Electron Definition and 999 Threads

The Dirac equation for an electron in the presence of an electromagnetic 4-potential ##A_\mu##, where ##\hbar=c=1##, is given by $$\gamma^\mu\big(i\partial_\mu-eA_\mu\big)\psi-m_e\psi=0.\tag{1}$$ I assume the Weyl basis so that $$\psi=\begin{pmatrix}\psi_L\\\psi_R\end{pmatrix}\hbox{ and...

Hi folks, My understanding of the Compton Effect is that maximum energy transfer to the electron takes place when the photon scattering angle is 180 degrees. For the following please reference Evans "The Atomic Nucleus" ...

When I see explanations for quantum tunneling, the discussion is around the probability of an electron manifesting itself before the potential barrier, and after the potential barrier. However, looking at the curves draw, there is a non-zero probability (the evanescent part of the wave) inside...

I came across a problem that seemed fairly interesting; it asks what would be the trajectory of an electron released from rest inside a Faraday cage (which is itself within a uniform gravitational field ##\vec{g} = -g\hat{y}##). I didn't quite understand their explanation. They say that...

Neutrinos oscillate at different flavors while propagating in space and this is due to their mass.Any particle being massless cannot oscillate between different flavors while leptons with the mass of the electron and above are very unlikely to change their flavor. Will we able to detect a change...

Is it possible for an electron in the 1s orbital of an hydrogen atom to be indefinitely far from the nucleus in a given instant? From the Schrodinger equation we can see that the radial probability is NEVER zero, so it would be possible to see an electron in the moon, for example. But if I...

Hello! I read in several (more accessible) papers (e.g. https://www.sciencedirect.com/science/article/pii/S1049250X0860110X) that the EDM of the electron is so small, because one needs to go to 4 loops or higher to get a non-zero effect. It seems like at 1 and 2 loops there are some symmetry...

I've got a quick question on the relationship between the kinetic energy of individual electrons and the total electrical energy they create. I have a radioisotope - a beta emitter - which produces electrons with around 1 MeV (1.60218×10-13 Joules / 4.45049×10-17 Watt-hours) of energy. I keep...

In the book" The Quantum Theory of Radiation", Heitler derived the transverse self-energy of the electron(Chapter III, Section18, Eq.(23)) $$\frac{{{e^2}}}{{\pi m}}\int_{\text{0}}^\infty {kdk} $$ which is the energy of the electron under the action of the vacuum fluctuation of the radiation...

Modern batteries use double-sided anode and cathodes for greater energy density. Series wiring of batteries is typically accomplished by connecting the anode of one cell to the cathode of another. However, can series be accomplished by stacking double-sided anode and cathode alternatingly with...

It will try to produce a neutral atom but it depends on the amount of energy that electron is shot at the atom, if it is great enough energy for ionization it will produce cation, If it is not enough for ionization it will make a neutral atom or anion, I think.

I think that an electron adds up in the valance shell of an atom because an atom tends to achieve the nearest noble gas configuration. But I don't understand how and why electron enters the valance shell. Energy is released when an electron adds up in the valance shell. But why is energy...

Hi, I've been reading out of curiosity about linear accelerators to get a general ideal of the principles behind them. My main concern is that, as far as I could tell, there are two different types (I'm sure there are more than two, but I want to keep things simple) of Linear Accelerators...

Hello, this problem is causing headaches, it would be very helpful if you could tell me if you know of a book where you can solve it. Maybe my English is lousy because I use a translator. Thank you very much.

hello Witch of these are certain sentences? a-\dfrac{e}{m_e}>\dfrac{H^{-}}{m_{H^{-}}}\cdot{1000} b-\dfrac{e}{m_e}>\dfrac{H^{+}}{m_{H^{+}}}\cdot{1000} The first accurate measurement of e/m was made by english physicist J.J. Thomson in 1897, who demostrated that the quotient charge-mass of the...

Let's suppose a solar electron moving directly towards Earth's equator at a high speed. This electron meets Earth's magnetic field, which points to the north, at a distance ten times the Earth's radius, where magnetic field is almost uniform. Which will be the direction this electron describes...

