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.
In this thread Ifqm has asked what was the Lagrangian of an electron and a proton interacting together. He proposed a Lagrangian containing electron-proton interaction and the tiny QED field correction (electromagnetic tensor part). His first Lagrangian seems intuitive as a sum of 2 Dirac...
In the questions solution, they conceptually discuss how the DOS for the conduction band becomes larger when ##m_c## is larger than ##m_v##. This then implies that there is "more phase space for electrons than holes", which confuses me. How can you make a statement about the phase space of...
A common explanation for the origin of (some) color is that a material absorbs a, say, red photon and an electron moves from one energy level to a higher energy level, the difference in energy being the energy of the red photon. The material then appears bluish having absorbed the red light...
The answer from answer key is electrons in gas absorb photon energy and causes electron to move to higher energy level. When electrons de-excite, photons emitted in all directions so dark lines occur.
My question is if photons are emitted in all directions when electrons move from higher to...
In studying the Aharonov-Bohm effect, a model of an electron confined in a box is used, for example, on page 353 of Modern Quantum Mechanics by Sakurai et al. The box makes one turn along a closed loop surrounding a magnetic flux line.
In the derivation, there will be an integration involving...
I am interested to simulate a problem in mcnp6, in which gamma rays (energy let say 10 Mev) incident on a aluminum disk and produce electron spectrum which further move in a gas (e.g co2)cell to produce chernkove radiation. Here gamma produce electron and electron further produce chernekov, in...
Imagine an electric field between two charged plates that is so intense that its energy density is enough to produce real electron-positron pairs.
These electron-positron pairs annihilate to produce photons that radiate away.
Does the electric field between the charged plates regenerate so...
This pop up on anyone radar? Electron mass different throughout the universe?
I don't see how this section could have passed peer review:
The masses of electrons, muons, and tau can be explained by the different curvatures of universe, galaxy, and solar system, respectively.
I've seen crazy...
Now we have a particle-antiparticle asymmetry problem.
But, if we define electron and neutrino as antiparticle, will there be a problem?
Original formula
Modified formula
Original formula
Modified formula
If the classification of electron and neutrino is changed to antiparticles, the...
Is the drift velocity of gas' free electrons during the gas discharge higher than the one of the conductor's electron fliquid while the voltages supplied to these two substances are the same?
I know the field I don't know whether the field will be uniform inside the cavity or not. If it is, I don't understand how or why the electron will move. I got the force(considering uniform field inside the cavity) as epr/3E0. But then again I don't understand how the electron will move. If I...
Does anyone know how to calculate the coefficients for higher order (sixth and beyond) terms for the electron anomalous magnetic moment? I have a clear understanding of calculating the Schwinger term, but beyond that I cannot find anything in the usual QFT textbooks. The usual papers often...
Hi. I am a high school science teacher (A&P, Chem, and Environ Bio & Eco) so my understanding is limited on subatomic particles...please forgive me if this is a really stupid idea.
I teach my chem students about electrons, orbitals, electrons' "address" using the four quantum numbers, 1s2 -1/2...
TL;DR Summary: Find the possible outcomes of ]##L^2## and ##L_{z}## and their respective probabilities of an electron of an idrogen athom with function:
##\psi(r) = ze^{-\alpha r}##
Hi guys, I have a problem with this exercise.
The electron of a hydrogen atom is found with direct spin along...
If you think of electrons with spin as bar magnets, you know bar magnets of opposite polarity when put next to each other in any respective rotation don't cancel each other's magnetic field out. So what's a more apt analogy for electron paired have no magnetic field?
Influencing electrons angular momentum
You can use magnetic fields to influence the intrinsic value of angular momentum (spin). When an electron interacts with a magnetic field it experiences a force known as torque – twisting force in the direction of the magnetic field. Therefore, if you pass...
I'm asking mainly about part (c). Within the context of BBN, I'm a little unsure how you account for different baryons (i.e. does ##n_b## include neutrons, protons, hydrogen and helium, given that helium itself contains both neutrons and protons?)
For completeness, for part (b) I would just use...
According to STR: E=MC^2.
When an electron and proton are independent( without influence of any kind of fields, especially electrostatic fields )their rest masses are Me and Mp. When they combine to form Hydrogen atoms they emit photons. So, some energy loss in the form of photons. So, now...
Flash memory depends on tunneling in order to work—electrons have to tunnel through an oxide layer. Now, the wavelength of an electron is at most 24 pm. An atom is on the order of 100 nm wide, and the oxide layer must be at least several atoms thick. How can there be any significant tunneling?
Let's take the example of an electron in of a hydrogen atom . It continuously interact with the proton of the hydrogen atom . Both the proton and electron are continuous interacting with each other. It is said that wave function collapse when it is being observed or observers interact with it...
I have been doing some reading on electron reconstruction from proton-proton collisions at CERN. In some of the papers I have read, plots such as the one In the figure are included. What I would like to know is why they have chosen to plot the x and y axes as cos(phi) * tan(theta) and sin(phi) *...
Kuusela https://research.utu.fi/converis/portal/detail/Publication/32053938?lang=en_GB (published in AJP) (PDF here) describes a pseudothermal light source that can be built easily in college labs, and can be used to do some quantum correlation experiments. They propose this as an alternative...
