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.
The oscillator's initial energy can be found by considering when all of its energy is potential energy.
Eo = (1/2)kA2 = (1/2)mω2A2 = (1/2)me(2πν)2A2 = 2meπ2ν2A2
where me is the mass of an electron. With this in mind, the energy dissipated after one cycle is given by
ΔE = E(0) - E(1/ν) = Eo -...
Hi. I would love if someone could check my solution since me and the answer sheet I found online don't agree.
The probability is given by the triple integral
\begin{align*}
\int_0^{r_b} \int_0^{2\pi} \int_0^\pi |\psi (r)|^2 r^2 \sin{\theta} \,d\theta \,d\phi \,dr &= \frac{1}{\pi...
An electron is shot horizontally. There is a proton located somewhere else, but not in the horizontal path of the electron. Is there a distance of closest approach, and how do you derive it? A physical explanation would be appreciated too.
I am thinking about how an electric field has energy associated with it. If a single electron exists alone in a remote vaccuum, I believe it has it's own electric field surrounding it, and that this field has an energy content associated with it. My question is; does this electric field store...
From what I understand, electrons are negatively charged, however, I have recently come to learn that electrons also have a spin which creates a magnetic field around each electron. I don't understand how the electron can be a negative monopole, yet have a completely independent magnetic field...
Hi, I tried to solve this exercise but I'm not sure about the process.
First of all, I imposed that "K = E":
so that "v = √ ( (2q ∆V)/m))"
then I replaced in "r = m v / (| q |B)", v with "√ ( (2q ∆V)/m))", and found out that R = (2√(2)) r.
Then for the second point,
I imposed Lorenz Force...
In QFT where the electromagnetic field is mediated by virtual photons, is it possible to describe the larmor precession of an electron as a series of emission and absorption of virtual photons? how does the spin angular momentum "evolve" over a series of events? This feels like a challenging...
Basically the thread title. For some background, I'm trying to model laser-material interactions, where I'm assuming that the laser is interacting with a free electron gas (copper). To model the interaction, I need to determine the properties of the electron gas, such as the heat capacity...
Coulomb's law for three dimensional space is an empirical law that describes the forces between two stationary point charges and is defined as:
\vec{F}=\frac{K q_1 q_2 (\vec{r}_1-\vec{r}_2)}{|\vec{r}_1-\vec{r}_2|^3}
From Coulomb's law, the magnitude and direction of an electric field produced by...
So as the summary suggests, I am studying Electromagnetism, magnetic properties of matter and Magnetization vector in particular.
As a first example and to introduce the Magnetization vector (M), my textbook shows a ferromagnetic substance in a uniform magnetic field (B).
Then, every atom of...
In Theoretical Minimum: Quantum mechanics, Leonard Susskind describes an electron in the higher energy spin state in a magnetic field radiates a photon of energy ##\hbarγ|B_0|## and flips into the lower energy spin state. I am wondering if this photon is related to the "virutal photon" that...
Hello, I'm new here and honestly I'm not a physics student. I'm studying engineering and so, understand little of physics. I am trying to find the bond force of graphene's free electron. That means, the electromagnetic force by which the electron is bound to the nucleus. I can only calculate it...
Electrostatic repulsion of two electrons is about 4.17*10^42 stronger than their gravitational attraction, and is mediated by massless carriers. Black holes preserve charge, and charging a BH with even a moderate electric (negative) charge will result in BH repulsing electrons instead of...
Any spinning item, proton, electron, even planet, has angular momentum that creates force. How can an electron exist in a random orbital cloud around a spinning proton if it has an angular momentum and requires force to alter from any circular orbital plane (like a planet orbiting a star)?
I am only asking about part e. If you are short on time, you can read through parts a - d, to get an idea of what is happening, and then attempt part e directly.
I have solved parts a - d. If you would like to check your answers, the answer to part c is [rne^2 / 2e0] [ 1 - (v/c)^2], and the...
Energy is equal to Planck’s constant times the number of waves in 1 sec. The time scale for electronic excitation is far shorter then one second. So when we talk about the excitation of an electron from a lower level to a higher level occurring at a certain energy, are we talking about the...
As we know that An electric current is a flow of electric charge in a circuit and In electric circuits the charge carriers are often electrons moving through a wire.
Now, since we know that Like charges repel each other then how do the electrons flow through a wire since they are like charges...
So I can find the initial momentum using p=h/wave = 4.98 x 10-23. Now my problem is that I don't know the final momentum of the photon nor electron, I just know the photon is scattered at an angle of 34 degrees.
I know how to solve this problem if I was given the final wavelength of the light...
In absence of a positive electric field created by proton what type of behavior an electron shows? I am talking about a free electron like from a electron gun in deep space . Pauli's exclusion, orbitals, energy level etc. which are normal in an atom for electron will be absent for an electron...
I am trying to draw the Poynting vector field for a single electron in free space between two capacitor plates. The electron is moving (and accelerating) to the positive plate at the right. I expected the Poynting vector field lines to converge to the electron, because that is where the work...
