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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In a copper wire, how many electrons does each atom give away?

As an ion, copper can give off 1, 2, 3 or 4 electrons. But it has 1 s electron in the last shell and 10 d electrons. So as a metal, how many of those are delocalised and free to move around, and how ...
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Why does the Anode and not the Cathode corode during eletrolysis of water into $H_2$ and $O_2$?

After experimenting with the production of Hydrogen from salt water, I kept on noticing that the Anode (-) gets coroded and not the Cathode (+). Is it perhaps that water in itself is a naturaly ...
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790 views

Diffusion and Drift currents in forward bias

Why do the current in diode in forward bias configuration called "Diffusion current" even if this current is a resultant of external voltage supply which create electric field in diode ,hence should ...
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60 views

Explaining Lenz's law?

This example given bellow intrigued me, since it is really simple but I still can't find it coherent with experimental results. Description : We have a static magnetic field pointing in the $\hat{x}$ ...
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129 views

How does an electron qubit work?

Imagine a qubit, whose physical support is an electron. If its information is the spin, how could we change the spin of the electron? It can have two spins, so I thinks that to change it, you have to ...
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29 views

Energy level/shell version of the conduction band in a solid?

As far as I know, the isolated version of the valence band is the valence shell, so the isolated version of the conduction band should be conduction shell? As electrons in a lattice that are exposed ...
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81 views

Spin-orbit coupling in itinerant electron systems

Itinerant electron systems are, e.g., metals. The electrons are not anymore localised at the atomic nucleus, but they behave as Bloch waves, which have a non-neglecting probability of travelling ...
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140 views

Can two lasers ionize a single point of air?

I am not very educated in this subject, so I apologize in advance if what I am asking is obvious/incorrect/duplicated. I am interested in volumetric displays, and was doing some research when I came ...
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29 views

Orbitals and configurations with degenerated energy

When we have to choose, given $n$, $\ell$, where to put an electron, when there are several $m$ orbitals, with the same energy, is there a concrete quantum mechanic rule or some superselection rule to ...
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321 views

Strong material but transparent for high energy electron beam

I'm looking for a material which is strong enough to cover a 2mm hole between two chambers with one containing a ultra high vacuum and the other atmospheric pressure and at the same time it should be ...
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98 views

What is the velocity distribution of electrons in the suns core?

I am given a problem where the temperature of the suns core is given and I have to calculate the average speed of an electron in the core. The only thing that pops into my head would be the Maxwell-...
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251 views

Why electron and positron annihilate would produce hadron (jet of gluon)?

Electron (fermion) is an elementary particle just like positron and they interact via boson which is photon, electromagnetic force. I like to know why is gluon (hadron) being emitted when electron and ...
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2answers
80 views

Does the Conventional Current flow consist out of anything? (virtual photons)

I've red that virtual photons are a way of interpreting the electromagnetic force between charged particles. Is convention current a electromagnetic field or force? Or is it a movement of ...
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49 views

transmission electron microscope beam divergence (limits on resolving power)

I have learnt about TEM recently and have a few questions. I've searched all across the internet but can't find the answer to whether or net electrons in the beam will repel each other thus diverge ...
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1answer
61 views

Instability of electron gas

I am trying to understand the following statement from notes which I found: "For electron gas with long-range Coulomb interaction there is a problem with its instability". What does it mean? I know ...
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1answer
88 views

For the ground state of tin, why is it not possible to have a triplet D state?

I have been looking at electron configuration and understand the use of hund's rules, the Aufbau principle and the Pauli exclusion principle but am having difficulty with a question that has come up ...
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45 views

Does valence electrons have restricted spin?

For a valence electron in Antimony Sb with the electron configuration: $Kr(5s)^2(4d)^{10}(5p)^3$ The 3 valence electrons have the quantum numbers $n=5,l=1,m=1$, resulting in the following ...
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108 views

how to electrically charge object like comb

I know we can electrically charge comb my rubbing against hair which in turn will attract paper pieces. But is there way to charge object e.g. comb automatically. e.g. using battery or something. So ...
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62 views

How ionized is the plasma in a Crookes tube

How ionized is the plasma in a Crookes tube, at $10^{−6}$ to $5 \times 10^{−8}$ atmosphere ($7 \times 10^{−4}$ – $4 \times 10^{−5}$ torr or 0.1–0.005 pascal). Under any of these circumstances is it ...
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105 views

Time dependent perturbation from Galilean transformation

I'm having a little trouble figuring out how to start this. The question is as follows. At time $t<0$ a hydrogen atom is in the rest frame $\mathfrak{R}$. Then at time $t=0$ the atom suddenly ...
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1answer
60 views

Electron in its orbital

I was just wondering online about as in how does an atom actually look like and I stumbled upon a page that discussed the matter. However, the statement We sometimes say the orbital describes the ...
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1answer
35 views

Are free electrons in an ideal conductor unbound to the atoms?

If an ideal conductor moves without its position or geometry changes, will the electron sea remain at its previous position (because it is not compressed or anything that causes a regulation effect)? ...
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652 views

What is the fundamental difference between heat and electricity?

When I had some basics of physics in high school, I learned from my teacher this: There are two types of energy transfer - heat and work. If the heat is reflected in a temperature change, it is ...
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2answers
44 views

Foil/material that is invisible to electrons but not to infra-red

I'm wondering if there is a material, probably existing in a foil or sheet form, that is absolutely invisible to electrons but not to infra red. This material should not have any interaction with ...
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77 views

Why are oil drops' charges quantized on a large scale?

