The electron is a subatomic particle, symbol e− or β−, whose electric charge is negative one elementary charge. Electrons belong to the first generation of the lepton particle family, and are generally thought to be elementary particles because they have no known components or substructure. The electron has a mass that is approximately 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum (spin) of a half-integer value, expressed in units of the reduced Planck constant, ħ. Being fermions, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: they can collide with other particles and can be diffracted like light. The wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavelength for a given energy.
Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism, chemistry and thermal conductivity, and they also participate in gravitational, electromagnetic and weak interactions. Since an electron has charge, it has a surrounding electric field, and if that electron is moving relative to an observer, said observer will observe it to generate a magnetic field. Electromagnetic fields produced from other sources will affect the motion of an electron according to the Lorentz force law. Electrons radiate or absorb energy in the form of photons when they are accelerated. Laboratory instruments are capable of trapping individual electrons as well as electron plasma by the use of electromagnetic fields. Special telescopes can detect electron plasma in outer space. Electrons are involved in many applications such as tribology or frictional charging, electrolysis, electrochemistry, battery technologies, electronics, welding, cathode ray tubes, photoelectricity, photovoltaic solar panels, electron microscopes, radiation therapy, lasers, gaseous ionization detectors and particle accelerators.
Interactions involving electrons with other subatomic particles are of interest in fields such as chemistry and nuclear physics. The Coulomb force interaction between the positive protons within atomic nuclei and the negative electrons without, allows the composition of the two known as atoms. Ionization or differences in the proportions of negative electrons versus positive nuclei changes the binding energy of an atomic system. The exchange or sharing of the electrons between two or more atoms is the main cause of chemical bonding. In 1838, British natural philosopher Richard Laming first hypothesized the concept of an indivisible quantity of electric charge to explain the chemical properties of atoms. Irish physicist George Johnstone Stoney named this charge 'electron' in 1891, and J. J. Thomson and his team of British physicists identified it as a particle in 1897 during the cathode ray tube experiment. Electrons can also participate in nuclear reactions, such as nucleosynthesis in stars, where they are known as beta particles. Electrons can be created through beta decay of radioactive isotopes and in high-energy collisions, for instance when cosmic rays enter the atmosphere. The antiparticle of the electron is called the positron; it is identical to the electron except that it carries electrical charge of the opposite sign. When an electron collides with a positron, both particles can be annihilated, producing gamma ray photons.
Hi I am doing an electron gun diffraction right now and I wonder why the angle below is 2 phi.
What I think about it that it's actually the results of two waves one is shown below and the other is a wave
with the same accident angle but negative "those two rays will be symmetric around the...
How can I see, by looking at a band structure if the substance in question can be viewed as a free electron gas (FEG) or not?
What characterizes a FEG in a bandstructure plot?
Thanks in advance!
Homework Statement
A photon with an initial wavelength of 0.1120 nm collides with a free electron that is initially at rest. After the collision the wavelength is 0.1140 nm .
a) What is the kinetic energy of the electron after the collision?
b) What is its speed?
c) If the electron is...
I have some questions about forces acting between electrons (-1 charge) and up quarks (+2/3 charge).
I did attempt to make sure its a valid line of questioning by privately asking mfb...
& I'll ask all the questions up front so as not to annoy the moderators with my follow up questions.
So...
General question to members, when you look at the results and the interference pattern of the double slit experiment for electrons. Does anyone have information on what the empty space is on the screen. The electrons fixed location on the screen shows gaps always. I watched one persons theory...
My concern is an electron tube.
From what I understood so far, gas molecules will have an average velocity derived from the Maxwell distribution, and that velocity will influence in the electron collision frequency.
I can't see clearly though how the electron velocity itself in the presence...
I'm trying to understand electron spin. I understand that if you try to explain the intrinsic angular momentum of an electron, you end up with the surface spinning several times the speed of light.
However, calculations always seem to be done classically. Shouldn't it be done relatavistically...
Dear Sirs,
After my theoretical post on vacuum diode electron flow, I decided to try and measure it physically. I didn't have a vacuum tube, so I improvised with some tungsten wire, aluminum sheets and some screws and the result was usable. Obviously the tungsten wire fails after some time due...
