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.
Hi,
I have a loose understanding of some things in life.
This in particular regards the electrons in electrical appliances.
Lets say electrons in a Geiger–Müller tube. They way it is described is that radiation interacts with the chamber wall or the gas and knocks out electrons. These electron...
Homework Statement
This problem has two parts.
A laser produces photons having an energy, E = 3.5eV.
a) What is the wavelength of photons produced, assuming that the index of refraction is 1.6? ->221nm
b) If this laser beam is focused on the clean surface of a metal having a work function of...
Namely, are the wave functions of electrons near the Fermi surface spatially distributed in the so-called "active blocks" (CuO2 layers and etc.) or in the so-called "charge reservoir blocks" ? Or any other case?
( EO/(AOx)m/EO with m =1, 2 monolayers of a quite arbitrary oxide AOx(A = Bi, Pb...
Are we able to observe other particles without the use of photons? Are we able to harness electrons or positrons to do this?
I ask because of quantum entanglement. Creating a use out of quantum entanglement seems to rely on observing one of the particles and thus either getting its spin or...
what is wave and how electrons show wave phenomenon within an atom. like in Px or Py or Pz orbital how electrons interchanged from one dumble to another?
what is wave and how electrons show wave phenomenon within an atom. like in Px or Py or Pz orbital how electrons interchanged from one dumble to another?
Hi everyone,
I need help for preparing a Hamiltonian matrix.
What will be the elements of the hamiltonian matrix of the following Schrodinger equation (for two electrons in a 1D infinite well):
-\frac{ħ^{2}}{2m}(\frac{d^{2}ψ(x_1,x_2)}{dx_1^{2}}+\frac{d^{2}ψ(x_1,x_2)}{dx_2^{2}}) +...
Simple level question this:
How many kinds of electrons are there?
Like if 1 Amp = 6.24 x 10^18 electrons and Watts = Amps x Volts then in our local 240V system the watts = 240.
= 0.24 kW.
Now if we take that 1 Amp in an American 120Volt system then the Watts = 120W.
So the same stream...
Homework Statement :[/B]
I have a battery and lightbulb circuit (in series). 12V battery rated at 35Ah.
Ten billion electrons pass a planar cross section of the wire. What is the charge of the 10 billion electrons?
Homework Equations
Q=Ne
I=dq/dt
1A=1C/sThe Attempt at a Solution
Is this as...
electrons in terms of absorption.
To move from a lower to a higher energy level, an electron must gain energy. Oppositely, to move from a higher to a lower energy level, an electron must give up energy. In either case, the electron can only gain or release energy in discrete bundles.
Now let's...
... compared to a opaque materials electrons. Is it the amount of electrons in the atoms shells ?If you have a four inch cubic block of glass, and carbon, light passes through the glass no problem, but the carbon will absorb some red, yellow, green, and blue light, but if you look at the carbon...
Hydrogen electrons can spin-flip and emit a 21 cm photon. Can core electrons in a metal like lithium spin flip? If so, is the energy required to do so similar to hydrogen?
Transition of an electron from the valence to conduction bands (direct transition at a k-point near the band edge) would change the momentum of electron because the sign of the group velocity in valence and conduction bands are opposite. Could one infer that the direction of radiation is a...
What keep electrons move? I read somewhere that in q physics the kinetic energy of an electron mean how much the wave cloud is compressed. If the electron is part of an atom its wave is wide a smeared but if delocalized then its wave is small and its position much more exact.
But the electron...
So I was thinking, if the body has its own electrical currents... especially in the brain, then the brain must have an electrical field that extends infinitely. If that is the case can the brains electrical field interact with the real world and influence it. So for example if the field was...
Hello Physics Forum, I have a quick question for the scientific community that I am unable to find online (likely because the term doesn't exist), but is there are term for the act of an electron moving from one orbit into another when binding two elements? Also I have a very minimal...
Homework Statement
Why is it harder to rip off a paired electron than an unpaired electron? I'm trying to work out why the ionisation energy is lower for chlorine than for argon.
Homework Equations
Configuration for argon: $$1s^22s^22p^63s^23p^6 $$
Configuration for chlorine...
I am making a finite elements simulation of electrons in the bottom of the conduction band of some material. To do so I assume that the electrons move in the bottom of a flat well with their original mass replaced by the effective mass. The idea is to calculate wave functions for electrons...
I have begun studying Ashcroft + Mermin on my own, and am trying to follow the math in the text. They suggest that an electron in a metal with some momentum p(t) and exposed to a force f(t) will at some time later (t+dt) have a contribution to the momentum on the order of f(t)dt plus another...
Homework Statement
Using Maxwell's theory of EM waves, show that an electron while revolving in Bohr's orbit does not radiate any energy. It radiates energy only when it jumps from a higher energy orbit to a lower energy orbit.
Homework Equations...
Lepton Universality and Pauli Exclusion
Put in a possibly oversimplified way, lepton universality says that electrons, muons, and taus all behave in the same way except for mass effects. The question is “Does this apply to Pauli exclusion?”
Due to the Pauli exclusion principle, only two...
Well here's the problem carbon nanotubes possesses a electron - hole symmetry .my question is to what property of CNT'S does this symmetricity attribute to ? in otherwords if we dope this with a material with more electrons / holes what property will change ?
