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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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78 views

How can electrons and quarks be composite?

There are theories suggesting that the electrons and quarks are not elementary particles, but instead are composite particles of two or more yet undiscovered elementary particles. However ...
15 views

What defines a material is an anode or a cathode?

How to know if a material is an anode or cathode? and if i connect an anode and a cathode will it be a diode? Like the pensil razor diode, if it worked not because of that, how does it work?
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What are the deciding criteria for occuring of reflection, absorption, Emission, refraction and burning? [closed]

Why does some objects reflect, refract, absorb, emit and burn, when electromagnetic wave is thrown on them? I want to know all these things at atomic and molecular level.
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How can the annihilation of an electron and a positron create a quark-antiquark pair or a muon-anti muon pair?

The overview of this interaction is that a positron and an electron annihilate with each other and create two gamma photons which contains too much energy and soon materialise into a quark-anti quark ...
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Eigenstates in a 2D metal disk with finite-size perpendicular magnetic field (Piece-wise Gauge)

Let's have a two-dimensional metal disk with radius R, and now I apply a uniform magnetic field B perpendicular to the disk, within the concentric part of the disk with radius r $\lt$ R. How can we ...
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Property of the time evolution operator preserving the norm of the wavefunction

Since the time evolution unitary operator preserves norm, if applied to any system say electron whizzing around its orbitals, no matter what time we consider would it always have the same probability ...
99 views

Frequency of light versus frequency of electron vibration

I've been trying to understand photons and light, although entirely conceptually (layman with not much of a background here, but I really want to understand this a bit better) and there's a couple of ...
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What exactly is a coefficient of friction due to electron stopping?

To be more specific, I am looking to understand what electron stopping is and how I could possibly define a coefficient of friction due to electron stopping. I am running MD simulations using LAMMPS ...
50 views

Treatment of electrons and phonons in condensed matter physics

I was watching the lectures by steve simon(oxford) on solid-state physics. In the course, he derived the dispersion relation for phonons(assuming spring between atoms) and dispersion relation for ...
23 views

What is the meaning of 'sputtering' in Ion pumps

So after reading a few articles this is what I understand: Air enters the pump through diffusion In the pump there is a cloud of electrons between two (grounded) cathodes As soon as an electron hits ...
41 views

What is occurring inside the lattice structure of metal when compression happens?

I was browsing reddit and saw this post. It is a gif of a factory, with a huge press squashing a hot chunk of metal. I'm specifically interested in the behavior that is happening after the initial ...
82 views

The mean free path of electrons in high vacuum is 26 billion kilometres?

I used this formula to calculate the mean free path length of an electron in high vacuum. $$\lambda = \frac{k T}{\sqrt{2}\cdot4\pi r^2 \cdot p}$$ where k is the Boltzmann konstant, T the temperature ...
70 views

Does a relaxing electron really accelerate?

This is not a duplicate. I am not asking about quantum leaps or quantum jumps or whether the transition is instantaneous (yes I asked that question before here Do electrons really perform ...
45 views

Query about Heisenberg uncertainty principle

acoording to heisenbergy uncertainty principle if the electrons change the radius of their orbit, then it is like making transition even though the change in radius is small and they should emit ...
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What is the nature of the multipoles used to shape/re-direct an e-beam?

Imagine having an electron beam, just like in an electron microscope. Now imagine that we have some multipoles prepared in the beams path to influence the shape/path of the beam. My question is: ...
334 views

How did we know that the Dirac equation describes the electron but not the proton?

I'm suddenly getting confused on what should be a very simple point. Recall that the $g$-factor of a particle is defined as $$\mu = \frac{ge}{2m} L$$ where $L$ is the spin angular momentum. For any ...
28 views

How would a electrostatic lens accelerate a continuous beam of electrons?

