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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Threshold frequency in photoelectric effect [duplicate]

If I take a metal sample and I throw light on it, and the emitted photons have frequency less than the threshold frequency required to make an electron come out of that particular metal. So the ...
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Weak hypercharge physical existence

How do we know that electrons are chiral? Even if left-handed electron carries weak hypercharge, it's only for an infinitesimally small time or is it predicted by QFT?
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Deriving effective interactions, e.g. phonon-mediated electron-electron interaction

Upshot of the question: how can I derive the effective electron-electron interaction brought about by the electron-phonon interaction? I've read derivations of the electron-phonon interaction and ...
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What is the atomic number of an electron, and why is its symbol $\sideset{_{-1}^{\phantom{-}0}}{}{\text{e}}$ in $\beta^{-}$ decay equations?

I'd assume that the atomic number, i.e. the proton number, of an electron is $0$ given that it doesn't have any protons. However, to balance beta minus decay equations, this source seems to claim ...
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My hairs on my hand stand straight whenever I move my hand to TV screen and feel vibration and sound on TV screen

Whenver I try to reach my hands near the screen of my TV . My hairs on my hands get straight and more importantly I can hear and feel a sound and kinda vibration . Please mention if this sound ...
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Physics question on effect of magnetic field on cathode rays in a cathode ray tube

My question is regarding the direction in which cathode rays bend in a magnetic field. My book states that : When only electric field is applied, the electrons deviate from their path and hit ...
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Free electron laser has really free electrons?

I have read this: https://en.wikipedia.org/wiki/Free-electron_laser This states that electrons are free. Now there is a debate on this site over whether a truly free electron in vacuum can or ...
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Why electron can go through PVC insulator

I connected a PVC insulated alligator clip test lead to a 12V (give 20V) DC power supply positive terminal and a multimeter. After that I connected an other one to the multimeter ground, and a third ...
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What happens to the electron when a neutron knocks off a proton from hydrogen atom?

In recoil proton scintillators, the hydrogen acts as a neutron converter to produce protons when a neutron strikes a H atom. But what happens to the electron in H atom? Where does it go? Does it ...
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Ways to limit interaction volume in a SEM without changing e-beam energy (spot size)

All I can find online is that the interaction volume of a scanning electron microscope is affected by e-beam energy, angle of penetration, and sample composition. Are those really the only things that ...
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How do you combine wavelengths of particles in an atom?

As the problem below results in the wavelength of a single electron, how would this combine/interact with other particles? In an atom, for example.
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Energy levels of electrons in an arbitrary element?

Let's say I want to calculate the wavelength of the photon emitted when an electron of an arbitrary element (let's say Carbon) drops from $n=4$ to $n=3$. Correct me if I'm wrong, but I think I would ...
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What does the Heisenberg principle actually mean? [duplicate]

As far as I can understand, the Heisenberg principle limits the possibility of calculating the exact position and momentum of electrons, as the light we use to observe it changes it's velocity. But ...
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Are the microwaves in an ECRIS plane polarized?

Or randomly polarized? Are the photons in phase, like in a laser or maser? What is the theory behind how an electron in an ECRIS responds to a microwave photon?
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How can electrons travel from the valence band into the conduction band?

I'm currently studying Introductory Semiconductor Device Physics by Parker. In band-theory, we know that if an electron is at the top of an energy band, then there are no allowed states immediately ...
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Rutherford's and Bohr's model of atom [duplicate]

Rutherford's model of atom was ruled out because it failed in explaining stability of an atom. Since any particle that is accelerating continuously emit radiation. And in case of an atom eventually ...
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Electrons in a conductor loosely bound or delocalised (as per QM)?

Currently there are two main ideas of those electrons that move in a conductor: those electrons moving are loosely bound to the valence shells of the atoms in the lattice those electrons moving are ...
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Wave function evolution of an electron [closed]

In many basic quantum mechanics books the wave packet of an electron is described. It will say that the wave packet will broaden as time evolves because of dispersion. But suppose the electron just ...
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Is there a resolution limit to electron microscopes?

Is resolution limited only by the wavelength of the electron? Because then I would presume there is no limit to resolution as you could lower the wavelength of an electron by increasing the voltage of ...
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How does electricity travel near the speed of light if electrons drift at a snail pace? [duplicate]

I was in a reddit argument with someone who said electrons didn't flow at the speed of light in a circuit. Then he linked the Wikipedia page for drift velocity and defeated me in one fell swoop. Now, ...
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What is energy band gap?

Explanations for graphene's high electrical conductivity often discuss energy band gap. What is energy band gap and how does it relate to the conductivity of a material?
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Question about the integrity of a TEM analysis result

I have a question concerning the integrity of a particular TEM analysis that was done. The specimen was household dust that may or may not have contained asbestos, and was sampled with Ghost Wipes, ...
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Double Slit Experiment : Photon vs Electron

are the following statements correct: For Young's double slit experiment with electrons, the separation between two slits has to be smaller than the position uncertainty of the electrons. But no ...
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Why does electron $(-)$ keep rotating round the nucleus $(+)$ even they are attracted? [duplicate]

I'm a secondary school pupil, my physics textbook discussed atomic physics without deep details because we are young boys, to explain electron motion we first learn about rotational motion. The main ...
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electron free mean path understanding

I am having difficulties to grasp the idea that the probability a particle is absorbed between $x$ and $x + dx$ is given by $$dP(x) = \frac{I(x) - I(x+dx)}{I_0} = \frac{1}{l} e^{-\frac{x}{l}}dx$$ ...
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Are Electrons in a Circuit Subject to Newton's Third Law?

