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.
[Mentor Note -- Two threads started by partners in a class have been merged into this one thread, since they are working on a shared solution to turn in]
Good day, all
I am familiar with both of terms that I speak of in title. But I cannot find a full answer, so I might as well ask the PhD'ers here. What is really happening in Zener and Avalanche breakdown? I have read Guide to Zener Effect and Avalanche Effect and still feel confused.
And yes I...
When I try following numbers from internet then I don't get an expected answer.
## \mu_0 = 1.25663706 × 10-6 m kg s^{-2} A^{-2}##
##q =1.60217662 × 10^{-19} coulombs ##
##r=2.82x10^{-15} m##
Velocity of that electron is given in question
##\vec v= 2 \times 10^6 \\ \mathrm{ms^{-1}}##
Since...
B equals 50*10^-7 T (at first instance)
Fm equals 8*10^-20 N (at first instance)
I know Fm is perpendicular to the velocity, and I know the estimation of the trajectory (somewhat similar to the curve y=lnx).
Since I think vertical velocity will be constant, only changing the x component, I...
Hello All,
I am aware of databases which list possible gamma-gamma coincidences for desired isotope. For example: here provides a table at the bottom with all possible gamma-gamma coincidence for Co-60.
Question is, are there any similar databases/tables for electron coincidences with...
Imagine a magnet moving up and down so that its flux 'B' cuts the copper rod to produce an alternating emf, suppose if the movement is fast enough such that its frequency equals to the electron spin resonance frequency given by F = B x 2.8 Mhz per gauss, neglecting skin effect, more copper...
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...
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 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...
Modern batteries use double-sided anode and cathodes for greater energy density. Series wiring of batteries is typically accomplished by connecting the anode of one cell to the cathode of another. However, can series be accomplished by stacking double-sided anode and cathode alternatingly with...
It will try to produce a neutral atom but it depends on the amount of energy that electron is shot at the atom, if it is great enough energy for ionization it will produce cation, If it is not enough for ionization it will make a neutral atom or anion, I think.
Hello, this problem is causing headaches, it would be very helpful if you could tell me if you know of a book where you can solve it. Maybe my English is lousy because I use a translator. Thank you very much.
I've written out the half reaction
8e- + 9H+ + SO42- = HS- + 4H2O
and I know the logK = 4.25 (that's the constant mentioned in the prompt)
I've written out the equilibrium statement of 10^4.25 = ([x^1/8]*[H2O^1/2])/([10x^1/8]*[e-]*[(10^-8.2)^9/8]
However, from there, it seems like I have two...
Does the negative terminal of a battery have a negative charge due to having a surplus of electrons? If so, then why do the surplus electrons from the negative terminal of the battery not discharge to the human body or earth (which have a neutral charge) when touched?....thereby causing the...
Homework Statement:: Consider an electron trapped in a one-dimensional finite well of width L. What is the minimum possible kinetic energy of the electron?
A) 0
B) Between 0 and h^2/8mL^2
C) ≈h^2/8mL^2, but it is not possible to find the exact value because of the uncertainty principle
D)...
Would this be an accurate portrayal of measuring the spin of an electron with a SG detector?:
The electron is in a superposition of spin-up and spin-down;
Upon entering the magnetic field of the SG detector, the electron enters a superposition of an upward trajectory and a downward trajectory...
I've been researching the proof of subatomic particles given the fact that we have never seen them before. It has always been recognized that protons, electrons, and neutrons exist; but I question how we know for certain they exist.
Across my studying I've realized that in 1897, J. J. Thompson...
We know that an electron and a positron will annihilate and emit gamma ray. But the electron and positron possess initial kinetic energy meaning that it is difficult for them to really collide in each other. Just like earth is not dropping into the Sun even with the gravitational pull. So I am...
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...
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...
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...
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...
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...
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...
If the mass of the electron has been changing during the evolution of the universe, then the orbits of the electrons would also change, which will shift the light spectrum of each atom.
Could this explain red shift of far galaxies, and the shift is not because the universe is expanding?
Henry
Homework Statement
For silicon at T=300K with donor density ND=2×109cm−3, acceptor density NA=0 and ni=8.2×109cm−3, calculate the equilibrium electron and hole concentration
Homework Equations
n_0=\frac{N_D-N_A}{2}+\sqrt{\frac{N_D-N_A}{2}^2+n_i^2}
p_o=\frac{n_i^2}{n_0}
The Attempt at a...
I couldn't fit the whole question, it should say
"How close does an electron have to get to a proton to be attracted to it"
And I know it can depend on the speed and direction they are traveling. Can we just pretend they are stationary for this answer please.
By attracted I mean the electron...
pg. 243 Falconer, I. (1987) Corpuscles, Electrons and Cathode Rays: J.J. Thomson and the Discovery of the Electron. The British Journal for the History of Science (BJHS, 1987,20,241-276). "One of their most important properties is that they are deflected by a magnetic field. This provided strong...
Homework Statement
An electron and a proton are each placed at rest in an electric field of 687 N/C. What is the velocity of the electron 56.5 ns after being released? Consider the direction parallel to the field to be positive. The fundamental charge is 1.602×10−19 C, the mass of a proton is...
Homework Statement
Hello PF!
Got a two-part question involving calculating the electric force on a electron when placed in an electric field of 0.75N/C to the right, and the acceleration of said electron. Our values are E=0.75N/C, q=-1.6e^-19, m=9.1e^-31 (charge and mass of electron)...
Homework Statement
Is there a minimum value for the total energy of the electron (in this analysis)?
The previous parts:
Use Larmor formula to find ##\frac{|\Delta E|}{K}##, where ##|\Delta E|## is the energy lost per revolution.
the result is ##\frac{8\pi v^3}{3c^3}##.
##\frac{v(r)}{c}## was...
Homework Statement
Find an expression for the time it takes for an electron to spiral in from an initial radius ##r_i## to a final radius ##r_f##. Write your answer in terms of ##r_i##, ##r_f##, ##m_e##, e, and c.
Homework Equations
Larmor Formula:
$$\frac{dE}{dt} =...
Homework Statement
Cylinder electron gas with density of ne= 1010 and radius or r=1cm is inside magnetic field of B=104 Gauss.
If we change the electron gas with
(i) muon gas
(ii) proton gas
does the Drift Velocity change?
Homework Equations
[/B]
Boltzmann equation of density...
Why all particles of same type identical? All electrons are identical to each other, all protons are identical..etc. It is as if they are copy pasted from each other!
For me this is one of the biggest mysteries ever, why we don't detect more massive or less massive electrons?
Is it related...
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 in to visible light. So my question is how does the information by which I mean (the...
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...
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...
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...
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...
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...