Electrons Definition and 998 Threads

The work function of a metal is typically several eV. When we transmit electricity through cables of some 10-100kV, how come the electrons not having enough energy to escape from the metal?

My understanding is that an elementary particle A becomes entangled when it interacts with another particle B, sharing symmetrical properties with particle B, until particle A interacts with another particle C, whereupon particle A becomes entangled with particle C. When an electron gets fired...

The first result to this question in Google gives this: "An electron in an atom spreads out according to its energy. The states with more energy are more spread out. All electron states overlap with the nucleus, so the concept of an electron "falling into" or "entering" the nucleus does not...

In the 2-slit experiment using electrons, what speed do they travel at?

a. This is easy with ## q = n*e ## ## 3.2 * 10^{-9} = n * 1.6*10^{-19} ## ## n = 2*10^{10} ## electrons b. Total Lead atoms are ## \frac {8 * 6.022*10^{23}} {207} = 2.3 *10^{22} ## I used the Avogadro number. Total electrons = ## 2.3 * 10^{22} * 82 = 1.88 * 10^{20} ##, here i multiplied with...

Since the crystal spacing is given to be 0.4 nm, so d = 0.4 nm = 4e-10 m in Bragg's law formula For θ = 90° & n = 1, I got λ = 2d = 8e-10 m Using this value in De-broglie wavelength, I got p = h/λ = 8.28e-25 Now kinetic energy of the electrons is given by E = p^2/2m Using value of p, I am...

In the prompt 4c in this problem set: https://ocw.mit.edu/courses/physics/8-04-quantum-physics-i-spring-2013/assignments/MIT8_04S13_ps1.pdf. We are asked to find out how d, D and w will change (where d is the slit width, D is the distance from the slits to the screen and w is the distance...

In the known universe, the number of electrons seems to be greater than that of positrons since electrons are within every atom around us. However, when a gamma ray approaches a nucleus, a pair consisting of an electron and a positron, can be created from pure energy. If all matters are created...

For the given problem, I know that the quantized energy for the particles in a 1D box is given by - E(n) = n^2 h^2/ (8mL^2) Here m = mass of electron L = Length of the box = a Now, since there are 8 electrons, but only 2 can occupy one energy level, so I used n^2 = (1)^2 + (2)^2 = 1 + 4 = 5...

I'm having trouble to understand why it's said that electrons in the conductor band are free while electrons in the valence band are not. I know by the Schrodinger equations that the trajectory of an electron inside a specific band and with a specific energy level is a probability. From what I...

If you measure the location of an electron in helium, does it impact the expectation value for the location of the other? Also, can this experiment be conducted in practice? Thanks.

Electric currents and the things within are generally explained through the help of intuitive water current examples, where potential difference is explained through the pressure difference and electric current is explained as the flow of water. But I like to think in terms of some driving force...

I don't know how to approach this problem.

I have specific questions, but let's first give context. Initially we have an electron with momentum ##p=(E, \vec p)## and spin state ##u_r (\vec p)## and a photon with momentum ##k=(\omega, \vec k)## and polarization state ##\epsilon_s (\vec k)##. Finally we have ##p'=(E', \vec p')##, ##u_r'...

These articles have energy but do they have mass?

Hello guys, i get a little bit confused about the fact ,that static electrons produces E-Fields and after they moves one speaks only about the magnetic field .But what happens with the E-field in a moving ensemble of electrons?I mean,the E-field should also exists .It doesn't...

Hi! Situation: quasi-free electron in a 2D lattice, considering atomic potential V(r) = exp{-|r|/b} (r is the distance from the atom) I'm trying to compute the first five energy gaps at point (10), firstly I don't understand the meaning of calculated 5 energy gaps at one point and usually we...

I've found I to be .167 using the potential and resistance. I also found the volume by multiplying the cross-sectional area by the length (?) and then dividing the # of conducting electrons into that to find packing density (n). To find drift speed, I would also need the area of the block as...

The first ionization energy decreases between group 5 and group 6 due to the repulsion between the electrons in the p orbital. Although I understand that the effective nuclear charge increases between group 1 and group 2 elements, why isn't this the case between group 1 and group 2 elements...

Hi! I have read a calculation about a white dwarf star assuming the electrons are both ultra-relativistic and degenerate. My questions is - how come the ultra-relativistic assumption doesn't contradict the "degeneracy" assumption. Degenerate means the electrons are filling out all the lowest...

Sometimes I hear particle physicists refer to left/right chiral electrons as different particles that are 'mixed' by the mass term. Maybe I misunderstood entirely, but if there is even a handwavy sense in which this is the case, clarifications would be appreciated. In high energy collisions...

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...

I've been looking int Large Electron-Positron collider at CERN (an experiment which ended in the year 2000), groups of electron and positrons were accelerated along a circular tunnel so that they collided. Electromagnets were used to keep the particles moving in a circle. could someone tell me...

Hi guys I saw that equation of the velocity of electrons In a periodic potential $$ v = (1/h) grad E(k) $$ in my textbook we use in our solid state physics course without any proof or any thing and when I searched for it I found that its derived in Ashcroft book appendix E : Is there is any...

I have attached the pages in Kittel's book (pages 417-420) regarding my question. My question is simply based off of the second to last photo, where e_f = 5*10^4 K and e_1 = 1K. e_2<e_f and |e_2|<e_1. So how can (e_1/e_f)^2 be less than 1? The energy of the free flowing electron is assumed to...

