If an electron is repelled by another electron how do we get current?

[SHASHWAT PRATAP SING]

As we know that An electric current is a flow of electric charge in a circuit and In electric circuits the charge carriers are often electrons moving through a wire.
Now, since we know that Like charges repel each other then how do the electrons flow through a wire since they are like charges they should repel each other.
Please help me

 

[Dale]

Don't forget the protons. They are still present even if they are not moving.

 

[SHASHWAT PRATAP SING]

Don't forget the protons. They are still present even if they are not moving.

Yes.

 

[PeroK]

In the simplest model of a current it is the repulsive force from one electron set in motion that sets the next electron in motion etc.

 

[kuruman]

If an electron gets pushed harder from, say the electron on its left than the electron on its right, it will move to the right. If you imagine now a chain of electrons each of which experiences a net force to the right, they will all move to the right. Of course, for that to happen you need a force field that is external to the electrons and pushes them all in the same general direction. This is the electric field created by establishing an electric potential difference (or voltage) across the ends of a conductor.

 

[SHASHWAT PRATAP SING]

If an electron gets pushed harder from, say the electron on its left than the electron on its right, it will move to the right. If you imagine now a chain of electrons each of which experiences a net force to the right, they will all move to the right. Of course, for that to happen you need a force field that is external to the electrons and pushes them all in the same general direction. This is the electric field created by establishing an electric potential difference (or voltage) across the ends of a conductor.

you explain very well.
kuruman I want to know that At the negative terminal where the one end of the conductor is connected the electrons in the conductor on the side of the negative terminal feel repulsion due to negative charges on the negative terminal now the very first electron feels repulsion we can say it is a valence electron so now this valence electron jumps to its neighbour atom.
kuruman here I want to know that Now what does this valence electron do Does this valence electron repels another valence electron of this neighbour atom or the valence electrons of this neighbour atom repel this valence electron to move it further, I want to know the process now what happens hereafter ?

 

[anorlunda]

, I want to know the process now what happens hereafter

Try reading about the Drude model. It is not the whole story but it is a good start.

https://en.m.wikipedia.org/wiki/Drude_model

 

[artis]

@SHASHWAT PRATAP SING , well you are correct electrons do repel each other but in a metal which is the most used type of conductor the electrons are not entirely free as they would be in a electron cloud or beam in vacuum. Metals that are good conductors simply have their atomic structure in such a way that each atom has many electrons, each of those is located within a different shell/energy level (distance away from the nucleus) , it just so happens to be that for good conductors these last outermost electrons are "almost free" which means they are bound to the nucleus very loosely, the strength with which electrons are bound to a nucleus is measured in eV or electron-volts.In fact for electrons moving in a beam in vacuum the only reason they don't just fly apart is because of the potential difference that accelerates them and even then there is a limit to how close each electron is to each next one, because they all repel one another.

 

[SHASHWAT PRATAP SING]

@SHASHWAT PRATAP SING , well you are correct electrons do repel each other but in a metal which is the most used type of conductor the electrons are not entirely free as they would be in a electron cloud or beam in vacuum. Metals that are good conductors simply have their atomic structure in such a way that each atom has many electrons, each of those is located within a different shell/energy level (distance away from the nucleus) , it just so happens to be that for good conductors these last outermost electrons are "almost free" which means they are bound to the nucleus very loosely, the strength with which electrons are bound to a nucleus is measured in eV or electron-volts.In fact for electrons moving in a beam in vacuum the only reason they don't just fly apart is because of the potential difference that accelerates them and even then there is a limit to how close each electron is to each next one, because they all repel one another.

I want to know what happens hereafter-

@kuruman I want to know that At the negative terminal where the one end of the conductor is connected the electrons in the conductor on the side of the negative terminal feel repulsion due to negative charges on the negative terminal now the very first electron feels repulsion we can say it is a valence electron so now this valence electron jumps to its neighbour atom.
@kuruman here I want to know that Now what does this valence electron do Does this or , I want to know the process now what happens hereafter ?

Does this valence electron repels another valence electron of this neighbour atom to move it out out this neighbour atom or the valence electrons of this neighbour atom repel this valence electron to move it further.

 

[Dale]

Does this valence electron repels another valence electron of this neighbour atom to move it out out this neighbour atom or the valence electrons of this neighbour atom repel this valence electron to move it further.

I think that this is a poor way to think of it.

You have an electric field produced by the charges on the battery terminals and the surface charges along the wire. The free charge simply moves as dictated by that electric field. They do not interact with each other much because they are largely shielded from each other by the fixed charge. It is only the surface charges that really do much because those are not shielded.

That is why I said in my first post to not forget the protons, which you appear to have done in every subsequent post.

[personal opinion] Generally, if you are not in a class on chemistry or on quantum mechanics, you should not be discussing electrons. Typically if you are discussing electrons outside of those two contexts then you are going to be making a mistake and essentially just making something that is simple much more complicated than it needs to be without introducing any benefit or getting any way closer to the way things actually work. [/personal opinion]

 

[sophiecentaur]

Does this valence electron repels another valence electron of this neighbour atom to move it out out this neighbour atom or the valence electrons of this neighbour atom repel this valence electron to move it further.

I thought that the accepted model of metallic charge conduction (i.e. wires) is that there is a cloud of dissociated electrons which are held roughly in place by the lattice of positive ion cores but not by particular atoms. They are free to move with a field of very near zero. The work done in moving them over a Potential Difference is interpreted as Resistance in the formulaE W = qV / V=IR / P=VI etc.
The forces that keep metals together give the well known metallic mechanical properties and are described as 'metallic bonding'.

