Electrons Definition and 998 Threads

Homework Statement An infinite line charge (wire) has lambda = lambda0. It produces an electric field of magnitude 5E4 N/C at a distance of 2m. Determine the typical force between two adjacent extra electrons in the wireHomework Equations E_line = lambda/(2pi*r*epsilon0) The Attempt at a...

Homework Statement A charged nonconducting rod, with a length of 1.33 m and a cross-sectional area of 3.40 cm2, lies along the positive side of an x axis with one end at the origin. The volume charge density ρ is charge per unit volume in coulombs per cubic meter. How many excess electrons...

I have studied electrical engineering, and I've seen some discussion about this question in general. However, the question that I have on potential loss of electrons in a generator circuit is a little more specific. Is the energy that is transferred/generated purely produced by the movement of...

Homework Statement Two identical 9.60-g metal spheres (small enough to be treated as particles) are hung from separate 500-mm strings attached to the same nail in a ceiling. Surplus electrons are added to each sphere, and then the spheres are brought into contact with each other and released...

Do electrons become more likely to be found in certain places as the temperature approaches 0K?

According to the quantum mechanical free electron model the average energy is E=3EF/5 for the 3D case. Nevertheless I saw in a specialised physics book that for the 1D model the average energy at T=0 is 0 and wanted to know if it is the same for the 3D case.

Hello. Let's have two electrons with same orbital quantum number li and these electrons are in antiparallel; one electron has magnetic quantum number mi = a and and other electron has mi = -a (but we don't know which one has ml = a as we're in coupled representation to talk about total angular...

Electrons are moving VERY fast. However, they don't have a high drift velocity in a circuit. Why? Is it because every time they advance a little bit they collide with an atom? Or is it because the electric field in a circuit is not strong enough so the electrons don't get pushed enough?

When it's desired to detect an electron coming through one of the slits in the mask of the double slit experiment, how exactly is the detection done without blocking the electron from reaching the background screen? In another thread it's mentioned that a semiconductor detector is placed behind...

Hi all, With the photoelectric effect is it the 'sea' of free electrons that are ejected if the photons are above threshold frequency (i.e. Conduction band electrons ) rather than valence electrons ? If say very energetic gammas are used then suppose this could knock out valence electrons but...

Homework Statement The planet Jupiter has a moon Io. Volcanic activity on Io releases clouds of electrons which travel at high speeds towards Jupiter. During a 15 s time period, 2.6 × 10^26 electrons reach Jupiter from Io. Calculate the current.Homework Equations I know current I = Q/t...

I was reading through a thread and read someone say that there is really only one electron traveling through time which is why all electrons we see are the same. IS this an accurate claim? if so, where does it come from?

I would like to ask how free electrons make metals conduct heat and electricity? Metals seem dull, their surfaces are shiny and reflect the light? So are these properties also related to free electrons? I don't know true word for dull but it might mean the light cannot go through a dull object...

I have two questions... I'm sorry for my bad English. - Is it correct to think of the Higgs Boson as a quantization of the Higgs Field, as the photon is the quanta of Electromagnetic Field? - The property we call spin appears when we analyze electrons interacting with a magnetic field. But...

Please help me with this. I am having a hard time understanding the role of displacement currents in a circus. The common knowledge is actual current is the movement of electron in a circus. Now, if there is a gap and an AC source, there would be an electric displacement field and a displacement...

the current SM states that electrons, muons and tau are all different fundamental particles. are there any theories that suggest there is only 1 fundamental charged lepton, the electron, and that muons and tau are either electrons that are in a higher energy quantum state, and therefore mass...

Homework Statement The question states that an electron and positron, each with rest mass energy of 511keV collide head on and create a proton and antiproton each with rest mass energy 938MeV. The question asks us to find the minimum kinetic energy of the electron and positron. Homework...

I watched a documentary about Quantum mechanics. There's a phenomenon which Einstien called "spooky action at a distance" states that two electrons appeared in the same event are related to each other in a spooky way,which means that if one of them has a specific state then the other one will...

Homework Statement The figure shows wire section 1 of diameter 4R and wire section 2 of diameter 2R, connected by a tapered section. The wire is copper and carries a current. Assume that the current is uniformly distributed across any cross-sectional area through the wire's width. The electric...

So, as far as I know free electrons are just electrons that have been 'released' from the shell of an atom and can now move. If this is true, what is it that causes the electron to become free in the first place? Thanks in advance to any answers ☺

Homework Statement Simple question we have to answer: (Physics) How do I release the electrons from the cathode with a color filter? (The so called Photoelectric effect)Homework Equations none The Attempt at a Solution[/B] Here we have a conflict , the so called wave-particle duality, if...

I'm trying to understand (well, maybe in an oversimplified way) what permanent changes, if any, would be experienced by a positive electrostatically charged plate used to accelerate a free electron in a vacuum, but where the electron would not strike the plate. I assume there would be some...

Photon is the force carrier for charged particles. Questions: 1. Are photons generated between proton and electron in an atom? 2. If yes who generate the photon? The proton or the electron? 3. If yes, quantum mechanically, the electron is never at a fixed position, what is the photon doing...

Homework Statement In solid state physics,we know all the states of free electrons can be expressed by the First Brillouin Zone. We know the $$E(k+K)=E(k)$$ where K is reciprocal lattice vector. We also know that the kinetic energy of the electron is $$E_{k}=\frac{\hbar^2k^2}{2m}$$. [/B]...

