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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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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 electric potential difference from the theory of states

A school of thought in Physics believes in understanding potential difference as a difference of states or energy levels at two different points. What should be the definition of potential difference ...
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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?

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? [on hold]

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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1answer
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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 ...
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1answer
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Why does previously rotating DC Motors not generate sparks?

Yesterday I was playing around with a small DC Motor ,(ones which you can find inside a toy) and found something interesting. I took a cell and fixed one terminal of the cell to a terminal of the ...
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Photoelectric Current [duplicate]

Recently learnt that Intensity= nhv ; where n is the number of photos per unit area My textbook specifies that the photoelectric current only depends upon the number of photons striking per unit time ...
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Path to ground / Source in AC circuit

I'm a 1st year EE student and i'm trying to get my head around earthing systems at the moment and could do with some help. The first thing that i'm struggling to understand is how current establishes ...
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Interference patterns of the orbital electron wave functions [duplicate]

I am new to this site so please forgive my initial errors of form or protocol. It has been fascinating to read the many explanations of why electrons don't "fall" into the nucleus and how we need to ...
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1answer
55 views

Power absorbed by electron in plane electromagnetic wave

How can the power (in Watts) absorbed by the electron be calculated, knowing the incident electric field amplitude $ E_0 $, wavelength $ \lambda $, and the electron momentum relaxation time $ \tau $ ...
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2answers
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Can an electron of an atom be found anywhere? Does it need energy to happen? [closed]

According to quantum mechanics it should be possible. But can it happens when it has so small probability to occur? also if it can happens that means that energy must be provided in order to the ...
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How does an electron know whether a photon is of correct energy states? [duplicate]

Since to become excited an electron in its ground state have to absorb a particular frequency of light otherwise they will just pass through each other, I'm thinking how can the electron measure the ...
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3answers
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What happens to the spin when photon is absorbed by an electron?

Photon is spin 1 and electron is spin 1/2, so when a photon is absorbed by an electron it is destroyed and the electron becomes excited by that amount of energy. The next moment the electron will go ...
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Shape of electron [duplicate]

Today, in the BBC Science section, a headline reads that the Imperial College of London has determined that the shape of the electron is completely spherical. In a physics book I'm reading now, the ...
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3answers
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Why can't we have charge field?

I learnt that everything is made of field, there is the electron field that occupy the entire universe and it will produce an electron which is an excitation of the field. This electron interacts with ...
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How would a difference in electron and proton charge be detectable in astronomy?

How would a deviation in neutrality of matter affect astronomy? Obviously this would introduce a lot of repulsive force but how, exactly, would that affect the universe? If the repulsive force was ...
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1answer
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Do electron really experience any repulsive force while attracted by proton compared to positron?

I read up that the reason 2 electrons with same energy states can be binded to the first orbital of a necleus is due to one electron having positive spin half and another having negative spin half ...
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1answer
29 views

Explain the equation describing total energy of the electrons in HET

I have this equation describing total energy of the electrons in HET (Hall-effect thruster): $$\frac{\partial (\frac{1}{2}mn(v_{ex}+v_{e\vartheta})^2 + \frac{3}{2}nT_e)}{\partial t}+\frac{\partial (\...
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1answer
60 views

How does the negative energy solution to the Dirac equation predict the antielectron?

Please, can someone explain how the negative energy solution can be used to predict the existence of the antielectron?
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2answers
28 views

Create a square well potential for an electron in practice

If my particle is an electron, how do I create a square well potential (in one dimension) in practice? I would like to know how to actually achieve it. Is it like at both the ends, I need to put some ...
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1answer
32 views

When two wires touch, electrons can flow from one to the other. Is that a metallic bond?

If two very hot wires touch, they melt together to form one wire and electrons can flow between them. If two cold wires touch, they do not melt together to form one wire but electrons can still flow ...
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Can you fake protons with light?

I have been reading similar discussions on how protons and electrons interact, using virtual photons and such. Yet, I can find little information regarding the subject in question. Can a beam of ...
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2answers
173 views

Voltage Drop Explanation. Is it correct?

