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.
As we see in this Phet simulator, this is only the real part of the wave function, the frequency decreases with the potential, so lose energy as moves away the center.
we se this real-imaginary animation in Wikipedia, wave C,D,E,F. Because with less energy, the frequency of quantum wave...
during physics, I was chatting to a friend, and the conversation reached this question ,I know it is a series of probabilities, but how do we know for certain that it an individual particle, how do we know it is not just a field of energy? (Tell me if I sound stupid)
I tried asking a similar question in cosmology but got no answer there so here goes...
Suppose I am on a windowless spacecraft in the middle of an intergalactic void. I know that the spacecraft is spinning from measuring the centrifugal forces but have no way of observing the outside...
Hello,
Context is Inverse Compton Scattering with an pulsed electron beam interacting with a pulsed laser.
A laser has a Raleigh length of Z_r = w_o^2 * pi / lambda
w_o is the the radius of the spot size, lambda is the laser frequency.
I want to match this spot size to a pulsed electron bunch...
With regards to the number of states available to the electrons in these solids.
1. a mass of polycrystalline iron (plenty of free electrons)
2. quartz (has practically no free electrons).
3. semiconductors
Which of them has the most number of states available to the electrons?
Which has...
I've been thinking about this problem for some time now and think that I need to find E to solve for σ, but I have no idea how to go about that. How do I approach this problem?
Why there is not voltage or current just for 1ms if I connect a multimeter ground to the negative terminal of a DC power supply or charged capacitor? Why electrons in measure lead and DMM device cannot sense a bulk of electrons (or lack of it)? I tried with an 5kV DC power supply too. In an...
I connected a PVC insulated alligator clip test lead to a 12V (give 20V) DC power supply positive terminal and a multimeter. After that I connected an other one to the multimeter ground, and a third one to the power supply negative terminal. I turned the multimeter to DC V measure mode.
When I...
I figured that we would simply add up the forces acting on the electron (the electric force Fe and the magnetic force Fb) and then equate this to the given acceleration multiplied by the mass of the electron like so.
vector Fe + vector Fb = (mass of electron) (vector acceleration)
since vector...
There are two kind of electron configuration as I read so far.
There are one such as spdf and other such as, for example, 2 8 8 2.
What is the name of these electron configurations?
What is the difference?
My Textbook says this is the formula to find energy values for electron shells:
$$E_{mol of electrons} = \frac{-1312kJ}{n^2}$$
where $n$ is in electron shell number
But when we divide by 1 mol to get the energy value for each electron we get
$$E_{electron} = \frac{-2.178 \cdot 10^{-18}}{n^2}...
1) I know that the binding energy is the energy that holds a nucleus together ( which equals to the mass defect E = mc2 ). But what does it mean when we are talking about binding energy of an electron ( eg. binding energy = -Z2R/n2 ? ). Some website saying that " binding energy = - ionization...
So my thought process is as follows, since the initial centripetal force and the second magnetic force are working together, we can set up an equation to calculating final frequency.
However, I am struggling with how this can be done given so little numbers.
mvi^2/r + qvB = mv^2/r
Am I on the...
A free electron, or any other quantum particle, has an uncertain position/momentum, according to Heisenberg uncertainty principle. The squared amplitude of the wavefunction determines the probability of finding the electron at any point of the space. Accordingly, atomic orbitals are attributed...
Homework Statement
Homework Equations
m2 = E2 - p2 ([/B]The Attempt at a Solution
I got stuck by not knowing how to handle the frames and I thought you can view the Z boson (CoM) frame, but then you simply get that mz = 2me
Homework Statement
An electron is at rest in an oscillating magnetic field
$$ \mathbf B = B_0 cos\left( ωt \right) \hat k $$
where ##B_0## and ##ω## are constants.
What is the minimum field (##B_0##) required to force a complete flip in ##S_x##?
Homework Equations
$$H=- γ \mathbf B \cdot...
How is neutron degeneracy pressure able to support a much higher density object such as a neutron star where electron degeneracy pressure only supports a comparatively less dense object such as a white dwarf. Conceptually I would think electron degeneracy pressure to be stronger due to the...
Hi I am doing an electron gun diffraction right now and I wonder why the angle below is 2 phi.
What I think about it that it's actually the results of two waves one is shown below and the other is a wave
with the same accident angle but negative "those two rays will be symmetric around the...
How can I see, by looking at a band structure if the substance in question can be viewed as a free electron gas (FEG) or not?
What characterizes a FEG in a bandstructure plot?
Thanks in advance!
Homework Statement
A photon with an initial wavelength of 0.1120 nm collides with a free electron that is initially at rest. After the collision the wavelength is 0.1140 nm .
a) What is the kinetic energy of the electron after the collision?
b) What is its speed?
c) If the electron is...
