Conducting Rod in Electric Field

Click For Summary

Discussion Overview

The discussion revolves around the behavior of an uncharged metal rod placed in a uniform electric field, specifically whether a potential difference develops between its ends and how this potential difference relates to the external electric field.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • One participant questions if a potential difference develops across the ends of the rod when placed in an electric field E.
  • Another participant suggests that the potential difference can be calculated using the integral of the electric field over the distance between the ends of the rod.
  • Some participants argue that any potential difference would be short-lived due to the rearrangement of charges within the conductor, leading to no potential drop across it.
  • However, one participant challenges this view, proposing that a potential difference will develop and persist within the conductor, resulting in an internal electric field that opposes the external field.
  • Another participant agrees that the electric field inside the conductor will be zero, implying that the potential difference calculated over the length of the conductor would also be zero.

Areas of Agreement / Disagreement

Participants express differing views on whether a potential difference develops and persists within the conductor, leading to unresolved disagreement on this topic.

Contextual Notes

The discussion highlights the dependence on the definitions of potential difference and electric fields, as well as the assumptions regarding charge distribution in conductors under external electric fields.

Apteronotus
Messages
201
Reaction score
0
If an uncharged conductor, a metal rod say, is placed in a uniform electric field E, parallel to the field (see figure), does it develop a potential difference between its two ends?

If so, how is the potential difference related to the field E?
 

Attachments

  • Conductor_in_EField.JPG
    Conductor_in_EField.JPG
    4.5 KB · Views: 694
Physics news on Phys.org
Apteronotus said:
If so, how is the potential difference related to the field E?

By the definition, the electric potential, as the energy required to bring a point charge from point B to point A, is given by the negative integral of E over the distance dr from B to A. That is,
\int^{B}_{A}Edr
Just try to apply this on your case where A and B are different positions of the ends.
 
Well, if there is a potential difference, it will be very short lived. Since this is a conductor, the charge inside the conductor will re-arrange itself so that there is no potential drop across the conductor.
 
kcdodd said:
Well, if there is a potential difference, it will be very short lived. Since this is a conductor, the charge inside the conductor will re-arrange itself so that there is no potential drop across the conductor.

Yes I think you're right! And remember the concept of bound and free charges.
 
kcdodd said:
Well, if there is a potential difference, it will be very short lived. Since this is a conductor, the charge inside the conductor will re-arrange itself so that there is no potential drop across the conductor.

Actually, I'm not sure this is true. I've given the problem some thought since my original posting. I think a potential difference will in fact develop (and maintain) within the conductor. It's effect will be an electric field within such that the magnitude of the field will be equal to that of the imposed electric field (outside field) and will point in the opposite direction.

So the superposition of the two fields will be zero within the conductor.
 
Yes, the field will be zero within the conductor. So, if you do a line integral from one end to the other you will get zero for the potential difference.
 

Similar threads

High School Thought Experiment on Charge Carriers and Electrical Conduction
  • · Replies 3 ·
Replies
3
Views
909
High School Electric Fields inside Conductors & Gauss' Law
  • · Replies 7 ·
Replies
7
Views
1K
High School Curious about the uniform electric field between metal plates
  • · Replies 8 ·
Replies
8
Views
2K
Undergrad Electric Field Shielding by Conducting Sheets
  • · Replies 3 ·
Replies
3
Views
2K
High School Magnetic field produced by an electric current
  • · Replies 5 ·
Replies
5
Views
2K
Undergrad Magnetic field when the area of the plates of a capacitor increases
  • · Replies 7 ·
Replies
7
Views
2K
Undergrad How is Potential Difference Created across a Resistor?
  • · Replies 21 ·
Replies
21
Views
4K
Undergrad Electric field, flux, and conductor questions
  • · Replies 14 ·
Replies
14
Views
3K
Undergrad Electric Field of Uniformly Charged Infinite Plane
  • · Replies 6 ·
Replies
6
Views
483
Undergrad Do valence electrons determine electrical conductivity?
  • · Replies 1 ·
Replies
1
Views
3K