When the battery is turned on, a wave propagates within the circuit to determine the current of the sytem.At this point, the current is inhomogeneous withing the circuit(but this dissapears almost at ...
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1answer
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what happens to an electrons orbital when it absorbs a photon

so I just learned about orbitals and hybridization theory through youtube and I have one question. if I have a hydrogen with one electron, the electron is in a 1s orbital, but then if that electron ...
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2answers
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What is the difference between a neutrino and an electron neutrino?

So, what is the difference between a neutrino and an electron neutrino? Like how does the term 'electron' made a difference? Also, what is the difference between an antineutrino and an electron ...
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How far do electrons actually move along a conductor under an alternating current?

This is more or less a curiosity question. But I have had really good luck with stack exchange so far. If I can expand on my question a little bit - it may not be super important, but I know under say ...
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1answer
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How was the electron in Rutherford's model producing a continuous spectrum and not a line spectrum?

How was the electron in Rutherford's model producing a continuous spectrum and not a line spectrum? What is the logical thinking behind that it will produce a continuous spectrum?
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1answer
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What happens to the $3d$ and $4s$ levels during the ionisation of a transition metal?

I'm just wondering about the transition state of a transitional metal before (ex: $[\mathrm{Ar}]\, 3d^3 \,4s^2$) and after ionisation (which means $[\mathrm{Ar}]\, 3d^3 \,4s^1$) because before ...
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3answers
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Quantization of electrons' angular momentum in atoms and molecules

It is known that the Schrödinger's equation of the electron's wave function in atoms can be solved analitically only when a single electron is present (the "hydrogenlike atom"). In that case, the ...
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Energy of electric field in the space between a pair forming a dipole

I'm not studying physics, I was just curious that if the electric field created by electron and positron in a dipole follows the same rules as double slit experiment. That is, for example on the ...
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1answer
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How are free electrons produced in a gas?

I'm aware about ionisation but even to ionise a gas you need an electron. So how in a discharge tube, which has a low pressure gas and a high voltage, does current flow? How is the first electron ...
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1answer
38 views

Can a strong electric field cause the electrons to come out of the atoms?

Can a strong electric field cause the electrons to come out of the atoms, is this how free electron are obtained in a discharge tube?
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1answer
49 views

Don't matter-antimatter annihilate each other completely releasing energy as photon?

Matter and antimatter should annihilate each other completely releasing energy in the form of photon, however it is discovered that smashing electron and positron together can also spew out higgs ...
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3answers
202 views

How is the envelope of a wave derived from the wave equation?

I'm reading this book about electrical properties of materials where the electron is introduced as a wave. Using the equation of a wave, they bring about the "envelope" of a wave. So here is how the ...
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4answers
193 views

Could an electron enter the nucleus, and if so would it be captured by a proton?

I've been trying to find an answer to this question, but have come across contradictory answers, and have limited knowledge of quantum mechanics myself. Almost all the threads (here and on Quora) ...
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1answer
46 views

Electrons in an Inductor

What basically happens to the electrons, does the magnetic field produced by the electron moving in the inductor affect itself. what are the forces involved? Please elucidate the mathematics. The ...
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1answer
18 views

What is the flux $\Phi$ enclosed by cyclotron orbit, which can express the quantization rule?

Suppose an electron (mass $m$, charge $e$) in the xy-plane with $B=(0,0,B)$ (The classical EOM result in circular orbit). Using the Bohr-Sommerfeld quantization rule we can find that $E_n = (n+1/2)\...
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How do we observe an electron? [duplicate]

When an electron is observed it acts like a particle and its wave function collapse. This statement is very famous in quantum mechanics, but what is meant by observing an electron? Which devices are ...
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3's a crowd. Particle me but may i have this dance? [closed]

In a particle accelerator (built for 3 particles), could we smash them into a vacuum with only enough space for 2 particles?(electrons, protons, neutrons) what would be the result?