What is Electron: Definition and 999 Discussions

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.

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  1. G

    What does a body "emits" when falling down?

    I explain it better. If we bring an electron from higher to lower energy level, the energy gap will be emitted as electromagnetic wave, because of the conservation of energy. When the same situation applies for a physical body, for example letting if falling down from some height, what does it...
  2. J

    B Electron Gun for a Grade 9 Physics Project?

    I am in grade 9 in the IB curriculum and next year I have to do something called a "Personal Project" where I have to make something and explain why I did it. I would like to recreate the double slit experiment. However, I have to obtain a electron gun and they are quite hard to come across. So...
  3. amjad-sh

    Thermodynamics of the free and independent electron gas

    Homework Statement (a) Deduce from the thermodynamics identities: ##c_v=(\frac {\partial u}{\partial T})_n=T(\frac{\partial s}{\partial T})_n## and equations: ##f(ε)=\frac {1}{e^{ε-μ/k_BT}+1}## and ##u=\int \frac{1}{4π^3}ε(k)f(ε(k)) \, {d \vec k}##...
  4. T

    Electron in a Quantum State: Finding Eigenvectors and Eigenvalues

    Homework Statement If possible could someone have a look at my working for this problem, I am not sure if I have carried out part b) correctly. I have done all three problem and carried through my solution to b) just to see if it did simplify out, which it didn’t which make me think I may have...
  5. Murphy.T

    Potential Energy of an Electron near a negative source charge

    If an electron starts from rest 85.0 cm from a negative fixed source charge of -0.135 micro coulombs we use the equation ke final - ke intial + pe final - pe intial. In solving you use ke = pe which appears to cancel out the inital kinetic and potential energy but how can the initial potential...
  6. F

    The trajectory of an electron and a proton between two charged sheets

    Homework Statement Homework Equations - The Attempt at a Solution (A) , because the proton moves in a direction opposite to the electron. Right ?
  7. G

    I I want to read about the electron nucleus interaction

    My unreliable memory is that although Schrödinger's equation treats the interaction between an electron and the nucleus as unquantised, it is more generally thought to be mediated by an exchange of quanta between electron and nucleus. I want to check on this and get a better understanding. Can...
  8. Ryan Doucette

    Nuclear Fusion: Electron Thermal Transport Terminology

    I am an undergrad physics major in my final semester currently taking Intro to Thermodynamics. As a final project, each student must choose a topic related to thermodynamics that is more advanced than what is covered in the curriculum and write a paper and present our findings to the class on...
  9. Cheesycheese213

    Positive/negative electron transfer?

    Can a positively charged and negatively charged object charge by conducting? If so, is it possible to make a neutral charge again?
  10. C

    Finding the angle of an electron striking a plate

    Homework Statement An electron is fired at 4.0 x 106 m/s horizontally between the parallel plates, as shown, starting at the negative plate. The electron deflects downwards and strikes the bottom plate. The magnitude of the electric field between the plates is 4.0 x 102 N/C. The separation of...
  11. C

    Determining the magnetic force on an electron

    Homework Statement A magnetic field of 0.0200 T [up] is created in a region.a) Find the initial magnetic force on an electron initially moving at 5.00 x106 m/s [N] in the field.b) What is the radius of the circular path? Make a sketch showing the path of the electron. Homework Equations...
  12. Sandeep T S

    I Photon & Electron: Photoelectric & Compton Effects

    How photon transfer energy to electron in case of photoelectric effect,and compton effect. Is any high level theory which explains this scenario?
  13. DrClaude

    Fermi temperature of a 1D electron gas

    Homework Statement Consider a one-dimensional metal wire with one free electron per atom and an atomic spacing of ##d##. Calculate the Fermi temperature. Homework Equations Energy of a particle in a box of length ##L##: ##E_n = \frac{\pi^2 \hbar^2}{2 m L^2} n^2## 1D density of states...
  14. H

    Understanding solar cell band diagram

    Hi everyone, I have been studying the physics of solar cells for a long time. The only thing that I can not completely understand is the physical operation of solar cell based on band diagram. Can anyone briefly explain the movements of carriers from one electrode to the another based on band...
  15. G

    Acoustic electron trap question

    Hi, I wonder is it possible to trap electrons in vacuum using acoustic waves as it is possible to trap them using electromagnetic waves? imagine a vacuum tank and electrons injected say from a thermionic emission (electron gun) and having one or two transducers set apart to produce satnding...
  16. Vectronix

    B Do atomic nuclei transfer momentum to electron orbitals?

