Electron Definition and 999 Threads

  1. T

    B Can Hydrogen Atoms on Earth and the Moon Share Electrons?

    Is it possible to find a hydrogen atom which atomic nucleus is on Earth and electron is on moon?
  2. SovietComics

    B What is the speed of electron movement in atoms at different temperatures?

    I am just asking how fast an electron spins around the nucleus of the atom at lower temperature such as indoors? and at high temp such as explosion or fire? I know that electricity electrons and energy transfer are much quicker, but I am just asking how fast an electron goes around the nucleus...
  3. N

    Relativistic motion of an electron in a uniform electric field

    dv/dt is the acceleration, so I thought I could find the acceleration from F = qE = ma = dp/dt. But this is a relativistic case, so the proper acceleration is a = F/mγ3, where v in the gamma is the v of the electron and F = eE. However, I'm not sure if this is correct, because the constant τ...
  4. entropy1

    I Can we accurately determine the trajectory of an electron using a SG detector?

    Would this be an accurate portrayal of measuring the spin of an electron with a SG detector?: The electron is in a superposition of spin-up and spin-down; Upon entering the magnetic field of the SG detector, the electron enters a superposition of an upward trajectory and a downward trajectory...
  5. P

    A Half filling? Free electron gas? 2D tight binding lattice?

    It is well known that the 2D free electron gas fermi momentum can be expressed as follows, k_F=\left(2\pi n\right)^{1/2} where n is the electron surface density. Assuming this 2D electron system can be considered as 2-D tight-binding square lattice whose eigenergy can be written as...
  6. F

    I Why does the energy level of an electron in an atom have a width?

    Electron in atom at higher level(excited state) of energy has tendency jump to lower level of energy.Then the state of electron is unstale,so there is uncertainty in energy of the electron(the level of energy has a width).What cause the level being a band of energy but not a thin line of...
  7. P

    Many Worlds and the Measurement of an Electron

    Summary: How does many worlds deal with the measurement of an electron's position in space? Hi all - I am reading Sean Carroll's book on quantum mechanics and reached the end of the section on "branching and splitting" without getting an answer. I will lay out my assumptions and then get to...
  8. M

    Moving electron under two magnetic fields

    In this question, I would have to calculate the force in respect to time. However, the question gives me the value of the mass of the electron. In my attempt, I didn't take that into account. I just replaced ##v## with ##\frac{d}{t}## and made the Lorentz force undergone by the particle...
  9. M

    Electron with circular trajectory in a magnetic field

    I'm not sure how I'm able to calculate the velocity of the particle using the formula without knowing the force exerted on it. Also, I don't understand why the question also provides the mass of the electron.
  10. Drone0

    Electron in a triangular quantum well with triangular barrier

    Hi, it's been so long since I learned quantum mechanics. So the only thing I can solve now is the square quantum well problem. But I need help because I have to solve this problem of quantum well. I tried some calculation but not far.I try to draw the capacitance-voltage profile by drawing the...
  11. I

    B What happens during electron capture physically?

    I wonder if someone could explain what is known about electron capture in which a proton captures an electron which then becomes a neutron? I have read that a proton which has two up quarks and a single down quark will have the the creation and destruction of multiple quark - antiquark pairs...
  12. I

    What Does U_200 Represent in the Nearly Free Electron Model?

    This is a multi-part problem. I'm having trouble getting started. Any insights would be greatly appreciated. Prompt: To start off with, I think I'm finding the notation confusing. Specifically I'm not sure what U_200 refers to. Some thoughts: I know that both the potential, and the periodic...
  13. Frigus

    How can O- and COO- act as an electron releasing group in a π system?

    can anyone explain me how O negative and COO negative acts as electron releasing group,I understood how alkyl groups acts as electron releasing group but I can't understand this
  14. allisonpw

    A Exploring Electron Triplet States for Physics Questions

    How did you find PF?: internet question about electron triplet states I'm a retired accelerator physicist entertaining myself by trying to understand physics questions like entanglement better. I calculate the expectation value of the product of two electron spins in the singlet state with...
  15. F

    How do we know the mass of an electron?

    I've been researching the proof of subatomic particles given the fact that we have never seen them before. It has always been recognized that protons, electrons, and neutrons exist; but I question how we know for certain they exist. Across my studying I've realized that in 1897, J. J. Thompson...
  16. jisbon

    Finding the displacement of an electron between 2 charged rods

    Since electron will stop eventually due to efield, equation is : ##v^2 = u^2 +2as## Where v = 0 , u = ##1.04*10^8 m/s## ##a = \frac{qe}{m} =\frac{(1.6*10^{-19})(e)}{9.11*10^{-31}}## ##e = \frac{Q}{4\pi\epsilon(1)}+\frac{Q}{4\pi\epsilon(4-1)}## Are the equations correct? Or is my concepts wrong?
  17. D

    B Is the Velocity of Electron Spin Calculable Using Classical Models?

