Questions tagged [electrons]

Negatively charged particle with spin 1/2. A component of mundane terrestrial matter, and part of all neutral atoms and molecules. It has a mass about 1/1800 that of a proton. Its antiparticle is the positron.

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1 answer
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Do electrons combine to form a single particle

I was reading about exchange interactions and stumbled across this website that was discussing symmetry and the exchange interaction. The website stated The exchange interaction is originated from ...
2 votes
0 answers
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How exactly does J. J. Thompson's cathode ray experiment show that electrons are particles?

I've have heard in many places that J. J. Thompson used a magnet and capacitor plates to look at the effects of the electric and magnetic fields on the cathode ray. This way, he was able to deduce the ...
1 vote
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Does laser trap atom cooling change the electron shell levels?

Do the electron orbits change during the cooling of the atom in a laser trap? When cooling down, do the electrons come closer to the nucleus of the atom or do they move away? Or do the electrons leave ...
-1 votes
1 answer
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Why is the specific charge for electron defined to be positive? [closed]

In some textbooks the specific charge of electron is defined as negative and in others it is positive. If specific charge =charge/mass . And an electron charge is negative shouldn't its specific ...
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Interference pattern of an electron passing through a semislit instead through a single slit

Is there a difference in the interference pattern of an electron between cases when it passes through a single slit and when it passes a "semislit", which I drew on the picture below to make ...
0 votes
2 answers
200 views

How are resistivity and tunneling related?

If we consider a sandwich with three nanometric layers: conductor-insulator-conductor and apply voltage (lower than breakdown voltage) from both sides tunneling will occur. Is tunneling dependent on ...
1 vote
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64 views

What kind of experiment could measure the total sphericity of the electron's monopole charge $E$-field? [duplicate]

As far as I know this was never experimentally undertaken with a high precision measurement, probably by measuring the $E$ interaction field around the monopole charge of an isolated electron (i.e. ...
10 votes
1 answer
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How do electrons and photons interact?

Two electrons, or an electron and a proton, interact with each other because of the Coulomb potential, which can also be seen in the Schrödinger equation (which is the equation that describes the ...
0 votes
2 answers
46 views

Particle like nature of electron in single-slit experiment

For explaining the double slit experiment, many such as Jim Al Khalili (https://www.youtube.com/watch?v=A9tKncAdlHQ) start with an example of having one slit - the pattern on the screen is that which ...
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Explaining Valence Electrons

I want to explain the concept of free electrons in a conductor vs. an insulator as simple as possible for children that have not yet learned about valence electrons. Would it make sense if I explained ...
0 votes
1 answer
200 views

Magnetic Dipole Moment of a single electron of a hydrogen atom CM vs QM

An electron in orbit is a good approximation of a magnetic dipole so n the introduction of chapter 8 in the book: "Quantum Physics of Atoms, Molecules, Solids, Nuclei and Particles", a classical ...
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9 answers
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If air is an insulator, how does an ungrounded electric generator move electrons?

Firstly, this is NOT a duplicate question. There have been similar questions asked, but no one has adequately explained this particular aspect of electric generators. Yes, they act as an electron "...
3 votes
2 answers
686 views

What is the magnetic field of a radially moving current?

Let's say free electrons are contained in a small cloud because of electrostatic forces confining them. Now, if those walls vanish, the cloud will expand very fast because of the coulomb force ...
4 votes
2 answers
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Doubt about the working principle of a silicon solar cell

I'm studying crystalline solar cell and their working principle, but I still don't completely understand the process. First of all, I understand that we dope a pure crystalline silicon with boron and ...
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1 answer
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What will happen if one electronic charge is given to a conductor?

I was taught in my physics class that if some charge is given to a conductor then the charge gets distributed over its entire surface. But what will happen if just an electron ( a point charge) was ...
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1 answer
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Connection between Laplace's equation and hydrogenic electron Schrodinger equation

Consider Laplace's equation: $\nabla ^2 V = 0$ This holds for an electric potential $V$ in a region of space where no charges are present. This includes a Coulomb potential of a hydrogen nucleus (...
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3 answers
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What does it mean when people (physicists) say electron has a wavelength of $x$ unit of length physically?