Consider a simple electrical circuit made up of a battery, an incandescent bulb, and wire. The battery and bulb are equal in mass and are on opposite sides of a circle made up by the wire. Lastly, the ...
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Do positrons have electric dipole moments?

Is there experimental evidence checking to see if the positron has an electric dipole moment at rest? Or has an experiment measured it’s magnetic dipole moment at rest?
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Can't we see electrons without affecting their movements? [closed]

Can't we see electrons without affecting their movements? I was thinking about the double slit experiment and something is writing on Feynman's book like photons can affect their movements too. But I ...
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Free Electron-Bond Electron Interactions

I am reading an introductory textbook on electronics: Practical Electronics for Inventors by Paul Scherz and Simon Monk. In a section discussing the motion of electrons in circuits, the textbook ...
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How are free electrons reincorporated into orbits?

In particular, I'm curious about what happens to beta particles once they lose most of their kinetic energy. As I understand, they'll eventually find their way into orbits of surrounding atoms, but ...
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Under which condition the drift velocity stops increasing proportionally with respect to the electric field

Our professor asked us a question the other day but i wasn't able to figure it out. If we increasing Electric field then drift velocity will increase, Because of this Equation: Vd = μ * E But at ...
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Why alternating current produces electromagnetic waves? [duplicate]

So my question is: why alternating current produces electromagnetic waves? There are plenty of answers on google that state it as fact, but none answer why. I mean what is it about accelerating ...
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Are all collisions involving photons and electrons elastic?

In my textbook it asks me to calculate the energy gained by an electron that scatters an incoming x ray through a given angle. Using the Compton scattering equation you can work out the change in ...
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Question about the diffraction of electrons

This question concerns the diagram on the left. This is the set up. My question is that, why is collector current not an increasing function of the KE of the electrons? I can understand the graph ...
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Color of Every gas should be white?

The reason why halogens are coloured are because they absorb visible light and their electrons get excited to higher States this result in visibility of the complementary colour But when an electron ...
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Single atom in an ion trap [duplicate]

I have seen this photo in a lot of articles which is described as picture taken of a single atom in an ion traphere's the link to one of them. I find this very fascinating, but i still can't ...
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Why is a maximum value of current observed in Davison and Germer's experiment?

While studying matter waves, we were discussing Davison and Germer's experiment on electron diffraction when we learnt that a maximum value of current (measuring the intensity of electron diffraction) ...
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Why and how do holes in the valence band of the p-type material of a p-n junction diffuse through to the valence band of the n-type material

tl;dr -- See the question title I quote from this Wikipedia article on the depletion region: By definition, the N-type semiconductor has an excess of free electrons (in the conduction band) ...
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Elastic electron scattering

In an electron diffraction pattern, the elastically scattered electrons are distributed over resolutions in the pattern corresponding to resolutions considerably higher than 1 Å. What does this ...
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Why does a scintillator need to be fast decaying?

I have two scintillators, say, one with a decay time of 1 ns vs. one with 100 ns. All other parameters like light yield, size of crystal, electronics used, source emission rate, are the same for both. ...
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Question about point particle vs. wave equation location

Another uncertainty question, this came up in another forum. As I understand it an electron, for example, is a point-like particle. I take this to mean it exhibits dimensionless properties, but ...
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Brehmsstrahlung radiation query - If an electron is constantly being decelerated, how does it emit a photon with a fixed energy?

According to my textbook they simply say an electron is decelerated by a nuclei and this means it loses KE. The difference in KE is given off as a photon. But an electron is always being pulled back ...
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Generating random position for electron within 3D orbitals

Apologies in advance if this is the wrong StackExchange to ask this question in... if it is not, please don't just down-vote, let me know where else to go and I will gladly. I'm just trying to learn. ...
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Chemical bond in diodes

Well I have seen diodes with many breakdown voltages. How is this possible ? I mean when an electron fills a boron hole it a bond is created between the boron atom and the nearby silicon atom.Well in ...
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Electrons flow in Circuits

The electric field created by a battery through a section of wire in a series circuit is constant. This means that the force on each electron as it travels through the wire is constant. According to ...
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What actually current is? [closed]

Somebody help me visualizing current. What is it actually? Not just with mathematical relations but with something that we can visualize too.
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Claim of high order electron-electron repulsion

A member of staff at uni once claimed in an interdisciplinary seminar that electron-electron repulsion can be to the 11th power of the reciprocal of displacement. I have tried to find this mentioned ...
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How do we know how much charge is in an object?

It's a little science history question but I really wonder how did peoples measured the amount of charge in an ball or something or like in coulombs case how did he measured the electrical force ...
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Do electrons exist in shells or can they be found existing as an individual?

I am just a high-school student trying to self study,please excuse me if the question sounds silly to you. A simple question: Are electrons always found in orbits/shells of can they even exist by ...
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Why do we use dielectric materials in a capacitor?

Okey first of I know dielectric materials used in capacitors to insulate and polarize due to electrical field created by two metal plates and then when you connect this stored energy to a system you ...