    Addressing to electron as being rigid body that precesse is probably controversial. Are there any attempts to stick to that model and to calculate its quantize tangent velocity?
  18. D

    I Ionization -- Efficiently ionizing every electron off of atoms

    Is there a radiation method for efficienctly ionizing every electron off of atoms to produce strictly protons and neutrons Without generating tremendous heat?
  19. S

    Can Electrons Carry Infinite Energy?

    Are electrons limited to how much energy they can carry(if that term can be used)?
  20. C

    Details of the electron cloud in a magnetron: density and size?

    In a standard kitchen-microwave magnetron, like all magnetrons, a cloud of electrons forms which whizzes around and generates GHz electric currents in an outer ring electrode. For such a standard kitchen appliance, 800W made with ferrite magnets, what is the typical volume and density of the...
  21. dRic2

    I Are electron bands symmetric in the reciprocal space?

    Hi, in the lecture notes my professor gave us, it is stated that, due to Kramers theorem, the energy in a band must satisfy this condition: $$E(-k) = E(k)$$ But, judging from actual pictures of band structures I don't find this condition to be true. Here's a (random) picture I guess it looks...
  22. Z

    A Effective mass of the electron for Si

    https://ecee.colorado.edu/~bart/book/effmass.htm#short Looks like the effective mass for holes in Si can either be 0.57 or 0.81, according to the link above. Is there a temperature regime where one effective mass should be used instead of the other? Is anyone able to explain in layman's terms...
  23. I

    I Bohr model for electron energy states

    I know that we use quantum mechanic and wave function to calculate probability of finding electrons but is there anything valid about bohr model that we still use it?
  24. F

    How far should an electron be fired so it stops before reaching the plate?

    I am trying to solve the following problem: My attempt at the problem: $$m = 9.11 * 10^{-31}kg$$ $$q = 1.6 * 10^{-19} C$$ $$V_0 = \sqrt{\frac{2KE}{m}} = \sqrt{\frac{2 * 1.6 * 10^{-17}}{1.6 * 10^{-19}}} = 5,926,739 m/s$$ $$F_{net} = -F_{e} = ma$$ $$a = \frac{-F_{e}}{m} = ma$$ $$E =...
  25. jisbon

    Electron traveling between charged plates

    So I can understand how to find out velocity of electron moving between these 2 plates, by using: How am I supposed to find the 'minimum' velocity though?
  26. dRic2

    I Periodic electron motion in a perfect conductor using a semiclassical model

    According to the semiclassical approximation, in response to a constant electric field I would get a periodic motion of the electron, like this: The sinusoidal type function is the velocity, while the function that goes to infinity is the effective mass. Thus I was wondering, since ##v## also...
  27. E

    A Future of the electron neutrino mass limits

    In five years also experiment KATRIN will give either the upper bound of electron neutrino mass (0,2 eV) or even the mass of the electron neutrino. https://www.katrin.kit.edu/ My question is, what we can expect from the astronomical and non-astronomical measurements to improve these data? I...
  28. R

    B Energy Band Diagram: K.E. & P.E. of Electron in Semiconductor

    Hi, Can anyone explain the concept of K.E. and P.E. in a semiconductor? Why Ec (lower level of Conduction Band) is considered as P.E. ? and why the Difference between the higher energy state and Ec is Kinetic energy ? I understand it if I look at the Bohr model but I am not clear how to look at...
  29. H

    I Is an atomic electron transition a phase transition?

    Is atomic electron transition a phase transition? https://en.m.wikipedia.org/wiki/Atomic_electron_transition
  30. GuillemVS

    I How to choose the way an excited electron loses energy?

    When electrons get excited they are unstable, therefore they want to go back to ground state. One way they do so is by creating photons (e.g. mirrors), but I've also read that they can create electricity (another electron?). Photoelectric is how it's called, right? If so, how can we choose...
  31. H

    I Spherical Symmetry & Electron Spin: An Exploration

    Can an electron in a spherically symmetrical potential energy function have non-zero spin angular momentum?
  32. H

    I Why does an electron orbital have a preferred z axis?

    Why is there a preferred z axis even though the potential energy function is perfectly spherical? Shouldn't the electron be around the nucleus in a spherically symmetrical way?
  33. A. Neumaier

    A Born's rule for the QED electron violates causality

    Summary: Born's rule for the QED electron violates causality. [Since the thread where some of this material was presented was closed for further discussion, I summarize here the main content relevant for the above topic.] The free QED electron can be described in terms of a non-local...
  34. epotratz

    I Voltage between electron and proton in ground state hydrogen atom?

