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

In summary, the conversation revolves around the creation of an EMF on a conductor by applying an external electrical field. The possibility of creating a 2∑ voltage instead of just ∑ is discussed, considering the concept of hole current in semiconductors. The difference between conductors and semiconductors in terms of charge carriers and their effect on resistance is also mentioned. It is noted that semiconductors do not necessarily follow Ohm's law and the presence of minority charge carriers can affect the current and resistance.
  • #1
Ozgen Eren
51
1
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
 
Last edited:
Physics news on Phys.org
  • #2
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.
 
Last edited:
  • #3
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.
 
  • #4
Dont confuse the model with reality.
 

What is a current?

A current is a flow of electric charge through a conducting material, typically measured in amperes (A). It is caused by the movement of electrons or ions and is essential for powering electrical devices.

What is an electrical field?

An electrical field is a region in space where electrically charged particles, such as electrons or ions, experience a force. This force is caused by the presence of an electric charge and can be represented by electric field lines.

How is current related to electrical fields?

Current is directly related to electrical fields. The movement of charged particles, which constitutes a current, is influenced by the strength and direction of the electric field. Higher electric fields result in a greater force on the particles and thus a higher current.

What factors affect the strength of an electrical field?

The strength of an electrical field is affected by the distance between the charged particles, the magnitude of the charges, and the medium through which the charges are moving. The electric field is stronger when the distance between charges is smaller, the charges are larger, and the medium has a lower resistance.

What are some practical applications of electrical fields?

Electrical fields have a wide range of practical applications, including powering electronic devices, transmitting electricity through power lines, and generating energy through generators. They are also used in medical procedures such as electrocardiograms and electroencephalograms, and in technologies such as capacitive touch screens and electric motors.

Similar threads

  • Electromagnetism
Replies
14
Views
1K
Replies
3
Views
486
Replies
14
Views
1K
  • Electromagnetism
Replies
15
Views
1K
  • Electromagnetism
Replies
7
Views
955
Replies
9
Views
1K
  • Electromagnetism
Replies
4
Views
970
Replies
2
Views
678
  • Electromagnetism
2
Replies
36
Views
3K
Back
Top