    Do protons' inherent gyroscopic nature produce progressive ripples in the electromagnetic field? If so, then is there an ensemble of transverse electromagnetic undulations arising from the proton's angular momentum that contribute to electronic orbital energy in, say, a hydrogen atom? If these...
  17. G

    Understanding Free Electrons: Movement and Interaction with Nonconductors

    Can we call it free electron that moves between nonconductor by friction?
  18. L

    Kinetic energy in electron volts

    Homework Statement How much kinetic energy is in electron volts? Homework Equations Kinetic energy = 1/2 mv2 1 electron volt = 1.6 x 10-19 J The Attempt at a Solution [/B] It's a bit unclear to me what the question is asking, since no context at all is given. It's one of the questions in...
  19. R

    A Electron charge vs quark charge

    I have been trying to understand some of the basic differences in the fundamental nature of leptons and quarks. One article on this issue compares leptons and quarks as "oranges vs apples" to which I basically agree except for one aspect. How can the charges of the quarks be 1/3 or 2/3 the...
  20. devan

    I Width of one electron shell of a hydrogen atom

    I'm quite new to quantum mechanics. I have a question, I'm coding a small game with my friends and I do understand the orbitals and I've even written a function in java to simulate the probabilities of ONE of those diagrams, but I do not know my scale just yet, can anyone tell me the width of...
  21. yecko

    Electron configuration of Fe(2+)

    Homework Statement Electron configuration of Fe(2+) Homework Equations spdf configuration The Attempt at a Solution 1s2 2s2 2p6 3s2 3p6 3d3 4s2 But from (https://www.thestudentroom.co.uk/showthread.php?t=1232420), it says 1s2 2s2 2p6 3s2 3p6 3d6. isn't electrons fill up 4s shell first...
  22. T

    Electron spin probabilities

    Homework Statement After beta- decay electron and antineutrino comes out, electron is moving along z axis and it is moving with velocity v. It's spinor is ## \mid\chi\rangle=A\left(\frac{\sqrt{1+\frac{v}{c}}\sin\frac{\theta}{2}}{\sqrt{1-\frac{v}{c}}\cos\frac{\theta}{2}}\right) ## where A is...
  23. G

    Are the electrons in an electron microscope coherent?

    In an old fashioned electron microscope (the type I was meant to understand at university 50 years ago), are the electrons coherent, or do we just consider an electron interfering with itself? If they are coherent, how are they made coherent?
  24. A

    I What happens when we observe an electron?

    I have learned about the principles of quantum mechanics from two sources. The first is a book called quantum mechanics concepts and applications. The second is prof. Allan Addams lectures in MIT. But they have different opinions about what happens to the interference pattern of electrons when...
  25. Sritika

    I De-Broglie Wavelength of a captured electron?

    For a proton to capture an electron to form a neutron and a neutrino (assumed massless), the electron must have some minimum energy. For such an electron,how can the de-Broglie wavelength be found out?
  26. G

    Electron Diffraction Intensity and Reciprocal Lattic

    Homework Statement Low-energy electron diffraction (LEED) experiments are carried on to study a deposition of argon (Ar) and xenon (Xe) on the surface of a graphite single crystal. In the regime of vapor pressure considered, 75% of Ar and 25% of Xe are adsorbed on the (hexagonal) crystalline...
  27. starvingautist

    The potential created by an electron in hydrogen

    Images aren't embedding properly, so forgive the urls. This is the question I am attempting to answer: https://imgur.com/a/mEcAl and this is the start of my answer: https://imgur.com/a/8MoDi so.. I wasn't expecting just to get the coulomb potential at the end. This is supposed to be the...
  28. A

    Do electron absorb the entire photon energy?

    I couldn't type the whole question | -or jusg part of the spectrum during the working of a solar panel
  29. PhilQ

    A Tunneling Electron Energies

    If we have a MIM device of Ti/Nb2O5/Ti at room temperature (300K), with a measured barrier height(s) of 0.0eV, the insulator thickness is say 2nm, and let's call the electron affinity of Nb2O5 4eV, and the Work function of Ti 4eV (for the sake of a simplified question), what is the average /...
  30. A

    Electron and proton penetration

    Homework Statement Which, of an electron and a proton (of a few Mev), is more likely to penetrate further into matter if they both have: a) The same energy b) The same speed Homework Equations Bethe-Bloch formula. Total stopping power = collision loss + radiation loss (de/dx)t = (de/dx)c +...
  31. F

    Is the Rydberg formula true for electron absorption only?

    Since we know that when an electron goes from the ground state (hydrogen) n=1 to n=3 for example, we have ΔE = E3 - E1 by manipulating the equation we get Rydberg's formula 1/λ= R (1/ni2 - 1/nf2) (where R is Rydberg's constant) My question here, if the electron goes from higher energy state...
  32. Jianphys17

    Question on classical electron radius

    Hi at everyone, why on wiki there is written: " According to modern understanding, the electron is a point particle with a point charge and no spatial extent. Attempts to model the electron as a non-point particle are considered ill-conceived and counter-pedagogic " I don't understand this...
  33. C

    Does electron gas in metals experience viscosity?

    Does electron gas in metals experience viscosity? Also, does highly charged plasma experience viscosity?
  34. Physics Student 1234

    The electron momentum is E/c, so that its speed is....

