Negatively charged particle with spin 1/2. A component of mundane terrestrial matter, and part of all neutral atoms and molecules. It has a mass about 1/1800 that of a proton. Its antiparticle is the positron.
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1answer
50 views
What determines the charge of an electron? [on hold]
So I am thinking of making a machine that turns electrons into positrons.
So you put as many electrons as you want in one side and positrons come out the other side. This will solve all out energy ...
-6
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1answer
61 views
Why an electron “rotate” around the nucleus at a speed close to the light one? [closed]
Why an electron "rotate" around the nucleus at a speed close to the light one?
I mean where he gets all this energy?
One DOES NOT simply approach the speed of light AFAIK.
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3answers
64 views
Photoelectric effect: according to classical physics?
This is a sample test question I've encountered twice in some practice chemistry finals. I'm a little bit confused about what it's asking.
You are conducting an experiment on the photoelectric ...
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1answer
20 views
The Observance of Electromagnetic Phenomena
As far as I've seen, E&M waves are sinusoidal. Our eyes observe these patterns and give us colors, but in a situation like such: Why do electrons emit radiation?
There is still a wave, or at least ...
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1answer
85 views
How to know electron and muon neutrinos are different except measuring mass
Before the discovery of neutrino mass, how did people aware electron and muon neutrinos are different?
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2answers
113 views
Do electrons have a radius when they behave like a particle?
I know sometimes electrons behave like waves, but it sometimes can be seen as a particle. while it's a particle, does it have a radius? or, a volume? If it doesn't even have a volume, how can we still ...
3
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2answers
125 views
Why do electrons emit radiation?
I know how you can emit light with an alternating current, running back and forth, creating an electric field in addition to the magnetic field.
But why does an electron emit light when it gets ...
2
votes
2answers
76 views
Electron revolving in an atom
When an electron revolves around the nucleus in P or d-orbitals why does not it collide with the nucleus.
I mean to say that the shape of the orbital narrows near the nucleus , so shouldn't it collide ...
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0answers
30 views
What is the secondary electron cutoff in ultraviolet photoelectron spectroscopy?
While the fasted emitted electrons comes from the fermi level of the material in UPS measurement, where does the slowest, which is called secondary electron cut-off orginate from? I really can't ...
3
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1answer
59 views
How can we describe the electrons of multi-electron atoms (i.e. not Hydrogen) when equations/analytic solutions only exist for Hydrogen?
I've been digging into emission spectra of different elements and found that such things as the Rydberg equation, Bohr's model, and quantum mechanics can only fully describe the single electron in the ...
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2answers
124 views
Are Electrons Electromagnetic Waves?
I encountered a thought provoking article suggesting that electrons are electromagnetic waves. Is this possible? I may not agree with their entire model, but surely there is the possibility that an ...
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3answers
99 views
How Does $\epsilon$ Relate to the Dampened Harmonic Motion of Electrons?
I realize that the permittivity $\epsilon$ of a substance is easily calculated based on diffraction angles, but I am not satisfied with merely measuring it experimentally. I wish to understand its ...
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1answer
53 views
Electric fields problem [closed]
Why is this the case..
I would have thought it would have followed the E field?
7
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1answer
214 views
Who (and Why) started the “electrons are negative, protons are positive” convention? [duplicate]
For some reason everyone labels electrons using a minus sign and protons using a positive sign, even though the opposite seems more intuitive:
Who started the convention that electrons should be ...
0
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0answers
39 views
Why aren't there more than three generations of the leptons and quarks? [duplicate]
There are three generations of electrons, neutrinos, and quarks. The second and third generations of electrons and quarks are unstable and decay into lighter particles.
Why are there exactly three ...
2
votes
2answers
58 views
Why are there two quasi Fermi levels and only one Equilibrium Fermi level?
I am reading a book and I'm trying to understand the concept of quasi Fermi levels.
For example,
A steady state of Electron Hole pairs are created at the rate of $10^{13}\ \mathrm{cm}^{-3}$ per ...
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1answer
27 views
Dirac electron polarity?
according to
Spin of an electron
Dirac said the electron has Two possible spins if i'm correct.
Do Electrons have polarity? measurable by its Dirac spin or probabilistically by its quantum states?
