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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Fractional electric charges

Since the Oil droplet experiment we are talking about elementary electric charges: Charge quantization is the principle that the charge of any object is an integer multiple of the elementary charge....
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What binds electrons to a negatively charged material?

This is probably a very stupid question but I couldn't find an answer on google. Consider a neutral material - say, some block of metal. There is exactly as many electrons as protons and the ...
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Why do electrons have rest energy?

E=mc² so inserting the value of m and c we get 0.511 MeV for electron but then what does this energy account for coz according to me electrons are not made up of any particles so this doesn't account ...
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When current flow though a straight wire does it create a magnetic dipole?

When current flow through a wire, this generates a magnetic field around the wire, this field tends to circle around the wire and called electromagnetic field. When current flow though a straight ...
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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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In a photovoltaic effect, when the electron absorbes the photon, is the electron's energy displaced?

I'm a super amateur wannabe physicist, and I'm trying to learn the fundamental workings of the photovoltaic effect. I haven't been able to understand "how" or "what" is displaced/transmitted in the ...
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How is the electron $g$-factor determined?

I found a description of the experiments at CERN where a Penning trap is used to to determine the g-factor but I could not find the value of the radius of the circle of precession, nor could I (surely ...
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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 ...
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How fast does an electron move?

I've been reading this website: www.physics.wayne.edu/~apetrov/PHY2140/Lecture8.pdf to learn how fast an electron moves in a circuit. On page #8, #9 and #10 It says to take the Cross-sectional Area ...
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What is the physical meaning of a molecular fragment having two appearance energies?

Appearance energies are particularly import when it comes down to mass spectrometers that use electron impact bombardment. They typically denote the quantum energy value for fragmenting the molecule ...
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Can classic charge radius formula be used to calculate the radius of muons or taus?

The classic charge radius formula $r$ is used commonly to calculate the radius of electrons(assuming they are spherical). My problem is: can the same formula be used to calculate radii of muons or ...
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How to create a vacuum tube & produce electron beam

I know that when an anode & cathode are placed inside a vacuum tube, electrons are emitted from cathode and goes towards anode. So, How to produce such a high voltage?, How to create such a ...
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What differences would be observed in the Stern-Gerlach experiment when using neutral fluorine (Z=9) and neutral sodium (N=11)

I have been working through some past exam papers for my Quantum Mechanics module, and one of the questions is what would be different about observing the results of the Stern-Gerlach experiment when ...
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Interaction between electrons in which the magnetic dipole moments interact more strongly than their electric fields

Asking a question Has anyone tried to incorporate the electrons magnetic dipole moment into the atomic orbital theory?, I was curious whether anyone has attempted to relate the intrinsic property of ...
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From where do electrons gain kinetic energy through a circuit?

Supposing an ideal wire, How do electrons accelerate and gain kinetic energy? What I understand: When a circuit is opened ,electrons are crowded at the negative term of the battery and have high ...
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Is Einstein's Photoelectric effect a reversible phenomenon?

If one emits a light beam in a given frequency (obviously there is a threshold frequency) over a metal plate, even on low energies, some electrons could be ejected and one could been measuring an ...
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Electron to electron interaction

I am interested to know if it would be possible to calculate the magnetic attraction between two electrons at zero space between their magnetic poles against electrostatic repulsion between them in ...
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Gaining or Losing Too Many Electrons

So I understand that an atom can gain or lose electrons and still retain it's identity - for example a Carbon atom is still carbon even if it loses 5 of it's 6 electrons because it is the number of ...
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How do electrons know which path to take in a circuit?

The current is maximum through those segments of a circuit that offer the least resistance. But how do electrons know beforehand that which path will resist their drift the least?
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Are the electrons' orbitals the same for all atoms?

Are the electronic orbitals of an atom always quantified in the same way (i.e. the same energy required to reach the next level), or does each atom have its own values for each level? If the ...
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Relation Between Current and velocity of electrons

In a conductor, all the electrons are few to move to conduction bands. If we say that magnitude Current is increased (I= dq/dt) can we infer that the velocity with which the electrons flow also ...
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Why is charge of the electron negative?

How did scientists figure out that the charge of the electron was indeed negative? I know how the cathode ray tube experiment works, but how did Thompson know that the plate that the cathode ray beam ...
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1answer
108 views

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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Multi electron interference in double slit experiment

Electrons have negative charge, and therefore repel each other. That should mean that their position, and momentum probabilities should get skewed away when in the presence of some other electron. I.e....
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How does an electron beam condenser work?

For example, a scanning electron microscope has multiple condensers that "focus" the beam into a smaller spot size. How does a condenser actually change the direction of electron flow in a non-uniform ...
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Photon-Electron interaction (Compton and Photoelectric effect)

(Some context : I am a first year engineering student and i have conceptual doubts in Compton and photoelectric effect. I have read a book "Concepts of modern physics"-Arthur Beiser and talked to my ...
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What is actually being removed when a metal conductor is grounded?