 

[vanhees71]

A qualitatively pretty good classical model is the Drude model (corrected by Sommerfeld to take into account the Fermi statistics and thus the correct relation between electric and heat conductivity, the Wiedemann-Franz Law, but that's a different topic).

According to this simplified model a metal consists of a positively charged crystal lattice within which the atomic nuclei and part of the electrons are bound. Roughly you can consider them just as a homogeneous positive-charge background ("jellium model"). In this positive-charged background the conduction electrons are able to move almost freely but due to the thermal motion of the crystal lattice as well as defects of this lattice there is some friction of this "conduction-electron fluid".

Now if you have some external electromagnetic field (e.g., connecting the poles of a battery with a wire) the equation of motion (here in non-relativistic approximation, which is as good as exact for usual household currents, because the velocity of the conduction electrons is of the order of a milli-meter per second) thus reads
$$m \ddot{\vec{x}}=-e (\vec{E}+\dot{\vec{x}} \times \vec{B})-m \gamma \dot{\vec{x}},$$
where $m \gamma$ is some friction coefficient.

Now let's consider a DC (time-independent) case. Usually a pretty short time after switching on the DC, then the electromagnetic force is just compensated by the friction force and thus $\dot{\vec{x}}=\text{const}$. Then you have
$$m \gamma \dot{\vec{x}}=-e(\vec{E}+\dot{\vec{x}} \times \vec{B}) \simeq -e \vec{E}.$$
In this extremely non-relativistic case you can neglect the magnetic part of the Lorentz force (not so if you consider the full relativistic description, but that's a gain another story!).

Now let $n$ be the number density of conduction electrons. Then mutliplying the above equation by $-e n/(m \gamma)$, you get
$$-n e \dot{\vec{x}}=\vec{j}=\frac{n e^2}{m \gamma} \vec{E}=\sigma \vec{E},$$
where $\sigma$ is the electric conductivity.

 

[artis]

@SHASHWAT PRATAP SING

I want to know what happens hereafter-

Well nothing really happens , it was just an explanation.@sophiecentaur @vanhees71 Well the way I understand metal conduction is that the metal atoms form the so called lattice structure (different for different types of metals) and the outermost electrons of each atom are bound extremely loosely so that even a tiny potential can set them free and cause current.
But I guess that both the fact that the outer electrons are bound very weakly as well as the lattice structure are needed for good conduction , would that be a fair argument ?

Although from the following link I find an explanation that is almost identical to @sophiecentaur posted one
https://chem.libretexts.org/Bookshe...Properties/6.04:_Crystal_Structures_of_Metals

the valence electrons become "smeared out" or delocalized over all the atoms in the crystal. It is best to think of the bonding in metals as a crystalline arrangement of positively charged cores with a "sea" of shared valence electrons gluing the structure together. Because the electrons are not localized in any particular bond between atoms, they can move in an electric field, which is why metals conduct electricity well.

@SHASHWAT PRATAP SING be sure to check out the links from this post, also this one.
https://depts.washington.edu/matseed/mse_resources/Webpage/Metals/metalstructure.htm

 

[vanhees71]

It's of course clear that for a real understanding of everything related to "matter" in terms of its microscopic constituents you need quantum theory, and indeed the conduction electrons in a metal are delocalized. The simple classical Drude model I described above is only a crude heuristic model!

 

[Herman Trivilino]

Now, since we know that Like charges repel each other then how do the electrons flow through a wire since they are like charges they should repel each other.

A conduction electron has forces exerted on it. Certainly it responds to the force exerted on it by other electrons, but it also responds to the force exerted on it by a battery.

 

[artis]

@SHASHWAT PRATAP SING Also note that we can achieve much higher currents in metallic conductors than in vacuum if we take similar cross section for a wire and for a electron beam.
The reason is the space charge effect that dominates electron currents in vacuum because they strongly repel one another while in solid conductors due to the atomic structure the electrons can be much closer to one another, and also there are many more electrons per given area.

 

[Vanadium 50]

I find the whole question puzzling.

Take a wire. It has electrons, which repel (and positive charges in it as well). Put extra electrons on one side. Let them repel. At the opposite side what do you think you will see?

1. Negative charge? (i.e. a current)
2. No charge? (i.e. the electrons remained at the other end?)
3. Positive charge?

 

[cmb]

The nature of 'a repulsive force' in such a question is itself potentially something that can misdirect the unwary.

Forces are emergent representations of the rate of change of energy of a system with respect to a displacement within it. If electrons (or any charge come to that) can move and by doing so decrease the energy of a system by rebalancing a charge imbalance, then they will experience a 'motive force' to do so.

Or if you want that in more common language, they will be motivated to reduce the system energy, and so if there is a 'charge' somewhere in the system which has increased the system energy, the electrons will move, if they can, into a position to minimise that energy.

We get very attached to the idea of forces because that is what we 'experience'. But in fact a motive force derives from F = dE/dx, but we don't 'experience' rates of change of energy wt displacement so we don't notice that sort of thing.

Therefore, in regards what electrons experience 'between' them doesn't matter. It becomes a bulk property of a lot of electrons all moving to minimise the system energy and reduce any charge imbalances.

 

[sophiecentaur]

Also note that we can achieve much higher currents in metallic conductors than in vacuum if we take similar cross section for a wire and for a electron beam.

. . . . and the Energy in an electron beam (in a vacuum) tends to be carried I the form of Kinetic Energy. The electrons have such high velocities, compared with drift velocity in a solid, that the v² factor rapidly becomes significant. The KE thing in metals is a popular misconception but can apply in a vacuum.