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.
No physicist has ever seen an electron. Yet, all physicists believe in the existence of electrons. An intelligent but superstitious man advances this analogy to argue that 'ghosts' exist even though no one has seen one. How will you refute his argument?
So I read a couple of explanations of how night-vision equipment works. Unfortunately I don't remember the sources but my recollection/understanding is that infrared light is converted into electrons and then into visible light. So my question is how does the information by which I mean (the...
If a beam of electrons starts to accelerate from rest due to a uniform electric field in vacuum will the electrons feel any mutual repulsion or attraction? Will the beam first expand then contract?
If yes, how does this happen? This was a question under magnetism head.
I came across your site while looking for information on how to advance our ability to view beyond the capabilities of current electron microscopy technology. I do not know where to start asking but I hoped you could point me in the right direction. I’m about to enroll in university classes and...
Homework Statement
A proton is projected perpendicularly into a magnetic field that has a magnitude of 0.30 T. The field is then adjusted so that an electron will follow a circular path of the same radius when it is projected perpendicularly into the field with the same velocity that the proton...
Phonons on their own lead to the common heat equation. One sees that for example in insulators or non doped semiconductors.
However in metals (or conductors), the electrons are the ones that are mostly responsible for the heat transfer, which extremely surprisingly to me, is also of the form of...
Please help me in understanding the function of anode. As in image attached you see, once the electron beam is emitted from cathode and filtered by grid, it enters into the one or series of anodes. As anode is positively charged, so, to my understanding it has no electric field inside its hollow...
Hi to everybody ! I was thinking about something which confuses me about wave emission.
The question is simply the following:
Does an electron emit light when it accelerate? or just during its deceleration? or maybe when acceleration and deceleration alternates in some order? I'm not really...
Hello,
in class we learned about the hydrogen atom and in particular the quantum states describing the electron in hydrogen atom (we denoted them as usual by 1s, 2s, 2p etc.). Whenever we talked about state transitions of the electron, like transition from 1s to 2p state, we imagined an...
This is a question I was looking at based on Relativity and John Wheeler's one-electron universe theory.
https://en.wikipedia.org/wiki/One-electron_universe
My question is this. The faster you move towards the speed of light, wouldn't everything in the universe contract to a single particle...
When light is shown through hydrogen gas, three colors of light appear. The issue I have with this is that hydrogen has one electron, meaning somehow the electron has to be emitting all three of these colors simultaneously. This, however, would be impossible since a single electron can only make...
O-- 2s2 2p5
F-- 2s2 2p6 (Fully filled hence more stable.)
Since F- is fully filled as compared to O- wouldn't it require more positive electron gain enthalpy to gain one more electron than O-?
However, the correct answer is given (A)
Please tell me how.
Thank you for reading.
I have a simple two-part question, or two simple questions.
1. What is energy?
2. What is charge?
The charge I'm referring to is the charge on charged subatomic particles. And atom's charge is defined by the number of electrons and protons present in it. But an electron itself is called a...
I beg your pardon for not writing out the math explicitly in the following. I started to do so, and realized that it would take me hours to debug my attemps at Latex! And I hope that the my explanation is clear enough that it's not needed.
I've been working through R.E. Turner's "Relativity...
Homework Statement
Compare and contrast a 2.2 eV photon with a 2.2 eV electron in terms of wavelength (m).[/B]
Homework Equations
p = h/λ
λ = h/mv
The Attempt at a Solution
For photon:
p = h/λ
λ = h/p
λ = (6.63 x10-34) / (1.17 x10-27kgm/s)**
λ = 5.67 x10-7 m
**I have already...
Hi everyone,
I often work on a SEM, a type of microscope which is based on electron acceleration between an electron source and the sample you are working on. For this reason and since a few weeks I was wondering how an electron (in term of speed) behaves in a constant and linear electric field...
This paradox may have come from Feynman's Lectures on Physics, or I may have dreamed it up myself. I am not sure. It has been around for a while and if you have already seen it, I apologize. I am not aware of any resolution.
An electron is at rest in a gravitational field. We know from...
I'm watching a lecture and the professor is talking about generic quantum states as
|\psi>
He's making the point that this state is very generic. It can represent anything. He references some examples like the polarization of a photon and the path of a photon and the spin of an electron...
Hello all,
I have a question. Consider an electron in a shell of an atom has energy as 1.0ev and in the next shell it energy should be 2.7eV and the further next level energy is let's say 3.1eV. Means an energy gap of 1.7eV is their between first and second level and an energy gap o 2.1 eV is...
Homework Statement
Homework EquationsThe Attempt at a Solution
de Broglie wavelength λ of a particle = h /P
a) since mass of proton is more than electron and speed is same , momentum of proton is more . De Broglie wavelength of proton will be less .
b) wavelengths will be same .
c) Using...
Homework Statement
A filament in a light bulb uses a length of wire 6.0cm. The potential difference across the filament is 240V. What is the force on an electron in the filament from the imposed electric field?
Homework Equations
F= qE
E = V / d
The Attempt at a Solution
Hello everyone...
Good evening!
The question states: 9. Electron in bound orbit about proton. Suppose that an electron moves in a circular orbit about a proton at a distance of 2 X l0^-8 cm. Consider the proton to be at rest. (a) Solve for the velocity of the electron by equating the centrifugal and...
I feel like I must be missing something obvious, but I can't figure it out. I have the speed of an electron, and to calculate its frequency i used p = h/λ, then subbed in p =mv and λ= v/f. Giving me the equation f = mv2/h. However, I also could use E = 1/2 mv2 and E = hf to give me the equation...
I'm studying plasmons from "Haken-Quantum Field Theory of Solids", and i need some help in the calculation of the equation of motion of eletrons' density
\begin{equation}
\hat{\rho}_{\overrightarrow{q}} = \frac{1}{\sqrt{V}} \sum_{\overrightarrow{k}}...
Homework Statement
I was doing the Milikan Oil Drop Experiment from a simulation this site: http://scienceclub.ucoz.com/index/0-109. I tried calculating the charge of the electron but it was from the real value.
Oil Density: 920 (kg/m^3)
Viscosity of Air: 1.81×10−5 kg/(m*s)
Distance: 0.0025 m...
I’ve been curious about understanding the mechanism behind themionic emission from what I have read I found that themionic emission happen when the energy from added temperature excess the work function of the material. I also readed when temperature excesses 1000k themionic emission happens but...
The energy of electron-positron colliders is limited by the acceleration gradient (energy per distance) and the length of the accelerator (=the cost). In the past the energy mainly increased from making accelerators larger. Much larger accelerators than today get prohibitively expensive...
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