Can we describe / explain the B x v force in the electron's own reference frame without reference to relativistic invariants, 4-vectors, tensors et al?
The aim would be to explain things like the following video without the notion of "field lines" that electrons and wires move through. But the...
Homework Statement: Real world application of freshman physics
Relevant Equations: TBD
This is not a homework question, this is relevant to my work. It seems simple enough (introductory) but I keep running into problems.
An electron is emitted from an surface (material is irrelevant, could...
Showing the motion is simple harmonic seems routine. The 5th equation on p. 674 gives ##E=frac{1}{4\pi\epsilon_0}frac{qx}{(a^2)+(x^2)}^frac{3}{2}##, but matching expressions for ##\omega=k/m## yields only ##x=frac{ea^2}{2}##. Something in the model is escaping me. Thanks for any help offered!
Quarks and electrons have clear electric polarity.
So, can we assume that an electric source as electromagnetic is needed to create those kinds of particles?
hi, while studying Majorana mass term can be added for the neutrino - as they are neutral - but cannot be added for the electron -as it would violate the charge conservation - i could not understand how charge conservation for Majorana mass term of electron is violated.
kindly help
Hello everyone,
I have the problem above. I chose to put ##F_G = F_Z## to solve it and end up with a radius ##r = 1.04\cdot 10^{-7}##m.
Solutions on the internet choose to put the gravitational force equal to the centrifugal force and obviously end up with a completely different solution. I...
The peak of the radial probability density for the 1s state is at the Bohr radius ##a_0##. But if we consider equal volumes as cartesian boxes, can one fairly say the electron has a higher probability of occupying a box near the nucleus than elsewhere because the peak of ##\psi^* \psi## is at zero?
I've known for a long time that the muon mass is approximately 3∕2×137 times that of the electron, as in Nambu's empirical mass formula from 1952. I recently wondered what the difference was as a multiple of the electron mass, using current CODATA figures for the muon to electron mass ratio and...
An electron requires an "exact" wavelength photon to transition from one level of an atom to another. Yet the wavelength of a photon has a a continuous probability distribution, implying that the point probability of achieving an exact wavelength is zero. One can only talk meaningfully about...
I've been looking at a practice test for an introductory class in quantum physics, and I've found a really weird question. It asks for an estimation of the force that an electron exerts on the walls of a box of known length during a collision.
This seems like an entirely nonsense thing to ask...
ik this is basic knowledge, that all groups go up in reactivity the further down you go in the group, except for group 7, where this is reversed.
however i don't understand why, because in group 7, the electron shielding still increases the further down the group you go, like with all the other...
I know that the Heisenberg Uncertainty principle states that the position of an electron is uncertain, however, if an electron is created due to beta decay, then at what location is it more likely to begin its movement?
Is it right inside the proton? Is it the outer edge of the proton? Is it...
Hello! I want to get the electrostatic interaction (between and electron and a nucleus), while accounting for the fact that the electron can also be inside the nucleus (e.g. in an S##_{1/2}## state). I ended up with this double integral...
I am doing the Millikan Oil Drop experiment to determine the charge of a single electron. I have been following the lab manual provided by the manufacturer, https://hepweb.ucsd.edu/2dl/pasco/Millikans%20Oil%20Drop%20Manual%20(AP-8210).pdf.
The manual defines a simple method to calculate for...
I have read, what I believe, misleading articles about generating entangled electron pairs. Some suggesting the electron is split. But this isn't possible because it's an elementary particle with charge/mass and Spin properties. So how do we achieve generating entangled electrons with opposite...
I just want to elaborate the wave nature of electron from davisson and germer experiment . there is resonance of energy (54 ev)provide to electron for which it show wave like behavior's.
give some better explanation for this.
How do you know which binding energy shell to use? In the solution it uses K and L2. Why specifically L2 and not L3 or L1 for example?
And what should I do with the information to omit electrons lower than 20kev? I initially thought that meant to omit the electron binding energies lower than...
This is SAMPLE PROBLEM 25-7 from "Physics" by Resnik, Halliday, and Krane, in the chapter "Electric Field and Coulomb's Law".
After describing the behavior of uniformly charged spherical shells:
follows a sample problem:
The solution to (a) goes to say that the volume inside R/2 is 1/8 of the...
According to Leonard Susskind, i.e. the electron has periodically interactions with the Higgs field condensate, that change the electron alternately to be right-handed an left-handed. At 44:20 in the video he says, that, according to the Dirac theory, the mass of the electron is proportional to...
TL;DR Summary: Find acceleration of electron in dB/dt >0
Hello. Here is a problem that i'm not so sure about:
Inside a solenoid there is a time-dipendent magnetic field B, so we have dB/dt = b (constant).
We want to know the acceleration of an electron:
a) placed in the center of the solenoid...
The problem of bound states of an electron trapped in a dipole field is being studied by Alhaidari and company. (See, for example, https://arxiv.org/ftp/arxiv/papers/0707/0707.3510.pdf). It is not clear to me why the point dipole approximation is used everywhere in such calculations. Can't an...
Hello! If I have a (diatomic for simplicity) molecule containing a nucleus that decays by electron capture, are there any theoretical calculations of how that would behave in practice? For example would the lifetime change? Would the resulting molecule still be bound? For example if I start with...