Are there good references for delayed eraser experiments with electrons rather than photons?

As the temperature given was 0K, I calculated the ground state energy of the system. I considered 2 electrons to be in the n=1 state, 2 in the n=2 state and 1 in the n=3 state by Pauli's exclusion principle. By this configuration, I got the total energy of the system in the ground state to be...

I am needing clarification for a concept. I understand that electrons carry a negative charge and that protons carry a positive charge. I also understand that a plastic rod picks up electrons when I rub it with a piece of wool. From the conservation of charge, the piece of wool must have a...

Consider the light sensor in a modern camera. Light can give energy to electrons and populate the numerous "boxes" of our light sensor with extra electrons. Those boxes will temporally store the electrons till they are counted. I would like to understand this process with my "Bohmian" glasses...

For the first part, since this is a intrisinc semiconductor, n=p= intrisinc carrier concentration. Hence free electrons and hole = ##(1.5*10^{10})## per cubic centimeter. As for part 2, here are my steps. But I'm not sure if it's correct. I first find the number of atoms of one cubic...

This is my attempt but they said my answer is wrong

This isn't a specific question, but more a case of trying to mitigate any potential confusion which might arise in the future. When drawing out curly arrows for mechanisms, and the like, I'm used to thinking about which electrons "belong" to certain atoms (in a book-keeping sense) in order to...

I've been reading about semiconductor laser-driven particle accelerators over the years, and think they would make an interesting future-tech privacy screen...possibly. My design is along the lines illustrated by the diagram, but I'm wondering what actual effect accelerated electrons would have...

hi, I have read that the process of repulsion between two similar charges, such as two electrons, is mediated by the exchange of a photon. This photon somehow merges with the nearby electron and somehow directs the electron to move in the opposite direction. Is this correct? I don't quite...

Ok, so I've been on a kick trying to really understand why QM and GR are incompatible. I think I get that GR can't be realistically converted into a quantum field because it creates some infinite series that you can't use the normal tricks you would for other QM fields. Hard block, ok got it...

In ground state electron does not emit photon.Can we use QED to explain why in ground state electron does not emit any photons?

Hello, I am trying to learn Quantum mechanics and have some questions I cannot answer. cooper pairs, composite boson particles (spin number = 0 or 1) from two coupled electrons. The movement of cooper pairs is forming a superconducting current. Superconducting current does not have a...

Hi, My understanding of quantum physics is very basic. I have read that each electron has its own magnetic field; in other words, each electron acts like a mini bar magnet. I was reading about Lenz's law and an unrelated point started confusing me. I was reading this text about Lenz's law...

Homework Statement: Verify the claim of Section 7.2 that the electrons of a metal collide with the surface at a rate of about 10^30 per second per square centimeter. Do this by estimating the collision frequency of electrons in a 1.00-cm cube of copper metal with one face of the cube surface...

According to QED photons can be absorbed or emitted by electrons, and this process results in em forces via virtual photons. What determines the emitted photon frequency, and are they fully absorbed by electrons assuming photons are discrete and must be in quantized packets? How fast are...

Most gauge transformations in the standard model are easy to see are measurement invariant. Coordinate transformations, SU(3) quark colours, U(1) phase rotations for charged particles all result in no measurable changes. But how does this work for SU(2) rotations in electroweak theory, where...

Homework Statement: Two small spheres spaced 20.0 cm apart have equal charge. How many excess electrons must be present on each sphere if the magnitude of the force of repulsion between them is 3.33×10^−21N? Homework Equations: Charge of an electron e=-1.6X10^-19 C F=kq/(r^2) For this I set...

Summary: Is there anyway to calculate average distance of electrons? I know that we use wave function for orbital to show the probability of finding but my question is there any way to calculate distance between orbitals or energy states?

Do electrons have motion or they just accelerate when they get enough energy?

Publication News article It looks increasingly like something is wrong with the older electron-based results. The story of "with electrons you measure one thing, with muons another" doesn't work any more. Is that a good thing (there might be some conclusion what the radius is in the next years)...

Hi, I'm a bit confused about Bloch functions. This is what, I think, I understood: can someone please tell me what's wrong? From Bloch's theorem we know that the wave-function of an electron inside a periodical lattice can be written as ##ψ_k(r)=u_k(r)e^{ik⋅r}##. We hope that far from a lattice...

Electrons are indistinguishable, but we may pretend that they are distinguishable if their wave functions do not overlap in space. For example, an electron "a" in Chicago and an electron "b" in Seattle would produce a zero integral in [5.20], and so their indistinguishablilty would not produce...

Mainly I want to know the following thing: electrons when excited they tend to want to go back to ground state, right? One way is by photons, but how does that work? Accelerating charges creates EM waves, but in this case there was no acceleration, right? Or is the term accelerating only a way...

Hi, I am aware that the reason why objects have color is an old subject. However I come across two claims which sound like they are in contrast to each other. On one hand I read that the photons with specific frequency in incoming light are absorbed (i.e. have enough energy to move an electron...

I'm conducting a research about making a electron gun. I first tried to detect electron using nuclear emulsion plate. But I couldn't purchase one near my town. So, instead, I'm thinking about using a x-ray film to detect electron. But I'm not sure it'll work. SO, IS IT POSSIBLE TO DETECT...