    I’m not sure if this belongs in classic or quantum physics... but here it is...Is it possible to calculate the “voltage” between an electron and a proton in a ground state hydrogen atom?I know the ionization energy is 13.6 eV, so I assume it's safe to say the voltage is 13.6 volts at a certain...
  35. B

    Electron helix in a magnetic field

    I thought that a nearly parallel entry path would result in a helix of very small, but constant, radius. I would not expect the electrons to focus at a point, but continue along the infinite helix. What have I missed?
  36. K

    Detect Single Electron: Fuji-Film & Kodak-Film?

    When I want to detect single electron(double-slits experiment), can I use usual photosensitive film(like Fuji-film, Kodak-film)? And, what specification I need?
  37. AuntyMatter

    I Spot Electron: Unveiling the Wave-Function Collapse

    You have probably heard this a thousand times before, but here goes... We have an electron gun pointing at a double slit setup. We switch it on and emit a single electron. The electron approaches the double slit. At each instant that electron has a definite position. We do not consciously know...
  38. Jamister

    A Electron Vertex Function in QED

    In Peskin book they calculate the QED Vertex Function named Gamma which depend on two scalar functions called form factors F1(q^2), F2(q^2). they are calculating F1(q^2) and they do not really finish calculating for what I understand. They are just showing the Infrared divergent is canceled by...
  39. D

    I Trying to understand electron orbitals

    I'm having trouble understanding this process. The electron is absorbing the photon and has a changed orbital corresponding exactly to the photons energy. During the absorption the electron "jumps" energy levels, Is this process instantaneous? What are the equations that describe dynamics of...
  40. Mayan Fung

    I Why is a pair of an electron and a positron unstable?

    We know that an electron and a positron will annihilate and emit gamma ray. But the electron and positron possesses initial kinetic energy meaning that it is difficult for them to really collide in each other. Just like Earth is not dropping into the Sun even with the gravitational pull. So I am...
  41. P

    I Atomic Electron Jump Wavelengths

    what is the shortest wavelength of light that an atom can radiate by electrons jumping shells, and longest wave length
  42. e2m2a

    Center of mass momentum of a photon and electron system

    Suppose there is a photon with momtum p=h/lambda moving in the positive x-direction. Suppose it collides with an electron at rest and is completely absorbed by the electron, and that after the collision, the electron moves to the right with the same momentum of the photon. This seems...
  43. M

    A Double copies and the black hole electron

    Because they evaporate, quantum micro black holes resemble unstable elementary particles: you can create them by smashing stable particles together, and then they will decay back into particles, as if it was all just another scattering process. Certainly in string theory, elementary particles...
  44. patric44

    The volume of the nucleus to the volume of the electron

    i'am trying to find the ratio between the volume of the nucleus for the hydrogen atom to its electron , but when i try to use the previous equations it seems wrong as i'am getting a low number like if the electron is bigger . i used the the classical electron radius as it was the only thing that...
  45. Error404!

    A Effective Mass of Electron for White Tin

    For some work of mine i need the plasma resonance frequency for tin nanoparticle, i searched various research papers and found different efffective masses tin for different orbits. here i attached screen shot from W A Roger and S B Woods (Cyclotron effective masses in white tin). What value is...
  46. Z

    Eigenstates of a free electron in a uniform magnetic field

    I started with the first of the relevant equations, replacing the p with the operator -iħ∇ and expanding the squared term to yield: H = (-ħ^2 / 2m)∇^2 + (iqħ/m)A·∇ + (q^2 / 2m)A^2 + qV But since A = (1/2)B x r (iqħ/m)A·∇ = (iqħ / 2m)(r x ∇)·B = -(q / 2m)L·B = -(qB_0 / 2m)L_z and A^2 =...
  47. B

    A Are there phonons in a free electron gas?

    It is well-known that the electron gas of volume V has an equation of state p=p(V) and thus has a bulk modulus $$B=-V(dp/dV)$$. Suppose the electron gas had no underlying lattice but was confined. Do phonons emit and absorb in such an electron gas at finite temperature? The reason I ask is...
  48. Eugene567

    What forces are acting on electron in a circuit?

    What forces are acting on electron in a circuit? What is the source of such kind of forces? Do electrons act on each other in electric current? If i have an ordinary electric circuit with only one resistor, then if i raise resistance, the electric current goes down. As I understand it happens...
  49. fluidistic

    A Does electron energy contribute to current

    It is often said that in metals only the electrons having an energy within ##k_BT## of ##E_F## can contribute to a current. I do not understand where this ##k_BT## comes from. I know it enters the conductivity tensor because such a tensor can be written in terms of a surface integral over the...
  50. D

    Why doesn't an electron influence itself in Maxwells theory?

    Hello everyone, for quite some time I am struggling with the following question: If we consider the action for a single particle in Classical Electrodynamics $$S[x(\tau),A(x)]=\int - m\ ds - \int d^4x\ A_{\mu}(x)j^{\mu}(x) -\frac{1}{4}\int d^4x F^{\mu\nu}(x)F_{\mu\nu}(x) $$ with $$ds=...
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