I've written out the half reaction 8e- + 9H+ + SO42- = HS- + 4H2O and I know the logK = 4.25 (that's the constant mentioned in the prompt) I've written out the equilibrium statement of 10^4.25 = ([x^1/8]*[H2O^1/2])/([10x^1/8]*[e-]*[(10^-8.2)^9/8] However, from there, it seems like I have two...

So I'm reading up on this device and what I get is that in all electron guns once the electrons are emitted they would tend to repel one another so in order to make the beam focused instead of spread out across, one uses magnetic fields in the electron microscope, So after the focused beam hits...

On p. 246 in the Peskin QFT textbook, below is stated where Z3 is defined as the residue of the q2 = 0 pole, explicitly as $$Z_3=\frac{1}{1-\Pi(0)}$$ and e is the bare charge. In advance, the exact photon two point function is calculated as $$\frac{-ig_{\mu\nu}}{q^2(1-\Pi(q^2))}$$ Though...

I honestly just have no idea where to start on parts c and b. I tried 1.1*10^-12 N x 3218 m for part a, which was right. But I'm lost on b and c. I'm also wondering if we have to include a gamma factor in any of this, but I'm unsure how or where. Any help would be amazing.

Does the negative terminal of a battery have a negative charge due to having a surplus of electrons? If so, then why do the surplus electrons from the negative terminal of the battery not discharge to the human body or Earth (which have a neutral charge) when touched?...thereby causing the...

Does anyone know theory about how the perturbation lines are for 1s hydrogen electron? By perturbation I mean the perturbation that is caused by moving an electron so that the E-field lines it emits becomes dragged. by perturbation I mean for example dragging a charge as described below Above...

Do they mean something like this?

I am really stuck on what to do here in this question I have arrived at forming an equation to work out the radius of electron orbit from doing the following However I do not know what to do next as I don't know what the value of n (quantum number) must be? :oldconfused: Any help would be...

I know that current chose the way with the lowest resistance but this is becouse that few electrons will go on the two path and the smallest number of electron .,Is the path that the current go throw . But how does a single elelctrons "choose" is path . And also if I connect two wire to a...

Hello all! I wrote a reaction mechanism for a sequence that forms an ester. Here is a link to my work: <Link deleted. See attachment.> <Moderator's note: please upload all material to PF instead of using external servers.> Do you agree with my answer? Thanks for your help!

Have tried doing this question but I'm a bit confused on where I'm going wrong This is what I have done but get a value that doesn't match to any of the options given above? Any help would be really appreciated, Thanks!

I know this is a rather weird question but I'm in high school studying physics and chemistry and a lot of the content is pretty basic for what I aim to learn. One topic that I was curious about was electron spins and how that works, because correct me if I'm wrong but aren't they waves of energy...

Following a thread on building a cloud chamber I searched some other sites and encountered some eg. diagrams of electron tracks which puzzled me. I searched for actual photos and found some very irregular tracks ascribed to electrons, but nothing like these. I can't see how they could arise...

For example, we have this two potencial wells approaching, the electron is confined in one. the final appearance will be like this: THEN, if we know a wave packet is formed by many frequencies, but in a potencial well there are just few frequencies allowed, energy levels, so let's say, one...

traditional definition of electron affinity: the amount of energy released by an element in its gas form when gaining an electron second definition?: the stability gained by an element in its gas form when gaining an electron (e.g. halogens are more stable after gaining an electron, and when...

Homework Statement:: 1. Does the increase in kinetic energy in (for example) water that results from increasing its temperature result from electron excitation (i.e. increasing electron energy levels) or simply increasing their velocity or vibration amplitude/frequency? 2. If excitation is...

Maybe because when you don't observe it, the Schrödinger equation predicts the totality of interactions (paths) of the electron over an infinite time, all the paths it can take ( forming a wave like function ) which is actually all the paths the electron can take overlapped... and when u...

