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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39 views

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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53 views

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 ...
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What would have happened if electron was considered positive?

We always keep on telling that current flows opposite to electron, since electron is negatively charged. And old people didn't knew, that it is electron which actually flows.. So, now if we correct ...
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Experimental Assignment of Electronic Transitions in Atoms (Grotrian Diagram)

Grotrian diagrams often taught in instrumental methods of chemical analysis to chemists. After a decade, I finally found the original book of 1927 by Grotrian "Graphische Darstellung der Spektren von ...
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Why protons and electrons attract each other? [duplicate]

This YouTube video states that electrons and protons are bonded together by emitting electromagnetic waves and absorbing each other's electromagnetic waves. But isn't because it due to potential ...
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1answer
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Are there ways to detect/measure photons that don't involve electrons?

As per question, are there ways to detect photons, and/or to measure their energy, that don't involve any interaction with electrons? And if yes, are there detectors which use photon interactions with ...
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What is the minimum distance between an electron and a positron so that they do not annihilate? [duplicate]

What is the minimum distance between an electron and a positron so that they do not annihilate? I want to assume that the location of an electron can be determined with an accuracy of 0.004 Angstroms,...
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Why does this quiz question say that protons and electrons do not combine to form neutrons?

I read this somewhere: Where are the protons and electrons in a neutron star? When the neutron star forms, most of the protons and electrons combine together to form neutrons. But on a true/false ...
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One Electron Universe - Bumping particles back in time? [closed]

I understand that John Wheeler's 'One Electron Universe' proposal is not generally accepted, but it's obvious that in disproving such a proposal, or at least discrediting it, we can gain insights to ...
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Electron density in DFT (*ρ*(r)) and probability density (wave function squared)

Are the electron density in density functional theory, ρ(r), and probability density, defined as wave function squared, the same quantities?
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Finding the value of $r$ for which the radial function, $P(r)$, has a maximum? [closed]

In my (university) particle physics course, I am asked to find the values of $r$ for which the function $P(r)$ of a $2s$ Hydrogen electron has its maximum values. Here, $r$ denotes the distance in ...
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What does degeneracy and multiplicity in Term symbol mean?

$^{2S+1}L_J$ was the term symbol. I watched a video online saying $2J+1$ was the fold of degeneracy to the term symbol. Specifically, for nitrogen, the term symbol for the lowest energy was $^4S_{3/...
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Why do atoms emit a certain colour of light? (The emission spectra)

We were taught about the emission spectra in class last year, but my teachers couldn't give me an answer to 'what determines the colour of light emitted?'. (they were giving me the answers to the ...
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How looks the “overarching” wavefunction of a number of electrons in an insulating sphere?

I changed my question after reading the comment of Anna. If we put a huge number of electrons inside a non-conducting sphere, what will the total wavefunction describing all electrons look like? I ...
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'Why don't electrons accelerate in a circuit' Confusion

https://physics.stackexchange.com/a/18806 Apparently he said 'at the same time', so when the electrons are 'pushed' by the electric field it is 'blocked' by the resistance simultaneously, if he said ...
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Does hydrogen reflect all visible wavelengths other than the wavelengths it absorbs?

I'm confused how reflection and absorption of photons work. For example hydrogen absorbs 4 wavelengths of light, but then that energy is emitted once the electron falls back to its ground state. So ...
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Why wouldn’t electrons in a CRT just get attracted to the accelerator anode?

I was wondering how the accelerator and focus anode in a CRT don’t attract electrons but they just focus and accelerate it? Why don’t electrons stick to it if they have a high potential?
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Why does 'The electron density builds quadratically with distance from the nuclues.'?

I found the statement above on this useful website. http://photonicswiki.org/index.php?title=Atomic_Orbitals_and_Nodes But I am confused. Why would that be the case? Is this based on some exotic ...
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Infinite vs Finite dimensional Hilbert space

Let us consider an electron in an infinite square well. As we know that the electron has a spin=$1/2$ . The spin operator ($z$-direction) has two eigenvectors which span the vector space. But if we ...
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Why do atoms tend towards electrical stability?

If an oxygen atom has six electrons, then it has an unfilled orbital and the oxygen atom may share electrons from two hydrogen atoms (and form water) in order to become more stable. But why does ...