I understand that one way of creating quantum entangled electrons is by splitting a Cooper pair. Is then their spin property used in the measurement, as this must always sum to ##0## for a Cooper pair? If that is the case, do quantum entangled electrons only exist in the singlet state, where the...

I have a simple doubt to keep things clear. Why doesn't electrons fall into the nucleus of an atom? Is it because of the high velocity of electrons? If so, at what velocity will the electron be slow enough to collapse into the nucleus?

The problem: A simple cubic metal has an electron density such that the Fermi energy just touches the edge of the first Brillouin zone. Calculate the number of conduction electrons per atom for this condition to be fulfilled. The attempt at a solution: I know that the electron density for a...

If you have a multi-electron atom and you swap two electrons around, what happens to the wavefunction? I think nothing happens because electrons are identical, but then they can have different spins, so would the wavefunction change if you swapped a spin up electron with a spin down one?

Hi. Consider a simple circuit consisting of a voltage source ##U## and a load with resistance ##R##, e.g. a lamp or a motor. The current is given by ##I=U/R##. The number of electrons passing the circuit per second is ##n=I/e##. The power consumed by the load is calculated by $$P=U\cdot...

Homework Statement The beam of electrons in a cathode ray tube contains electrons traveling at 8.4x106 ms-1 and the current throgh the tube is 2.8 micro A. a) how many electrons are emitted per second from the cathode of the tube b) what is the number of electrons per unit length of the beam...

Basically, I'm asking about loosely-bound electrons, e.g. everyday static electricity. Can their combined wavefunction evolve to a low-energy state "at once", so that they emit a single high-frequency photon, rather than multiple photons of energies suggested by the potential difference? If...

Homework Statement In a group assignment we had to find out how many electrons were transferred to pieces of tape after we pealed them of a table. The second part of the project asked us to imagine that one piece of tape was a distributed charge and that the other was still a point charge...

Homework Statement Describe a method by which the charge / mass ratio e / m of the electron has been determined. Calculate the deflection sensitivity (deflection of spot in mm per volt potential difference) of a cathode ray tube from the following data: electrons are accelerated by a...

Homework Statement Two parallel metal sheets of length 10 cm are separated by 20 mm in a vacuum. A narrow beam of electrons enters symmetrically between them as shown. When a PD of 1000 V is applied between the plates the electron beam just misses one of the plates as it emerges. Calculate...

I'm taking a module in solid state electronics and I'm a bit confused with the energy band diagrams. I was told that the region between the top of VB and and the bottom of the CB is the "forbidden gap". However after learning about N-type semiconductors(silicon), I see that the extra electron...

Is the distribution the same as Boltzmann distribution? Have anyone made a mathematic equation for the KE of free electrons on a piece of metal?

Homework Statement Two electrons in helium have ##l_1=1## and ##l_2=3##. What are the values of ##L## and ##S##? From this, deduce the possible values of ##J## and find how many quantum states this excited state of helium can occupy. Homework EquationsThe Attempt at a Solution For ##L## the...

Homework Statement [/B] An electron e- and positron e+ annihilate to produce two photons. a_ Why are two photons produced rather than one? b_ Assume that the e- and e+ are at rest just before they annihilate. In their rest frame, what are the energies and momenta of the photons? Define the +x...

Hello, I'm a high school student interested in fusion. I've done a bit research online but I got a bit confused how does stellarator like W7-X drives electrons to run in the same direction without plasma current. I know in a tokamak, the plasma current makes electrons follow a certain direction...

Homework Statement A metal sphere with a diameter of 10 cm has a charge distribution of 1.09085 x 1018 electrons/cm2 on its surface. What is the electric field strength at a distance of 25 cm from the surface of the sphere? (Answer: 5.5 x 1012 N/C) Homework Equations I wasn't given any...

Hi! I have a question about Linear Energy Transfer for electrons. According to the definition the linear energy transfer is equal to the energy dE which a charged particle loses at a distance dl. But what does dl mean in case of electrons? Is LET calculated per unit of full path length or per...

I don't understand why electron moves this way... e.g. A light object (crampled paper) going down until gets hit by the wind will go parallel (at least a few seconds) to the wind direction ... why not with electron?

heisenbergs uncertainity says that we can never predict the position and velocity of a particle exactly simultaneously. that is we can never be sure where an electron or a proton would be seconds from now. its all about probablity. then how can these particles together form something like we...

This isn't really a homework question but I do have to know it for my lab report so I figure this is a good place to post it. So for my lab we had the setup that is displayed in the picture attachments. My question deals specifically with step #9 of the lab instructions. I'm assuming that the...

<--Why electrons move up if the Magnetic field is Horizontal? at 0:14 <-- the Magnetic field is Horizontal but the electrons are also moving horizontally...

Image source: at 02:30

This is a multiple choice question that, after one incorrect attempt, I got correct; however, I want to actually understand what the explanation means. I'm hoping someone here can help. Homework Statement Two electrons, each with mass m and charge q, are released from positions very far from...

How would you solve the Schrodinger equation for an electron in an atom. What potential do you use? Thanks!

A friend of mine posed a question; if you take a rubber ball and bombard it with electrons, what would happen? I posited that some of the electrons would likely stay on the surface of the ball, giving it a negative charge. I then suggested that if under the "right" conditions you may be able...

Homework Statement Suppose electrons enter the electric field midway between two plates at an angle θ0 to the horizontal, as shown in the figure, where L = 5.1 cm and H = 1.1 cm. The path is symmetrical, so they leave at the same angle θ0 and just barely miss the top plate. What is θ0? Ignore...