Truthfully, I am somewhat confused by this topic. Electro-magnetic lenses are created by coils, through which one runs a current, which then in turn generates a magnetic field whose field lines are ...
18 views

Electrons' distribution inside bands

If you consider a crystal of silicon made by $N$ atoms, you know that there will be a valence band with $4N$ possible levels of energy for electrons and a conduction band with $4N$ possible levels of ...
32 views

Difference between discharge tube and capacitor

I did search this on google but didn't get satisfactory results. Can you tell me difference between capacitor and discharge tube? "**Discharge tube has its gaseous medium at very low pressure but ...
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In non-technical terms, how does the scanning electron microscope function?

I've watched a few videos like this one and know the basic structure. We have an e-source, an anode which pulls electrons out, then a condenser which starts to focus all beams, scanning coils and ...
203 views

Are electromagnetic waves only caused by accelerating charges?

Like the title says, are electromagnetic waves only caused by accelerating charges? Are there any other methods for the generation of photons? If electromagnetic waves are ONLY able to be created by ...
1k views

Is there a magnetic attraction between two parallel electron beams?

I am refering to Ampere's force law, and to the beams accelerated after the cathode, so the deflection is not due to their respective cathode. In other words, do two electrons accelerating parallel to ...
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Identity reversing event

I'm a master student in mathematics currently taking Quantum Mechanics and since the lecture notes provided by the lecturer aren't cutting it I'm reading "Quantum Mechanics and Path Integrals" by R. ...
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Is the falling back to ground state of an electron what makes the electromagnetic wave, or is it the action of absorption AND falling down?

When an electron absorbs a photon, there it accelerates and thus it creates a kink in its electric field. Then, when it falls down to its normal state, it creates another kink. Here are my questions. ...
77 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 ...
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Are electrons in a singlet state still electrons?

Given that some interactions such as electron capture make the electron "disappear" and the output fermion is a neutrino, I wonder what is the rationale behind saying that in the case of two opposite ...
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Do electrons in the same orbital but different spin feel each other's Coulomb repulsion?

Or is it irrelevant, as orbitals are QM while Coulomb interactions are classical physics? What I think I understood of orbitals is that particles with the same quantum numbers cannot occupy the same ...
5 views

Does an electron spin axis form a characteristic angle with the direction of its translation?

I looked everywhere I could think of but found no connection between the orientation of the spin and the motion of the same particle. So maybe there is none. Yet, in the case of an electron being ...
14 views

diamagnetic substances and experimental support of electron configuration

In a basic explanation I have read regarding apparatus used to show the electron configuration of a material's atoms, it states that diamagnetic substances when weighed in the presence of an external ...
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How an ultra-relativistic electron near the speed of light keeps its spin velocity without becoming partially superluminal?

If an electron has spin and volume than the point on the surface is rotating at constant speed according to Planck constant defined angular momentum.If this electron accelerates then this point on the ...
49 views

Left and right handed electromagnetic radiation from different subatomic particles?

The acceleration of electrons in an antenna rod produces a radio wave with its oscillating electrical and magnetic fields. For a vertically oriented rod the electric field points up- and downwards. ...
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Is the acceleration produced by electrostatic repulsion quantized?

Say the universe at time $t_0=0$ consists of two electrons at rest, both of charge $q$, separated by some distance $r$. The repulsive force $F$ between them is $F = C q^2/r^2$ where $C$ is Coulumb's ...
39 views

Is electron capture partially responsible for matter decay?

Sorry for the very likely ill-posed question. I have lately started reading a lot about quantum physics and the nature of electrons and I read about a phenomenon known as "electron capture" which can ...
38 views

Intuitive explanation why electrons move from low to high electric potential

I know almost nothing about physics but am about to learn some electronics. I have trouble understanding why electrons move from low to high electric potential based on the definition given on the ...
61 views

Can we add the resistivity due to different scattering mechanisms?

Suppose there's a metal in which electrons interact with themselves and with the phonons. The hamiltonian might look like this \begin{equation} H= \sum_{k}\epsilon_k c^\dagger_k c_k + \sum_{k}\...
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Forces in the equilibrium state of a molecule

I'm trying to minimize the energies of hydrogen molecule and lithium hydride molecule with the L-BFGS method and HGH pseudopotential, see arXiv:cond-mat/9803286. Hydrogen molecule works fine but ...