Hey guys. I just want to know why electrons in a coil always follow the turns instead of jumping from one turn to another. I mean, in many cases the turns are very close to one another. Also, if I'm not mistaken, electrons travel the shortest distances. Thank you!
Hello everyone,
I am currently working on a project to design a more efficient method of electricity production in the nuclear industry. I haven't been able to find anything online (and chemistry isn't exactly my strong suit most of the time), but I wanted to know if anyone knows of a liquid or...
Are all electrons perfectly identical? How can we be sure that all electons have the exact same mass electric charge etc. considering that we leave in a world that perfect doesn't exist ... I mean how do we know that electon's A mass can't defer at some point in infinity than electon's B mass...
Now, this is probably a very noob kind of question, but I am just going to say I just don't know how to answer this following series of questions.
If we have a circuit, with a battery and bulb and the wires connected per normal, how do we physically explain the expenditure of energy in terms of...
Homework Statement
what is the speed of an electron with kinetic energy of (a) 100000 eV
Homework Equations
m=m0/√(1-β2)
K=Δmc2
The Attempt at a Solution
plug first into second equation, isolate v and it eventually comes out to be
v=c(1-(1+K/m0c2)-2)
plug in numbers and i get a velocity of...
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?
Homework Statement
In a flame test lab, where different unknown substances are heated and the identity of the substance is determined by the color emitted, what can be some sources of error?
Homework Equations
n/a
The Attempt at a Solution
I need three sources of error, and so far I have...
In case of a semiconductor, the position of Fermi level in between valence band and conduction band doesn't lie in the middle of the band gap due to the difference in the effective masses of holes and electrons. so, whose effective mass is more- electron or hole?
Homework Statement
The problem I have been set is to rework the Drude model using clearly defined scattering statistics.
Homework Equations
The Drude model as we have been given it is in terms of momentum
\vec{p}(t+dt)=(1-\frac{dt}{\tau})(\vec{p}(t)-q\vec{E}(t)dt)+(\frac{dt}{\tau})(0)
Where...
Homework Statement
What number of electrons to balance the equation
##I_2(s)+OH^-(aq)\rightarrow IO_3^-(aq)+H_2O(l)##
The Attempt at a Solution
I see that the oxidation state of I increases from 0 to +5
But, I don't see any reduction at the reaction..
So, I don't understand how to balance the...
Homework Statement
A beam of electrons travels east at speed, v = 6.10x 10^6 m/s . It passes through a magnetic field , B = 0.450T , directed from top to bottom. Describe exactly the path of the electrons motion?
Homework EquationsThe Attempt at a Solution
The path of a charged particle moving...
I am thinking of a time period between two events:
1. After the annihilation of most protons/neutrons with all anti-protons/anti-neutrons, and
2. Before the annihilation of electrons and positrons.
During this period the temperature decreases from T1 to T2. T1 is the highest temperature at...
I understand that the result of the hydrogen emission spectrum experiment was that only certain wavelengths of light were emitted and that led to the conclusion that electrons emit light when they relax and that they absorb light when they get excited. How does that prove that the energy for...
Homework Statement
A stream of electrons is of energy E is incident on a potential barrier of height U and thickness d. Even though U >> E, 5% of the electrons tunnel through the barrier. If the thickness of the barrier decrease to 0.86 d, what percentage of the electrons will tunnel...
Is it possible to ID an electron in ATLAS if it did not leave a track in the tracking system?
I think that the coverage of the tracker is : ##| \eta | < 2.0## (TRT) or ##2.5## (SCT)
for example an event of W+jet would result in Missing Transverse Energy alone + jet if the electron was to leave...
I attached a picture.
In the first figure, we see that the difference between bands is rather large. We see that electrons do not occupy all the energy levels from energy 0 to Fermi energy level. There are forbidden band gaps.
But in the second figure, I see that the electrons occupy...
Just a thought:
The momentum quantum number given for s states is l = 0. If an S state electron dropped in energy, and emitted a photon with l = 1, what would take place?
Am I correct that the electron could only drop to a lower l = 0 (an S state) orbital?
Hi. I am struggling to understand the concept of distinguishability in quantum mechanics. If the wave functions of two particles overlap, those become indistinguishable from what I can understand. So if, in an atom, two electrons occupying an orbital are also indistinguishable. right? But can't...
hi every body
question is :
Consider that 5.5E22 free electrons are confined in a potential barrier of length 3.2A . find its Fermi energy ?the main point is that i was confident about the answer of question .. but the doctor said it is wrong .. he said i should use the relation between the...
All elementary particles, which are not made up by any other particles (electrons, quarks), are said to be zero dimensional and have no size. But why not? Are electrons literally zero dimensional particles with no size?
Homework Statement
a)Find the densities of states 0.08 eV above the conduction band edge and 0.08 eV below the valence band edge for germanium. Be careful with units and be sure to give the units for your answer.
b) Find the volume density of states (i.e. number of states per unit volume)...
Homework Statement
In inkjet printing, a rapidly moving nozzle horizontally squirts drops of ink that form letters and images on paper. A common problem is horizontal white lines running through the print due to a clogged nozzle. Another common problem is paper dust.
(a) Within the context of...