When we discuss about the wavelength of em(electromagnetic) wave's wavelength, It is meant we are talking about the tip to tip of the oscillation of electrical and magnetic field in physical space. ...
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Why does changing the permittivity of the dielectric within a capacitor not have any effect on the electric field opposite the plate?

Utilizing FEMM 4.2, I built a pair of simple parallel plate capacitors, however I oriented them so that the anodes of these capacitors faced each other. As expected, the electric fields of the two ...
3 votes
4 answers
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In metals, the conductivity decreases with increasing temperature?

I am currently studying Principles of Optics: Electromagnetic Theory of Propagation, Interference and Diffraction of Light, 7th edition, by Max Born and Emil Wolf. Chapter 1.1.2 Material equations ...
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2 answers
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How do charges in a circuit know how much work to do on a component?

So I'm a high school student learning physics so I don't really know much about circuits yet. Our teacher said that in a circuit, electrons don't really flow through the circuit and that there's more ...
0 votes
1 answer
155 views

Why is this incandescent light bulb working under water?

The bulb is directly connected to 220V supply and is put into this glass container containing normal tap water. Why is this bulb working under the water? What about the ionisation of water molecules ...
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Why do the refractory metals have the highest bond strengths out of all metals?

I am currently examining the refractory metals (mainly Nb, Mo, Ta, W, Re) and I wish to know why these metals have the highest bond strengths of all the transition metals, as characterized by their ...
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Experimental results for the measurement of Positron lifetime / Positron decay [duplicate]

It is assumed that the positron, being the antimatter particle of the electron, is stable. I am interested in finding experimental results or experiments which have measured the positron lifetime in a ...
23 votes
7 answers
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Is it wrong to say that an electron can be a wave?

In QM it is sometimes said that electrons are not waves but they behave like waves or that waves are a property of electrons. Perhaps it is better to speak of a wave function representing a particular ...
10 votes
1 answer
443 views

Why an electron and a positron should have the same lifespan?

According to Particle Data Group: source: data Particles and their antiparticles (i.e. antimatter) have the same lifespan. The electron/positron for example have a minimum of 6.6E28 yr. This was ...
3 votes
1 answer
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Magnetic field by a electron

In an atom there are $n$ electrons and the $n$th electron creates a magnetic field, as it has velocity and the other $n-1$ electrons will be affected by this force. But still, why aren't we ...
0 votes
1 answer
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Is mass defect of atoms considered when the mass of electron is measured within atoms?

First of all, here considering the mass defect as the binding energy between an electron and the rest of the atom; i.e. taking the mass of nucleus as it is. That since nuclear mass defect is present ...
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1 answer
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Behavior of electrons in a resistor

Imagine a circuit with a constant voltage and no resistance. Every electron would gain the same kinetic energy as it moves from the negative to the positive terminal. If we add a resistor to the ...
13 votes
4 answers
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Is Pauli's Exclusion Principle a restatement of what experiments have shown?

So were studying the configuration of electrons in an atom and one thing that popped up was Pauli's Exclusion Principle. In our class, as well as our textbook, it was stated as the fact that two ...
5 votes
4 answers
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Can particles at rest have wave nature?

Can particles have wave nature even when they are at rest? I think this is possible due to the formation of standing waves
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Landau levels in graphene - unbounded from below spectrum

Considering the case of monolayer graphene in a perpendicular magnetic field arises LL in it. The final spectrum is given by $$ \epsilon_n=\mathrm{sign}(n)\hbar\omega\sqrt{|n|} $$ where $n\in\mathbb{Z}...
1 vote
1 answer
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What range of light on the electromagnetic spectrum are produced by the de-excitation of electrons?

When an electron moves from an excited state to its ground state, a photon is emitted, which is the source of light. However, I know that the highest energy form of light, gamma rays, are produced ...
2 votes
3 answers
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How does an electron move in the $p$ orbital?

