Understanding Electric Fields and Potential in Parallel Plate Conductors

In summary, an electric field is due to two parallel plate conductors carrying equal and opposite charges. The higher potential plate is the positive plate.
  • #1
KLscilevothma
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If an electric field is due to 2 parallel plate conductors carrying equal and opposite charges, which plate got the higher potential, positive one or negative one?

Electric potential = Q/(4*pi*ε*r)

If charge, Q is negative, electric potential is negative, does it mean that the negative plate has a lower potential than the positive one?

However in a battery, say a dry cell, negative terminal has higher potential then the positive one. Hm... I'm a little bit confused.
 
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  • #2
The positive plate is the plate of higher potential. If you let an electron in the middle of the two plates it will be accelerated to the positive plate
In a battery, the positive pole has the higher potential. In a circuit, the electrons go out of the negative pole, travel the circuit, and return to the positive pole. Is current in the drawings to represent that the electrons flow from positive pole to negative pole, but this sense for the current, named "conventional current", it's not the real. It's made this way for historical reasons, but i think that conventional current should be eliminated
 
  • #3
In some sense I agree that 'conventional current' is a rather bad historical hold-out, except that really, it's just a convention. It's no worse that the right-hand rule, or any of the other conventions in physics.

The physics of most of the electronics world doesn't change if you use positive charges moving in one direction, or negative charges moving in the other direction. For example, a wire carrying positive charges in one direction and a wire carrying negative charges in the other direction will produce identical magnetic fields. Since both of these currents result in the same phenomena, it makes sense to refer to them both as being the "same" current. The direction chosen to represent that current happens to correspond to the direction positive charges would move. Sure, the charge carriers in most electronics are actually negative -- but in semiconductors, the charge carriers can just as easily be positive.

- Warren
 
  • #4
Thanks for your replies.

so does it mean electrons move from lower potential region to higher potential region in an E field while a positive charge moves from higher potential area to lower potential area ? And field lines are drawn from higher potential region to lower potential region, right?

If a postive charge is placed in an E-field, it moves from higher potential region to lower potential region, loss in pe becomes gain in ke, that makes sense to me.

Ok, if an electron is placed in an E-field, it gains electronic potential energy by moving from lower potential region to higher potential region. At the same time, it accelerates to the higher potential region and thus gain in ke also. Where does the gain in energy come from?

in semiconductors, the charge carriers can just as easily be positive
I've heard of it too. I'm imagining large positive charge carriers move to one side while small electrons just stay still. Kinda interesting though perhaps that's a false imagination. :smile:
 
  • #5
What charges (possitive or negative) want to do is rise to zero potential difference in the system, or equalization.

Imagine an sphere with electrons. It is at a lower potential (-V) due to their charge and inner repulsion. The electrons will go to infinity, to a higher potential (0V), but from the point of view of the electrons, it is in fact a "lower" potential.

The charges increment or decrement their inner PE, but in order to equalyze or reduce the total potential difference in the system.

When an an electron moves from lower PE to higher PE, it's just annuling some PE difference that existed.

But your question is still interesting, and i hope someone could explain it in a better way.
 
  • #6
cala,

Why do you post in this thread? You have no idea what you're talking about.

- Warren
 

1. What is an electric field?

An electric field is a physical phenomenon that describes the force exerted by an electrically charged particle on another charged particle. It is a vector quantity, meaning it has both magnitude and direction.

2. How is an electric field created?

An electric field is created when a charged particle, such as an electron or proton, is present. The charged particle creates an electric field around itself, which can influence the movement and behavior of other charged particles in the field.

3. What is the difference between an electric field and an electric current?

An electric field is a force field that exists around a charged particle, while an electric current is the movement of electrically charged particles through a conducting material. Electric fields can influence the movement of electric currents, but they are not the same thing.

4. How is the strength of an electric field measured?

The strength of an electric field is measured in units of volts per meter (V/m). This unit represents the amount of force (in volts) exerted on a charged particle in the field over a distance of one meter.

5. What are some real-life applications of the concept of electric fields?

Electric fields have many practical applications, including powering electronic devices, generating electricity in power plants, and controlling the movement of charged particles in medical equipment such as MRI machines. They are also used in technologies such as telecommunication and radar systems.

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