmm … good question …

any wire has a very very small resistance (which we usually ignore) …

so by Kirchhoff's rules there's a very small potential drop between A and B …

the current flows because of that potential difference. :smile:
 
Last edited:


A potential difference is required for current to flow. In this case, the potential difference exists between the positive and negative terminals of the battery. This potential difference creates a current flow once a complete path is established between the terminals. Points A and B have current flowing through them but very little voltage drop due to the wire resistance (and no voltage drop if an ideal wire is assumed). With or without a local potential difference between points A and B, current still flows through them since the source current entering point A must equal the current exiting point A (conservation of energy or KCL). The same goes for point B.

CS
 


tiny-tim said:
Hi nikhilthunder! :smile:

(I flow, you flow, we flow, they flow, he flows, she flows, current flows :wink:)

hmm … good question …

any wire has a very very small resistance (which we usually ignore) …

so by Kirchhoff's rules there's a very small potential drop between A and B …

the current flows because of that potential difference. :smile:


But the current would flow without said potential difference if the resistance were zero. It flows with or without said PD, but the resistance, plus the sum of all other resistances determines the magnitude of current, as long as the power source maintains a constant voltage.

The overall current flows because of the energy conversion taking place inside the battery. The distribution of various resistances around the loop determine the magnitude of the current, and the division of voltage.

Claude
 

Similar threads

Undergrad Understanding EMF and Potential Difference in Electrical Circuits
  • · Replies 6 ·
Replies
6
Views
3K
High School Difference Between Potential and Potential Energy
  • · Replies 55 ·
2
Replies
55
Views
5K
Undergrad Different Equations of Motion for different frames
  • · Replies 64 ·
3
Replies
64
Views
4K
Undergrad Air flow between sphere/cylinder and membrane
  • · Replies 1 ·
Replies
1
Views
1K
Undergrad What is the zero point for Potential Energy and how to find it from integral limits?
  • · Replies 6 ·
Replies
6
Views
2K
High School Conceptually understanding change in potential energy with 0 net work
  • · Replies 9 ·
Replies
9
Views
3K
Undergrad Why do phase trajectories point upwards and downwards in a quadratic potential?
  • · Replies 1 ·
Replies
1
Views
2K
Undergrad Measuring difference in Exercising in a Flat Surface vs one with Slope
  • · Replies 5 ·
Replies
5
Views
2K
High School What potential difference actually means
  • · Replies 4 ·
Replies
4
Views
1K
Graduate Salt water and potential difference
  • · Replies 8 ·
Replies
8
Views
3K