Does Applying an Electrical Field to One Side of a Conductor Double the EMF?

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Discussion Overview

The discussion revolves around the effects of applying an electrical field to one side of a conductor and its implications for electromotive force (EMF). Participants explore the relationship between electric fields, current, and voltage, particularly in the context of conductors versus semiconductors.

Discussion Character

  • Debate/contested
  • Technical explanation
  • Conceptual clarification

Main Points Raised

  • One participant proposes that applying an electrical field to one side of a conductor might create an EMF of 2∑ due to the movement of electrons and the concept of hole current in semiconductors.
  • Another participant clarifies that V=IR is Ohm's law and emphasizes that the electric field and electric potential are distinct concepts.
  • A different participant points out that the initial claim refers to conductors, not semiconductors, and notes that semiconductors have two types of charge carriers, while conductors primarily involve electron movement.
  • One participant cautions against confusing theoretical models with real-world behavior, suggesting a need for careful consideration of the underlying physics.

Areas of Agreement / Disagreement

Participants express differing views on the nature of charge carriers in conductors versus semiconductors, and there is no consensus on whether the EMF created would be ∑ or 2∑. The discussion remains unresolved regarding the implications of applying an electrical field to the conductor.

Contextual Notes

Participants highlight the differences in behavior between conductors and semiconductors, noting that the treatment of charge carriers varies significantly between the two materials. There is also an acknowledgment of the limitations of applying Ohm's law to semiconductors.

Ozgen Eren
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Assume a conductor in a rectangle shape for simplicity.

Now, if I only choose one side of this rectangle, and apply external electrical field ∑ only to it, what EMF would I create on the conductor? I would simply say ∑, however then I had the following idea, and I started to doubt if I create 2∑ instead.

Here is what bugs me:
(say ∑=I*R, kirchhoffs law: R is the conductors resistance, ∑ is the field we apply)
Since nucleus of atoms are almost stable, most current will be due to electron movement, accelerating due to the force of the electrical field. Then electrons will create a current I obviously.

However, there is this topic we covered in semiconductors class in university, that is called hole current. Since electrons move from one atom to other atom, the destination atom is should initially be positively charged to be able to get the atom. When electron completes its movement, destination atom is now neutral, but the source atom is positively charged.

Although only one electron moved physically, there is also a positively charged 'hole' moved in the opposite direction, which doubles the equivalent current, making it 2I. Then it means we had created 2∑ equivalent voltage on the semiconductor by applying only ∑ electrical field.

Do we have ∑ or 2∑ voltage as a result of this experiment?

Here is the wiki page for electron hole:
https://en.wikipedia.org/wiki/Electron_hole

In here, its stated that we treat differently to metals and semiconductors, (we ignore holes in metals) which do not answer the question but adds another dimension to it:
https://en.wikipedia.org/wiki/Charge_carrier
 
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V=IR ... here, V would be the potential difference along the conductor. This is Ohm's law, not Kirchoffs.
The electric field with the electric potential are different things.
If the same voltage gets a higher current, it means the resistance is lower.

You state at the start that the test material is a conductor... not a semiconductor.
Semiconductors don't have to obey Ohm's law.
Semicondictors are usually modeled with only one type of charge carrier ... also remember that a "hole" is the absence of an electron.

Note: where there is a minority charge carrier, you do need to account for it when figuring the current... so you'd get more current for the same voltage... which means the resistance is lower than it would be if only one carrier were present.
 
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Simon Bridge said:
Semicondictors are usually modeled with only one type of charge carrier ... also remember that a "hole" is the absence of an electron..

I think you meant conductors here...not semiconductors. Semiconductors generally have two types of charge carriers, electrons and holes. Conductors generally have only electrons contributing to conduction.
 
Dont confuse the model with reality.
 

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