Saha-Boltzmann equation describes the ratio of number densities between any two consecutive ionization states and its product with the number electron density i.e.
$$n_e\frac{n_{i+1}}{n_{i}}$$
Here, ##n_e## is the electron number density, ##n_{i+1}## is the number density in ##i+1## ionization...
Dear Sirs
I have been going through the "radiotron designers handbook", but I can't seem to find the answer to the doubt I have about the electron flow of the source Vp. Kindly consider the below two circuits, the difference is the polarity of Vf.
Question: In both circuits, the electrons...
Dear Sirs,
Maybe this is general knowledge, but I couldn't find the answer where I looked, so please bear with me.
Consider a circuit consisting of a mechanical generator (some spinning magnets and coils) and a wire across the generators output. At some point the wire gets hot and starts a...
How does the electrons interact in QFT? if they are not localized? For example, when one electron repels another or does an atom repel another atom? How do electrons find each other for interaction?
Hello there!
I'm trying to check the first order (1 loop) correction to the electron magnetic moment. I'm following Schwartz and Peskin, but both of them have a point where they hide the calculations, and I'm not sure if my calculations are correct.
The point is exactly this:
I don't know...
Homework Statement
In the problem, an election is moving though 2 charged plates
vertical electric field amount is given and its perpendicular to the electron’s original horizontal velocity. The initial speed of the electron is given and the horizontal distance it travels is given. Then it...
My understanding of the QFT model of a free electron is that there is a localized higher energy level in the electron matter field which couples to the EM field in two ways: (1) the coupling allows the electron matter field to 'feel' a force from an outside EM field and accelerate in response...
Homework Statement
Using free electron model find the number of electron quantum states per unit volume in ##[\varepsilon_F, \varepsilon_F + \Delta \varepsilon]## energy interval of sodium. Fermi energy of sodium is ##\varepsilon_F = 3.22 eV##, and energy band width is ##\Delta...
Hello there,
I'd like to model a simplified version of a "Magic Eye" tube (e.g. without the amplification triode, and for a start, 2 dimensions only), or the visible display behavior.
What I'm talking about:
https://en.wikipedia.org/wiki/Magic_eye_tube#Operation
Here is a nicer depiction of...
Homework Statement
What is the magnitude of the momentum (in kgm/s) of an electron traveling at 0.8c
Homework Equations
p = mv
The Attempt at a Solution
see photo. I said A but the answers said B.
Can anyone tell me, What quantum state really is? Is it applicable for all sub atomic particles? Then, Can anyone explain how two electron are never in same quantum state. And Does proton or neutron follows the same law as electron for obtaining unique quantum state.
If I throw the electron from electron gun with some acceleration .Will it maintain it's constant acceleration? If yes then it radiates photons from where will the electron gets energy to constantly radiate photon? If not then why?
Hello everyone. I'm having trouble understanding this example: https://ecee.colorado.edu/~bart/book/book/chapter2/ch2_5.htm#2_5_2
In this system of 20 electrons with equidistant energy levels, how is it known that there are only 24 possible configurations, and how are those configurations found?
Can we could interfere electron with photon, this question is come from logic both are waves. Is anyone did that before.?(I know that electron isn't a scalar wave)
Hi,
I've been interested in the science behind electrons/magnetism for quite a while. I've been learning quite a bit from various sources online. However there is one thing that's really nagging me.
Magnetic fields result from moving electrons. That indicates that a permanent magnet has...
Hi, I'm having trouble understanding angular moment of the one electron hydrogen atom.
Solving Schrodinger equation on a referece system (say S) I get the energy eigenstates. They depend on three quantum numbers, n, l, m
\frac{-ħ}{2 m}\nabla^{2} \Psi - \frac{e^{2}}{4 \pi \epsilon r} \Psi =...
This is an elementary question on visualizing the interaction of an electron with the surrounding EM field in QFT. I believe in QFT the electron is viewed as an excitation of the Electron matter field with an associated coupling constant between the electron field and EM field (say q) - q...
If I'm scattering electrons off of an atomic nucleus, can I infer any information about the duration of time the electron was accelerating by looking at the wavelength of the emitted bremsstrahlung radiation? I am wondering if it would be possible to derive a time interval between electron...