Recently, I've carried out a Millikan oil drop experiment. It was a tiny experiment I only recorded three droplets. I calculated the 3 charges of the droplets to be approximately $q_1=86.6\ e$, $q_2=...
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84 views

Transient reflectivity of metals at infrared energies

The transient reflectivity of metals in pump-probe configuration has been extensively studied but, to the best of my knowledge, with a pump energy lower or equal than the probe energy. I tried to find ...
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2answers
315 views

Where are the electrons of a cathode ray tube coming from when using AC?

I see in this picture a beam of electrons leaving the cathode. But I read before, that the electrons can flow out of a copper wire only, if they are replaced by other electrons. I guess, that in the ...
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49 views

Photons projected towards corner, What next ? ( Uncertainty principle in bound region )

There are series of events that led to the query - First what I was wondering is what happens when light falls in the "corner" of a perfect ( reflecting ) substance like the corner of a cube. Then I ...
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40 views

What causes kinetic force in a collision?

Okay, I'm not a physics person and know next to nothing about the subject, so I apologize if this is a stupid question. I was wondering about something. It's an accepted fact that two solid objects ...
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133 views

What happens to an electron which falls into a black hole?

I was thinking about this for a while. The tidal effects due to strong gravitational fields will "spaghettify" something that falls into a black hole. But, electron is a fundamental particle. So, what ...
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151 views

How can the Fermi level be in between the band-gaps?

This isn't a duplicate of What does Fermi level in the band gap mean?. I read it and I'm still confused, and moreover I'm not allowed to add another comment to it anyway because I don't have enough ...
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106 views

Observing particles without photons

Can particle physicists in a lab observe a particle, with electrons orbiting, in a vacuum without putting a photon on it (without inserting any electromagnetic energy so we don't disturb the position ...
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49 views

Can the MSW effect be modified by non-standard neutrino-neutrino interactions?

The MSW effect describes how propagation of neutrinos through matter can resonantly enhance the neutrino mixing. The reason for this enhancement is that the presence of electrons in matter changes the ...
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46 views

Electron confinement: has it been done in the lab?

Has electron confinement been done in the lab and is it possible to confine a proton like we do to an electron.
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29 views

Determination of electrons flow through the crystal

Talking about doped semiconductors: Atoms outer shell extends and overlaps with another ones outer shell (the conduction band), right? So when electrical field is applied to a semiconductor bar (lets ...
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222 views

Nature of metallic bonding in solid state

What is the reason behind attraction of metal kernels & free electrons in electron sea model?
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1answer
99 views

What is the phase velocity of light in graphene?

This article states that light can "slow down by a factor of a few hundred" when it strikes graphene. I've read elsewhere that the index of refraction of graphene is about 2.65 + 1.27i. According to ...
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98 views

What happens if a photon emitted from an electron hits a positron?

Assume electron and positron are free particles, I think the emitted photon will become left or right circularly polarized depending on the sources. Am I just being paranoid or does the photon care ...
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73 views

Has the Pauli Exclusion Principle been renamed? If so, what is it now called?

The force of touch is actually an emergent phenomenon that results from a complicated interaction between electromagnetism, and a feature of quantum theory originally called the Pauli exclusion ...
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1answer
27 views

What is the deflective efficiency of glass?

If I have ions, electrons, and gas particles bouncing off of glass, how much energy will the particles retain? what % of the energy will be be retained what % lost, the particles I am referring to are ...
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43 views

What is the formula for the wavelength of radiation produced by non-relativistic electrons travelling through an undulator?

Is it simply equal to the length of the undulator periods? Or does it depend on the electrons' velocity and the strength of the magnetic field? Thanks.
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The structure of the electron as a particle

has anyone found the minimum radius of the electron including the magnetic field ( dipole moment) ? The 'classsical' radius only uses the electric field, and so is a minimum radius for a purely ...
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2answers
467 views

Degeneracy of two electrons on a ring

The one-particle solution to the particle-on-a-ring problem is $\psi_m(\phi_j) = \frac{1}{\sqrt{2\pi}}\exp\left(-im \phi_j\right)$ for $m=0, \pm 1, \pm 2, \cdots$ corresponding to energies $E_m = \...
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Electron Hopping Between Ions of Molecule

I am trying to determine the Hamiltonian in matrix form of a single electron which can move between six ions of a molecule. The basis $|e_j\rangle$ represents the electron being present on the $j^{th}...
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How can we be using the orbital model to calculate such microscale phenomena as Zeeman effect?

Surely it begs for a quantum-mechanical description? Thank you.
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Acceleration of electrons from Cooper pairs and EM radiation

For the question What makes Cooper pairs of electrons so fit for an unhindered current through a superconducting wire? where was a nice comment from CountTo10: Assume any photons are effectively ...
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659 views

Electron Levels of Atomic Nitrogen Vs. Molecular Nitrogen

So I have a question about the the affect of the electron energy levels of Nitrogen when it becomes diatomic. In Figure 1 below you see the electron energy levels of atomic Nitrogen, and it shows that ...
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Equations for numbers of conduction electrons in metals? How to calculate?

I need help understanding these equations from Fundamentals of Physics, 8th, Halliday & Resnick. The book doesn't use symbols for the equations, which makes them hard to follow. I understand ...
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What makes electrons land so strictly scattered after passing through a hole, slit or double slit?

In this video you can see electrons landing on a receptor and building up an interference pattern after passing through a (nano-size) double slit screen. I have read about diffraction and interacting ...
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275 views

Difference between ionization and scattering of electrons

My question is rather simple but puzzles me altogether. I'm just studying electron stopping power and I see in few graphs (particularly fig. 30.11 in PDG booklet) that Moller and Bhabha scattering are ...