I have some questions about forces acting between electrons (-1 charge) and up quarks (+2/3 charge).
I did attempt to make sure its a valid line of questioning by privately asking mfb...
& I'll ask all the questions up front so as not to annoy the moderators with my follow up questions.
So...
General question to members, when you look at the results and the interference pattern of the double slit experiment for electrons. Does anyone have information on what the empty space is on the screen. The electrons fixed location on the screen shows gaps always. I watched one persons theory...
My concern is an electron tube.
From what I understood so far, gas molecules will have an average velocity derived from the Maxwell distribution, and that velocity will influence in the electron collision frequency.
I can't see clearly though how the electron velocity itself in the presence...
I'm trying to understand electron spin. I understand that if you try to explain the intrinsic angular momentum of an electron, you end up with the surface spinning several times the speed of light.
However, calculations always seem to be done classically. Shouldn't it be done relatavistically...
Dear Sirs,
After my theoretical post on vacuum diode electron flow, I decided to try and measure it physically. I didn't have a vacuum tube, so I improvised with some tungsten wire, aluminum sheets and some screws and the result was usable. Obviously the tungsten wire fails after some time due...
Saha-Boltzmann equation describes the ratio of number densities between any two consecutive ionization states and its product with the number electron density i.e.
$$n_e\frac{n_{i+1}}{n_{i}}$$
Here, ##n_e## is the electron number density, ##n_{i+1}## is the number density in ##i+1## ionization...
Dear Sirs
I have been going through the "radiotron designers handbook", but I can't seem to find the answer to the doubt I have about the electron flow of the source Vp. Kindly consider the below two circuits, the difference is the polarity of Vf.
Question: In both circuits, the electrons...
Dear Sirs,
Maybe this is general knowledge, but I couldn't find the answer where I looked, so please bear with me.
Consider a circuit consisting of a mechanical generator (some spinning magnets and coils) and a wire across the generators output. At some point the wire gets hot and starts a...
How does the electrons interact in QFT? if they are not localized? For example, when one electron repels another or does an atom repel another atom? How do electrons find each other for interaction?
Hello there!
I'm trying to check the first order (1 loop) correction to the electron magnetic moment. I'm following Schwartz and Peskin, but both of them have a point where they hide the calculations, and I'm not sure if my calculations are correct.
The point is exactly this:
I don't know...
Homework Statement
In the problem, an election is moving though 2 charged plates
vertical electric field amount is given and its perpendicular to the electron’s original horizontal velocity. The initial speed of the electron is given and the horizontal distance it travels is given. Then it...
My understanding of the QFT model of a free electron is that there is a localized higher energy level in the electron matter field which couples to the EM field in two ways: (1) the coupling allows the electron matter field to 'feel' a force from an outside EM field and accelerate in response...
Homework Statement
Using free electron model find the number of electron quantum states per unit volume in ##[\varepsilon_F, \varepsilon_F + \Delta \varepsilon]## energy interval of sodium. Fermi energy of sodium is ##\varepsilon_F = 3.22 eV##, and energy band width is ##\Delta...
Hello there,
I'd like to model a simplified version of a "Magic Eye" tube (e.g. without the amplification triode, and for a start, 2 dimensions only), or the visible display behavior.
What I'm talking about:
https://en.wikipedia.org/wiki/Magic_eye_tube#Operation
Here is a nicer depiction of...
Homework Statement
What is the magnitude of the momentum (in kgm/s) of an electron traveling at 0.8c
Homework Equations
p = mv
The Attempt at a Solution
see photo. I said A but the answers said B.
Can anyone tell me, What quantum state really is? Is it applicable for all sub atomic particles? Then, Can anyone explain how two electron are never in same quantum state. And Does proton or neutron follows the same law as electron for obtaining unique quantum state.
If I throw the electron from electron gun with some acceleration .Will it maintain it's constant acceleration? If yes then it radiates photons from where will the electron gets energy to constantly radiate photon? If not then why?
Hello everyone. I'm having trouble understanding this example: https://ecee.colorado.edu/~bart/book/book/chapter2/ch2_5.htm#2_5_2
In this system of 20 electrons with equidistant energy levels, how is it known that there are only 24 possible configurations, and how are those configurations found?
Can we could interfere electron with photon, this question is come from logic both are waves. Is anyone did that before.?(I know that electron isn't a scalar wave)
Hi,
I've been interested in the science behind electrons/magnetism for quite a while. I've been learning quite a bit from various sources online. However there is one thing that's really nagging me.
Magnetic fields result from moving electrons. That indicates that a permanent magnet has...