This is my first time learning about orbitals and I am very confused over how do electrons move around the nucleus in the $p$ orbital. Wouldn't it have to move out of the orbital where probability of ...
198 votes
14 answers
88k views

Why don't electrons crash into the nuclei they "orbit"?

I'm having trouble understanding the simple "planetary" model of the atom that I'm being taught in my basic chemistry course. In particular, I can't see how a negatively charged electron can stay ...
0 votes
1 answer
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Fermi Gas - Number of Free Electrons at High Temperatures

What I am trying to do is to compute the specific heat of a free electron gas in a conducting metal. I am using Fermi-Dirac statistics as my framework to build off of. Importantly though, I want to ...
3 votes
2 answers
300 views

Electronic component of the Hamiltonian operator and uncertainty principle

This question has to do with the concept of uncertainty principle. The Hamiltonian operator has the electronic component that takes the inverse of the distance between any two electrons. My question ...
1 vote
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What is meant by spin temperature in the context of ultrafast demagnetization's three-temperature model?

Ultrafast demagnetization and associated fields often refer to the three-temperature model introduced by Beaurepaire. As the abstract says: The relaxation processes of electrons and spins systems ...
1 vote
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How $e/m$ ratio depend on voltage?

I currently studied about Cathode ray experiment by JJ Thomson. In that as you know he found an $e/m$ ratio, where $e$ denotes charge of electron and $m$ denotes mass of electron. And this ratio is ...
1 vote
1 answer
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Difference between $e^-$ capture and $ β^+ $ decay

A nucleus stability is judged by it's n/p ratio, which it prefers to be ~1. If n/p ratio is much less than 1, an atom tries to increase neutrons and decrease protons present in the nucleus. My physics ...
2 votes
7 answers
270 views

How can current flow without voltage?

The following is an image from my school textbook How do electrons travel from E to F is voltage (or the J per C of charge) is zero? I think my issue is a deeper misunderstanding of the nature of ...
0 votes
1 answer
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Static electricity problem

Take the following diagram and explanation: I have two questions: Why is the table tennis ball with metal paint attracted to the positively charged rod. Although the negative charges move closer to ...
5 votes
2 answers
849 views

Non-interacting electrons

At the undergraduate level, in quantum mechanics, statistical mechanics, solid-state physics we always deal with non-interacting electrons. I don't understand why we take non-interacting, and how it ...
2 votes
3 answers
5k views

Fields of a moving electron

Suppose an electron is moving through empty space at speed v. It produces an electric field because it is a charge. But this field changes as it moves. Changing electric field must give rise to ...
1 vote
0 answers
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Can delayed choice experiment be observed live?

In delayed choice experiment an observer is added to observe the path of electron which results in interference pattern changing to clump pattern. So if the experiment is conducted live and if ...
1 vote
3 answers
223 views

Double slit experiment: Are electrons interacting with other electrons to create a wave?

Assume a double slit experiment with electrons and no observer (light source). Can the wave-like behavior and resulting interference pattern be explained by the single electron that is being shot, ...
0 votes
2 answers
376 views

In the photoelectric effect, what happens to the electron if the work function is too low?

I know that no electrons will be emitted from the atom if the threshold is not reached, but my professor is asking us what happens to an electron in this scenario. I asked if the electron would just ...
3 votes
1 answer
478 views

Opacity/transparency of conductive meshes to charged particles (electrons/ions)

When using a conductive (metal) mesh, effectively a metallic woven fabric, in vacuum applications as a "grid" for charged particle optics, how does one calculate (or at least estimate) the opacity or ...
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Is central field approximation perfect for alkalis?

In my atomic theory lecture notes it always says the central field approximation is 'excellent' for alkali atoms due to the spherical symmetry of the core electrons and the $s$-shell of the valence ...
0 votes
1 answer
203 views

Why electrons have spin one half?

Here I am asking about electrons, but of course this same question applies to muons and all the other spin one half particles. I am aware that spin is defined as "an intrinsic property" of a ...
2 votes
0 answers
269 views

Electron Beam Welding equation

I am studying for a nuclear physics course right now and came across a question and topic that sparked my interest - Electron Beam Welding. As I understand it, the process heats up the metal by ...

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