Here's the question ^
My first thought to solving this is to use Heisenberg's uncertainty principle. $$\Delta x \Delta p = \frac{h}{4\pi}$$ Now, we approximate ##\Delta x = \frac{L}{2}##. Then, plug and chug we end up with:$$p =\frac{h}{2\pi L}$$
I thought this was it, especially because this...
On the first attached page ##\mu_z## is associated with orbital angular momentum (Eq. 41.34). On the following pages (Eq. 41.38) it is associated with spin angular momentum? Are these both part of the same thing? I tried to read further but the book does not address this. In example 41.6 it...
So this is more of an intuitive question rather than a mathematical one. I present the problem.
Assume I have 2 charges of charge +q at a distance r from each other on the z axis. Position of two charges is (0,0,r/2) and (0,0,-r/2). Assume now that I want to calculate the force these two...
So I read that Bohr's atom has discrete energy levels that an Electron can orbit at and that each level has n amount of sublevels (if n = 2 then there are 2 sublevels). Does the sublevel that the Electron is in have to do with it's mass? Does an electron in energy level l and sublevel d have...
It's been troubling me for a while, is there some kind of intuitive heuristic picture of why the electron spin g-factor is 2? I remembered this question because of the thread about the nature of spin. One of the early models of spin that were proposed was that it represented the electrons...
Thank you for reading :bow:
Section 1
To find the energy states of the particle, we define the wave function over three discrete domains defined by the sets ##\left\{x<-L\right\}##, ##\left\{-L<x<L\right\}##, and ##\left\{L<x\right\}##. The time independent Schrodinder equation is...
Hello! I just started reading some molecular physics and I am a bit confused about the electron angular momentum in diatomic molecules. Let's say we have just 2 protons and an electron for simplicity and we are in the Born-Oppenheimer approximation, so we assume that the nuclei are fixed in...
1. Do electron orbitals ever change in _shape_? Specifically, does a solid have the same orbital shapes as a liquid?
2. Are there any factors that would change the _size_ of electron orbitals?
Am I right in thinking that all photon detection methods depend on a photon displacing an electron, that then displaces other electrons to give a detectable electric current pulse?
I'm looking for an estimation or simulation of the magnetic field in the horizontal plane just above a typical lens in a transmission electron microscope. A rough cross section of such a lens can be seen here: electron lens - Bing images .
The lens is cylindrically symmetric around the vertical...
Homework Statement:: I am studying on my own, so I don't have a specific homework statement, but want to make sure I am thinking about things correctly.
What I am wondering is if you have equivalent wires, let's say both are made of copper, and one wire has three times the voltage of the...
The pie chart in this link shows that about 99.95% of the total error of g-2 of the muon in the theoretical prediction is due to the uncertainties in the hadronic corrections. What is this number for g-2 of the electron? Maybe this number exists also for tau particles?
The new value of fine...
At present i am only attempting the part a, i want to use the equation
##F=ma ; qE = ma;## ---> eq1
The electric field is given by the formula
##E = -\frac {dV} {dx} ##
##v = \frac {dx} {dt} => dx = v_0 {dt}## ---> eq2 (?)
##E = -\frac{dV} {v_0 dt}##
Here ##V = -V_m \sin(\omega t) ## hence...
I am wondering if one of the prerequisites of the double-slit experiment, when done with electrons, is that the beams must be in a dark vacuum tube so as to not destroy the interference pattern. I am trying to learn if the beams will lose their interference pattern because the particles of the...
So I know current is just coulombs/second. Electrons are also in the unit of coulombs, so I can get coulombs to cancel.
7.9C/s/1.602E-29C = 4.93133E29 1/s
Now I just need to get mol on top. There are 6.022E23 electron in a mol so 4.93133E29 1/s / 6.022E23 atoms/mol = 8.1889E5 mol/s.
Now my...
I had another excercise of the long list of the same topic (solid state physic) where I need a bit of help. All other excercise where about interband transition, dispersion relation, refracting and absorption coefficient, x-rays and so on, and I managed to solve them or I think I will be able...
Hi! I've been browsing the internet for information about supernovae and I came across this chart describing 4 types of core collapse causes (the chart may have copied weirdly because not all the information fits into this text box):
Cause of collapse
Progenitor star approximate initial mass...
So, as far as I think I understand, an electron that passes through a Stern-Gerlach magnet, will not have a value for its spin until that spin is measured? Does that mean the electron has no position (as given by the SGM) until measured, or that the electron does not even exist until measured?
By Classic Coulomb's Law there exists negligible yet non zero force of attraction between two unlike charges in-spite of the distance.
However for electrostatic attraction to work we need at-least one Faraday Tube(Lines of Forces) between the attracting charges, does that means...
In the picture below, the direction of the magnetic field lines can be determined by using the right-hand rule with the thumb pointing in the direction of the current.
If we use the right hand rule in the picture below, thinking of the yellow arrow as the current, we would not get the correct...
Why is terbium's electron configuration [Xe] 6s2 4f9, with no electrons in the d subshell and one extra in the f sub shell, while uranium's electron configuration is [Rn] 7s2 5f3 6d1, with one electron in the d subshell and none extra in the f subshell?
Are lanthanum and actinide d block...