I found this image earlier this morning, and yes, there are a lot of diagrams/illustrations about this, transferring charges by induction has been introduced since the very beginning of high school ...
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Working out the radial arc of a magnetic field to get mass of electron

We have an experimental setup as below, the magnetic field strength, Bq/30s, and distances (magnet distance, Geiger counter height, Geiger to magnet centre distance) have all been recorded. The energy ...
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Stacking batteries and electron flow

About Fuel Cells and Batteries: I understand the analogue with increased water height as two cells (battery or fuel) are connected in series. However if we for instance have two batteries contected in ...
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Does an electron emit radiation the instant it absorbs it?

I was reading on the electromagnetic spectrum when I thought if an atom/electron is absorbing the energy from the light ray falling on it, how and by when will it get rid of the excess energy to ...
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From where does the radiation come from in an inverse-Bremsstrahlung process?

I'm trying to know more about Bremsstrahlung and inverse-Bremsstrahlung processes. If you know any good references that treat theses topics with a good mathematical and physical basis, please let me ...
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Why is order of electron orbital filling not completely sequential? [duplicate]

Orbitals fill in the following order, 1s, 2s, 2p, 3s, 3p, 4s, 3d, 4p, 5s, 4d, 5p, 6s, etc. Its a nice pattern that many elements follow, but there are exceptions to. For example: V: 1s2 ... 4s2 ...
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Trying to understand electron diffraction

I'm trying to understand how electron diffraction works, but I'm not really getting it. Here's an image Here are a couple of questions about it that I can't figure out. Why is the angle of the beam ...
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Has anyone tried to incorporate the electrons magnetic dipole moment into the atomic orbital theory?

The Pauli exclusion principle is related to the electrons spin. The quantum numbers are complete only with the spin quantum number. I am curious whether anyone has attempted to relate the intrinsic ...
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Charge on an electrical conductor

Consider we have very precise equipment (s) needed for this question. There's a finitely big uncharged conducting sphere. Suppose we had an extra electron from an external source and we plan to keep ...
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How do electrons keep moving when bare copper wires are rolled? [closed]

How do electrons keep moving when bare copper wires are rolled? When someone strips the wires and coils the copper, does that not affect the communication between the devices, that is, the bits do ...
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The effect of gravitational & Coulomb forces on free electrons in a conductor

In a metal, why don’t the free electrons fall to the bottom of the metal due to gravity? Also, charges in a conductor are supposed to reside on the surface so why don’t the free electrons all go to ...
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Analogy What is the difference between AC light and DC light or is there such a thing? [closed]

Is there a constant non changing static light? See analogy Analogy As AC is for alternating current DC is for direct current AC for sine Waves/Movement/Varies to light DC for + or - straight line/...
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Does electron affinity decrease with charging?

Lets consider two materials A having higher electron affinity than B while both are not too far off. If they are both insulators and A accumulate charges due to triboelectric effect. Than after a ...
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What is the exact mechanism of flow of electricity?

When a steady current flows through a conductor, the electrons in it move with a certain average ‘drift speed’. One can calculate this drift speed of electrons for a typical copper wire carrying a ...
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Why doesn’t the focussing anode diverge the electron beam again?

Consider this diagram of a focusing anode in a CRT: Question: Why does the electron beam not diverge again when it enters the focussing anode (or accelerating anode) while leaving the pre-...
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Why is lightning going from the Earth to the clouds while the electrons are going from the clouds to the Earth?

The lightning is often a discharge in advance. The (negative) charge slide occasionally a little further on in the conductive channel, wherein said channel is highlighted each time something. The ...
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Why are 2 gamma photons created? [duplicate]

When a positron and an electron come together they annihilate and produce 2 gamma photons $$e^+ +e^- \rightarrow 2\gamma$$ I can understand that they must be produced in pairs to conserve momentum. ...
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Is the magnetic dipole of the electron an intrinsic property?

The profound answer to the question How permanent magnets work? starts with Sub-atomic particles such as electrons, protons, and neutrons (and many others) have a fundamental quantity called a spin ...
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Are Cooper pairs (of electrons) entangled?

I have read this question: Does a normal torch emit entangled photons? where Quantum Journalist says: Although all the particles of a BEC are in a single quantum state, they are not ...
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In a circuit, do surface charges get influenced by external electric fields? [duplicate]

Hello ,This image represents surface charges in a circuit caused by the battery's electric field, if you were to place an other electric field source of the same magnitude (but not connecting it to ...
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Calculating force on electron

How do we calculate force on electron, knowing that it behaves both as particle and wave.
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How does a particle's energy determine interaction behavior?

I have been trying to get my head around Electron-Beam Lithography and have a small issue with what has been said in the linked YT video. At 11:35 Chris Mack says that The more energy the ...
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How does a heated object lose thermal energy in a perfect vacuum?

Suppose I heat up an arbitrary object to an arbitrary temp and then place it in a near perfect vacuum (let’s assume inter-galactic space). If there is essentially nothing for the object to transfer ...
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Electrons direction in cathode ray tube

This image below show the movement of an electron in a magnetic field, it's taken from the video [Histoire des sciences] La découverte de l'électron explaining the experience of J.J. Thompson when he ...