Electron Definition and 999 Threads

Homework Statement Calculate the wavelength of an electron which has 5eV of energy.Homework Equations de Broglie's equation: lambda=h/p , kinetic energy equation: K=0.5mv^2 The Attempt at a Solution My attempt: I figured out that using de Broglie's wavelength equation was necessary for this...

In the CODATA table of physical constants, there are very precise numbers given for mass of electron and mass of proton. And an even more precise number for proton electron mass ratio. But when you divide the mass of proton by the mass of electron, you don't get the same number as the proton...

For example, a cosmic electron projectile at 1TeV, is it possible to fly through a nucleus just like a bullet drills through a cake and makes the cake insensible recoil? After drill-trough, the electron may have some deviation from incident direction because the route may not exactly pass the...

Homework Statement To what velocity would an electron (neutron) have to be slowed down, if its wavelength is to be I meter? Are matter waves of macroscopic dimensions a real possibility? 2. Homework Equations I have assumed this could apply to pretty much any free particle of mass m, and is...

If you raise the electron to other higher shell states, can light transmission throug -h a SOLID BLACK opaque object. Modified the original question because it was unclear. I won't repeat the same question over, and over, but what I have said in previous questions may get repeated in the...

Okay guys Felt a need to post this since it's been confusing me for a long time Say,for example,we have an atom with its electron occupying the 3s orbital Now let's say we energise the atom and constantly supply it energy that the electron which receives the energy(or a part of it)gets excited...

I was studying for (first year) physics class and was playing around with the Bohr Model of Hydrogen. I tried calculating the electric potential at the Bohr radius r =5.29e-11 m, where V = \frac{e}{4 \pi \epsilon_0 r} (from the point-charge formula for electric potential) and I got 27.19 J/C...

I was reading an interview of Dr Subir Sachdev in the latest online issue of Quanta Magazine, and he mentions that Cooper pair electrons in the high temp superconductors (HTSC's) are globally entangled with one another, but in the low temperature (type 1) superconductors, they are not, and I...

How do you go about calculating electron densities, especially when impurities are involved?

Hello PF members, In Newtonian perspective, applying a force to a object like ball causes it starts to moving and getting more speed and more energy. Do photon apply a force to the electron when it interacts with the atom and electron absorbs it? It seems electron gets more energy and goes to...

I know fel operate a wide range of wavelengths, but does anyone know the main operating wavelength for the US navy's 1MW fel?

Homework Statement Consider an electron with spin ##\vec{S}## and magnetic moment ##\vec{\mu}=-\frac{e}{m}\vec{S}##. It is moving with the velocity ##\vec{v}(t)## relative to the inertial frame of reference ##I## through the electric field ##\vec{E}##. Calculate the angular momentum the...

Homework Statement 2 parallel plates of length 4.0 cm are arranged horizontally in a vacuum. The upper plate is positively charged and the lower plate is negatively charged. An electron is projected horizontally with an initial velocity of 6.0 x 106 ms-1 and experiences a constant electric...

Hi all, I'm new to the forum so I hope this is the right place to pose this question. I've managed to find answers to nearly all of the questions I've had regarding certain aspects of physics on the forums, but haven't seen this addressed anywhere. According to Wikipedia (...

Homework Statement A conduction electron moves through a block of Cu until it reaches the surface. At the surface the electron feels a strong force exerted by the nonuniform charge distribution in that region. This force tends to attract the electron back into the metal which is what causes the...

I am trying to understand selection rules in atomic transitions. So, one of the selection rules says that only transitions where orbital quantum number is changed by 1 are possible. If that is the case how can hydrogen in ground state get to 2s state? Can we detect spectroscopic line that...

Hello everyone, What happens if an isotope that normally decays through EC has no electrons at all? For example how does 7Be4+ decay?

The book I'm reading is discussing the physics of semiconductors. I'm having a hard time understanding a passage in section introducing n-type semiconductors. (Phosphorus is used as the impurity) The book says: "At normal operating temperatures, this extra electron breaks its bond with the...

Homework Statement The motion of an electron is given by x(t)=pt^3 +qt^2 +r, with p = -1.9 m/s^3 , q = +1.3 m/s^2 , and r = +9.0 m. What is the velocity at: a) t=0s b) t=1s c) t=2s d t=3s Homework Equations v=x/t The Attempt at a Solution I have tried plugging in the time to equal to t, in...

I would like to calculate the electron kinetic energy ejected from a cathode as a function of the electric field and pressure without known of the temperature and velocity.

A high intensity continuous wave laser passes through an electron cloud. Please discuss what would happen and in relative amounts. Thanks

Hi, I am a newby so please excuse my ignorance. With reference to the single electron double slit experiment, one thing has been bugging me. The videos that illustrate the particle or wave behaviour do not tell us how the single fired electrons are directed to either the left or right slit...

Dear PF Forum, I think I have asked too many question for one day. I'm trying to understand antioxidant and free radicals. But, first I'd like to understand oxidation number. The oxidation number for hydrogen is +1 or -1. I can understand that. Either Hydrogen must lost one electron or gains one...

Since the binding energy of an electron in outer shell is smaller than the binding energy of the electron in inner shell, why the photon kick out the electron orbiting in inner shell? It is always easier to kick out the electron with less binding energy, is it not?

During Internal conversion, the nucleus transfer some energy to an electron in K-shell cause the electron eject out of the atom. After which there left a hole in K-shell then either by releases auger electron or characteristic X-ray the atom de-excited itself. During Electron capture, a proton...

Are axis of rotation and revolution of an electron revolving a nucleus parallel? if axis of rotation and revolution of Earth can be not parallel to each other then why not for electron? We add or subtract (s) = 1/2 (value of spin quantum number) to orbital quantum number (l) to get total angular...