I am trying to find the thermal speed of electron at room temperature.
kT = (1/2)mv^2
which gives v=√((2kT)/m)
but answer says it should be √((kT)/m)
Where did that 2 go?
Hey!
Let's say we have an electron and proton colliding head-on.
We will have ##|p| \sim E##
Where ##p_1=(E_1, \vec{p_1})## &##p_2=(E_2, \vec{p_2})##
If we want the available energy. We can calculate ##\sqrt{s} = \sqrt{(p_1 + p_2)^2}##
We get $$s= p_1^2 + p_2^2 + 2p_1p_2 = m_e^2 + m_p^2 +...
Homework Statement
One way to establish which transitions are forbidden is to compute the expectation value of the electron’s position vector r using wave functions for both the initial and final states in the transition. That is, compute ∫ΨfrΨidτ where τ represents an integral over all space...
I'm reposting this thread with some editing suggested by fresh_42:
1. Homework Statement
Calculate the mass, velocity and the de Broglie wavelength of an electron and an alpha particle, given the kinetic energy K = 2MeV
Homework EquationsThe Attempt at a Solution
please find attached![/B]...
Hi,
As far as I understand spin orbit coupling is the interaction between proton of atom and electron. Proton's motion(from the frame of electron) around electron creates magnetic field. Hence electron experiences magnetic field. Does this magnetic field produces a Zeeman effect which cause...
I know that total magnetic moment of an electron (I am not sure if it is magnetic moment of electron or atom, please clarify this) is sum of magnetic moment caused by orbital motion and spin angular momentum.
So,
Total magnetic moment = Orbital magnetic moment + spin magnetic moment
Do I have...
Suppose you have a pair of electrons in the same quantum state, and are thus spin entangled, and they absorb a pair of photons and release them at the same time. How would this affect the photons? Would the photons be entangled? Would it affect the photon spin, and if so, how would it affect the...
Hi all, I am having trouble understanding the some ideas presented in some notes I've been reading, help is greatly appreciated!
I've uploaded screenshots of the material I'm referring to below, the last two images are what I'm mainly referencing, and the first few are to provide context...
Previously I posted a problem concerning Electron-neutrino scattering, but as I couldn't describe the problem clearly, so I am trying to post the problem using latex codes to present it in the correct way.
For a couple of months, I am trying to calculate the invariant amplitude of the Neutrino...
If the mass of the electron has been changing during the evolution of the universe, then the orbits of the electrons would also change, which will shift the light spectrum of each atom.
Could this explain red shift of far galaxies, and the shift is not because the universe is expanding?
Henry
For a couple of months, I am trying to calculate the invariant amplitude of the Neutrino electron scattering in the standard model (SM) approach where I am not considering any kind of approximation and using the SM propagator for W Boson and Z Boson.
I tried to do as following,
find out the...
In Abraham Pais book (which was first published in 1982), he states the following:
"Quantum field theory has taught us that particles nevertheless have structure, arising from quantum fluctuations. Recently, unified field theories have taught us that the mass of the electron is certainly not...
Homework Statement
For silicon at T=300K with donor density ND=2×109cm−3, acceptor density NA=0 and ni=8.2×109cm−3, calculate the equilibrium electron and hole concentration
Homework Equations
n_0=\frac{N_D-N_A}{2}+\sqrt{\frac{N_D-N_A}{2}^2+n_i^2}
p_o=\frac{n_i^2}{n_0}
The Attempt at a...
Homework Statement
What is the radius of the orbit of an electron traveling at 9.0 x 10^6 m/s around a zinc nucleus which contains 30 protons?
Homework Equations
I don't know if this problem can be solved quantum mechanically, all I can think of doing is solving it classically, using Coulomb's...
Is a photon fully absorbed by a electron in metal?
Ejected electron is a free electron or bonded one?
Is it possible to have a zero work function? If not why?
I want to study about this detaily ,can you prefer some reference papers?
Homework Statement
An electron in a hydrogen atom falling from an excited state to the ground state has the same wavelength than an electron moving at a speed of 7821 ms^-1. From which excited state did the electron fall from?
Homework Equations
I used the kinetic energy equation:
K = (m...