Just wanted to check in my workings to see if they are correct (seemed to be too short to me?) Since electrical conductivity is 820 (ohm.m) which is = n*e*(mobility) Mobility =0.17083? And I can simply get drift velocity by multiplying mobility with an electric field (600V/m)? Cheers

Hi every one, In Compton effect I understand that the electron is considered free electron because the energy of the incident photon is very much larger than the binding energy of the atomic electron. But iam not sure why the electron is considered to be at rest (v=0). please help. Thanks.

Hello! Assume that I have a parallel plate capacitor. If i place an electron close to the negative plate, it will move in a straight line (and accelerate) towards the positive plate. Now, assume that I place a neutral dielectric close to the electron trajectory (parallel to it), say at 1 mm away...

A radiation-shielded go-pro camera was sent through an electron beam irradiator. You can see the effects that the radiation has on the camera in the video. I wonder how many rads it was exposed to.

Quick question: let's say we have an atomic electron in the ground state which requires, say, one "unit" of energy* to jump up to the next orbital energy state. If a photon arrives with a bit more or less than this, say 1.00003 or 0.99997 units of energy, is there some finite, non-zero...

Hi all, I'm right now confused about this. As far as I know, when changing from a level to another, the change in l (subshell) can only be a difference of 1, and ##m_{l}## can be the same or a difference of 1. In this case, since the question wants me to state possible quantum states of...

Hi there, popping by here to check my answer because another online platform has already answered it but my answer appears to be wrong. I can't seem to understand why though :/ Since I can find the energy at a state to be ##E_{n}=\dfrac {-13.6z^{2}}{n^{2}}eV## At ground state where n=1...

This is the equation given. I attempted to use Radial Equation, obtained from separating variables, to solve for ##E_1##.

Conservation of Energy: 9GeV + E = 5.3GeV + 5.3GeV Therefore E = 1.6GeV for the threshold energy. How would I find the velocity of B0 mesons so that I can calculate their mean distance? Then it would just be distance = velocity of b0 * mean proper lifetime Right?

Nitrogen has an atomic number of 7. Thus, A nitrogen atom has 7 electrons. Nitrogen’s electron configuration is: [He] 2s2 2p3 The nitrogen element has five valence electrons present in 2s and 2p orbitals. So it would have five dots placed around the symbol for nitrogen. Is this correct? I need...

q = 1.602e-19C mass_electron = 1.098e27 c = 3e8 Omega(Mag_flux_den) = 5GHz Lorentz factor = 100 synchrotron radiation at frequency v = 5GHz Mag_flux_den = (Omega(Mag_flux_den) * c * Mass_electron * Lorentz factor) / mass_electron Mag_flux_den = (5000 x 3e8 x 1.098e27 x 100 ) / 1.602e-19 =...

how high does a vacuum need to be for electron gun to work? for example, will 1 pascal work, will 1 tenth of a pascal work? is there a minimum vacuum for a electron gun to work?

Homework Statement:: The total energy of the electron in a hydrogen atom is normally −13.6 eV. Which one statement below, based on this fact, is correct? 1. The work required to completely remove the electron from the atom is 13.6 eV. 2. The electron is in a circular orbit with a kinetic energy...

Hi, These questions may seem basic, yet, I do not have an answer for that. The density of electrons and the density of holes in an intrinsic semiconductor are equal at equilibrium. From this, it seems that holes are simply lack of electrons that are given enough (thermal) energy to escape...

a) since the eletric field is perpendicular to the inicial velocity, the x component is constant, hence Vf.cos45=Vo. This gives Vf=0,6√2.C b) Ei=γi.Eo , γi=5/4 , Ef=γf.Eo , γf=5/(2√7) Finally, Ei+e.E.d=Ef. Apparently this is incorrect, why??

Homework Statement:: Consider an electron trapped in a one-dimensional finite well of width L. What is the minimum possible kinetic energy of the electron? A) 0 B) Between 0 and h^2/8mL^2 C) ≈h^2/8mL^2, but it is not possible to find the exact value because of the uncertainty principle D)...

I am watching this video; at the 8:20 mark it shows that a proton in a magnetic field will align with the magnetic field very easily if there is no shielding from electrons, and therefore will require energy to shift to the opposite spin state; makes sense to me. I also understand that when...