    Homework Statement Homework Equations E = γmc2 p = γmv K = E - mc2 E2 = c2p2 + m2c4 The Attempt at a Solution I have completed most of this question, but I am struggling to get the required result to the final part of the question.[/B]
  35. Wrichik Basu

    Reason for Optical Isomerism (at electron level)

    I have been studying Optical Isomerism recently, and I have got one question, answer to which was not in the books that I have. I have understood what the phenomenon is, and that, how one can determine whether the plane of polarised light is rotated, and how to tell from the structure whether...
  36. M

    A What is the value of optical effective electron mass for tin

    What is the value of optical effective electron mass for tin metal (white tin)? What is the value of mean free path for electron of tin metal? At least give me some websites or papers where I can find it?
  37. B

    A R value in electron positron annihilation

    In the calculation of R=σ(e+e-→hadrons)/σ(e+e-→μ+μ-) from BaBar experimental data at a center of mass energy of √s≈10 GeV i obtain R=5. Theoretically I should get a value of R=10/3. I know it has something to do with the resonances of ϒ mesons shown in the plot attached, but I don't know how to...
  38. J

    Determine energy levels of a electron in a hydrogen atom

    Homework Statement When an electron in a hydrogen atom makes a transiton between two levels with prinicipal quantum numbers n1 and n2, light is emitted with wavelength of 658.1 nm. If we assume that the energy levels of the atom are in agreement with the Bohr model, what are n1 and n2...
  39. C

    I Energy of an electron with Schrodinger's equation

    Hello, I was trying to make a simple model of an electron tunneling through several potential barriers. The electron will flow through a conductor to a heterojunction of possibly semiconductor/oxide layers. I assume the electron is coming as a plane wave from the left with some energy E. We know...
  40. M

    What Is the Escape Speed of an Electron from a Charged Glass Sphere?

    Homework Statement What is the escape speed of an electron launched from the surface of a 1.0-cm-diameter glass sphere that has been charged to 10nC? Homework Equations Given: d= 1.0cm r= 0.05cm= 0.0005m q1 = 10nC = 10 x 10-9 (sphere) q2 = -1.6 x 10-19 (electron) Equation: U = (kq1q2)/r KE=...
  41. M

    Determining speed of electron in a parallel plate capacitor

    Homework Statement A proton is released from rest at the positive plate of a parallel plate capacitor. It crosses the capacitor and reaches the negative plate with a speed of 50,000 m/s. What will be the final speed of an electron released from rest at the negative plate? Homework Equations...
  42. F

    I What is an optically active electron?

    I was studying the spin-orbit interaction and the Zeeman effect, and came across the concept of optically active electrons. Initially I got the idea that an optically active electron is any unpaired electron. But then, while trying to understand the Zeeman effect in a Cadmium atom, for which...
  43. C

    Force between two charged particle beams -- proton and electron beams

    Homework Statement A proton beam is going from north to south and an electron beam is going from south to north, so in which direction is the electron beam deflected Homework EquationsThe Attempt at a Solution . [/B] I thought an electron...
  44. aatari

    Electric Fields - Electron Passing through deflecting Plates

    Hi Guys, I have attempted the question below. Please have a look at my work and let me know if everything looks fine. Any feedback would be great. 1. Homework Statement Homework Equations F = qv/d a = F/m t = d/v qv = 1/2mv^2 x = vt + 1/2 at^2 The Attempt at a Solution
  45. A

    Accelerated Electron and its Potential Energy

    Homework Statement An electron acquires 3.16*10^-16 J of kinetic energy when it is accelerated by an electric field from plate A to plate B. What is the potential difference between the plates, and which plate is at the higher potential. Homework Equations w =Δv * q The Attempt at a Solution...
  46. Y

    Orbital/Spin angular momentum + magnetic quantum numbers

    Homework Statement A single electron atom has the outer electron in a 4f1 excited state. Write down the orbital and spin angular momentum quantum numbers and the associated magnetic quantum numbers for this state. Homework Equations I don't think there is any relevant equations. I think it...
  47. T

    What will be the energy required to make 1 electron escape?

    Homework Statement Homework Equations E=hc/lamda The Attempt at a Solution I can get the amount of energy incident on the surface (3%of Intensity×Area) What will be the energy required to make 1 electron escape? (4.5eV+hc/250nm )? Then I divide total energy by energy to make 1 electron...
  48. Kara386

    Free electron density conduction band

    Homework Statement How many free electrons are there in the CB? Diamond has a bandgap of ##5.5##eV.Assume the material is at room temperature and that there are ##2 \times 10^{22}## cm##^{-3}## electrons in the material. What does this mean for their use in semiconductor devices? Homework...
  49. Muthumanimaran

    Finding the probability of 1s electron within a cubical volume

    Homework Statement How to calculate the probability of finding an 1s electron within 1 picometer cubic region located 50pm from the nucleus. Homework Equations The probability of an 1s electron within a spherical volume of radius 'a' from nucleus can be find using the expression...
  50. C

    Electron dot structure, Lewis structure

    Which is more correct, teaching the first two valence electrons as paired in the electron dot structure or teaching them as not pairing until forced.
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