Why is the electronegativity of fluorine higher than chlorine but not electron affinity? How is it possible that it has a stronger attraction towards a bonding pair of electrons than when a new electron is added to the atom?

Hello Lastly I was thinking a lot about electron density definition. It is not intuitive for me and I'm looking for any mathematical tool that could explain it to me more. My friend told me about idea to derivate it from propability density function using Dirac delta distribution. I'd like to...

Dear PF Forum, I'm interested in the future. How mankind will benefit from fusion power. But there are some terms that I don't understand. Electron Volt. https://en.wikipedia.org/wiki/Electronvolt Volt https://en.wikipedia.org/wiki/Volt Perhaps this yes/no question will confirm my confusion...

I cannot find a website that answers this question, and all diagrams I see do not show that ATP is used. Does this mean that these processes are intrinsically spontaneous? I can see how the electron transport chain is spontaneous, as the oxidation of oxygen to water is favorable (E 1/2=0.7V).

I get the notion that an elementary particle derives from a localized perturbation of that particles quantum field. What I don't get is how that perturbation can lead to two alternative quantum states for that particle - for example, an electron with two spin states (spin up and spin down). Are...

Hi I'd like to ask you about interpretation of electron density definition. According to the "Handbook of Molecular Physics and Quantum Chemistry" it goes like: ##\rho (\textbf{r})=N \sum_{\sigma_1}^{\sigma_N} \idotsint_{\mathbb{R^3}} |\psi_V (\textbf{r}_1, \sigma_1;\dots...

I have heard that Feynman and Wheeler briefly discussed the idea of the 'one electron universe'. According to Wikipedia it came up as follows: It wasn't really a serious idea, more a 'thought experiment'. But what interests me is the fact that electrons are literally indistinguishable. Not...

We were digging through some of the apparatus today and amongst a few dual beam tubes we found this, pictured below It's very similar looking to a dual beam tube shape-wise but as you can see the internal structure is quite different. What is this? After looking at it for a while we suspect...

Homework Statement Electron on n=6 level emits wavelength of 410.2nm. What energy level does it move too? Homework Equations 1/L = R ( 1/N^2 - 1/n^2) where N is initial and n final R=1.096779*10^7 m The Attempt at a Solution 1/410.2 = 10967790 (1/36 - 1/n^2) 1/4498975152 = (1/36 - 1/n^2)...

I was reading the book "Electricity and Magnetism" 3rd edition (Purcell, Morin) and under section 1.3 the book says (I quote): "What holds the electron together is as mysterious as what fixes the precise value of its charge. Something more than electrical forces must be involved, for the...

Homework Statement What is the internal energy of an electron moving at 0.750c0 in the Earth reference frame? Homework EquationsThe Attempt at a Solution E = mc^2 E = (9.11 * 10^-31)(.750)(3*10^8) However, this appears incorrect. What have I done wrong or what am i missing?

Homework Statement What is the escape speed for an electron initially at rest on the surface of a sphere with a radius of 1.0 cm and a uniformly distributed charge of ##1.6\times 10^{-15}##? That is, what initial speed must the electron have in order to reach an infinite distance from the...

Homework Statement A charge Q = -820 nC is uniformly distributed on a ring of 2.4 m radius. A point charge q = +530 nC is fixed at the center of the ring. Points A and B are located on the axis of the ring, as shown in the figure. What is the minimum work that an external force must do to...

Is there a way in determining the distance between an electron and a positron as they anhilliate? If this figure has been determined already, what is it? Thank you very much for your help!

Electrons have both mass and electromagnetic charge, so why is it that an electron's rest energy is equal to its mass energy with E=mc^2? Shouldn't it have some energy left over to excite the electromagnetic field? The mass energy excites the Higgs field, so why is there no energy for the EM field?

Do electrons excite the EM field or do they just create virtual photons that do? If you could only see EMF excitations, would you see the electrons or virtual photons coming from the electrons?

While 2nd law of thermodynamics emphasizes past->future time direction, CPT theorem says that at least microscopic physics has some symmetry between past and future. For example the Feynman-Stueckelberg interpretation suggests to see anti-particles as traveling back in time. So thermodynamics is...

Hi, I have a couple of questions on photoelectrons. When a photoelectron of about 3-eV (varies) interacts within 0.2-um depletion region of silicon, what happens? I know, it will generate an electron-hole pair with an efficiency of 1 for 3.6-eV photoelectron. But what happens if the...

Imagine a semiconductor lattice - a regular lattice (e.g. of Si or Ga) with a small fractions of a different atoms (like Mn). The natural question is: how electrons flow through it? It can be measured experimentally: put a potential and use scanning tunneling microscope to map electron flow from...

Hello, I've been reading the Stern-Gerlach experiment, and where the concept of electron spin is introduced, am facing a problem, i.e., if you consider electron a charged rotating sphere, then the electromagnetic energy and size of the electron becomes huge! So how do you deal with this? Thanks...

I was watching a video about the double slit experiment because I found it interesting, However, watching this vid raised more questions than it did answer. I would like to know why did the outcomes of the experiment only change when we observed it... wasn't the electron interacting with...

Hello PF members, Source of the gravitational field in the Einstein field equations is energy–momentum tensor and the curvature of space-time is directly related to the energy and momentum of whatever matter and radiation are present. Suppose a electron at rest . 1- Can this electron be...

Hello, I would like to thank all of the contributors on this site. You have helped me in more ways than I can count. I am struggling with the following concept and was wondering if anyone could clarify this. As the electron gets further away from the nucleus, its energy increases. This makes...

There's a rule bout unlike charges attract and like charges repel one another. How is it that in chemical bonding like in covalent bonding electrons form a bond or there is attraction from one unto the other. Isn't that ironic?