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0answers
21 views
Secondary electron gain vs. secondary electron yield
The context of the question is an electron microscope.
Can someone explain me the difference between secondary electron gain and secondary electron yield?
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1answer
56 views
How is the energy of an electron-shell related to the speed of electrons in that shell?
I am trying to gain an intuitive picture of what is referred to by "electron-shell energy". I have read that outer electron shells have higher energy than inner electron shells, and this seemed to ...
0
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0answers
22 views
Interaction of SEM electron beam with material
When an electron incident on a material what is the interaction
between electron and material?
The question is about SEM (Scanning electron microscope).
So, the electrons beam will interact ...
0
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2answers
64 views
Do excited electrons drop back to same quantum state?
I'm trying to wrap my head around spectroscopy, therefore, I am looking for as complete an answer as possible here, hence why I have broken the question into a different points.
Here is what I know ...
1
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2answers
84 views
Collision between a photon and an electron
Looking through this AP Physics question, I was struck by how the 'collision' between a photon and electron looks so much like a macroscopic collision. Is this even physically possible?
Look at the ...
1
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0answers
27 views
Single electron pumps, superconducting energy gap
I am seeking to find out how many electrons per gate cycle are pumped at different temperatures. The Single Electron Pump is made out of Al, with a $T_c=1.2\,\mathrm{K}$. This single electron pump is ...
1
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2answers
89 views
Currents and the Speed of Light
Why is it that currents don't flow at the speed of light, but rather significant ratios of the speed of light.
I don't have any formal reasoning as to why they would flow at the speed of light-I just ...
11
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2answers
236 views
What happens in electron-electron collisions?
What are the results of high energy electron electron collisions? Are other particles created?
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0answers
50 views
Is this picture of the electron dipole moment correct?
It's the electron spinning on its axis, and a magnetic moment shoots up. The direction of the North-South is opposite what I thought it should be. Why is the vector arrow pointing from North to ...
5
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1answer
86 views
Do electrons need specific energies to excite electrons
Photons need specific energy levels, equal to the difference between two energy levels to excite an electron in an atom. Is this the same case with electrons that collide with atoms?
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1answer
44 views
Why doesn't intensity of light affect the emission of electrons?
So electrons of specific atoms have a minimum amount of energy needed to escape the atom, called the work function, W. Now let's say that you emit a certain frequency of light, and $hf<W$. However, ...
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1answer
78 views
Distinguish electron-like and hole-like orbits in reciprocal space, with reference to the Brillouin Zones
So I have a solid state and thermodynamic exam next week and I've been going through some of the previous exams from years gone by to prepare. I came across this question "Distinguish electron-like ...
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2answers
40 views
A question on lewis model [closed]
Electron affinity of chlorine = -349 kJ per mole. And, first ionization energy of sodium = 496 kJ per mole while energy required for combining= 147 kJ per mole.
Isn't it a contradiction against ...
3
votes
1answer
102 views
What is the math showing that the time reversed version of an electron is a positron? (+general time reversal question)
As in Wheeler's One Electron Universe idea, how do you show that electrons and positrons are time-reversed versions of each other? Do you just apply time reversal to an electron and out pops a ...
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2answers
313 views
Definition of electric charge and proper explanation
Is there a definition of electric charge and proper explanation of it?
It is said "Electric charge is the physical property of matter that causes it to experience a force when close to other ...
-1
votes
1answer
30 views
Charge gained due to photoelectric effect [closed]
Here I think, one beam will knock out just one electron. So, I am not able to even understand what the question says. Please someone give a hint as to what the question asks...
As source of the ...
0
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1answer
70 views
Difference between atom and elementary particle questioned
Hydrogen ion doesn't have one electron which clearly mean that it has only one proton..So hydrogen ion is only a proton. Am I right, please make it clear. If hydrogen ion and proton are same that how ...
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0answers
27 views
Ballistic Conduction - Difference between Bosonic and Fermionic Transport
Ballistic Conduction is the phenomenon of an ideal conduction environment for quantum particles - for electrons the Ballistic Conduction is not infinity, but is proportional to the difference between ...
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3answers
161 views
Why do people claim electrons are accelerating
A lot of text books mention that one of the reasons that classical mechanics failed to explain atomic and subatomic processes is that electrons which accelerate should release energy in the form of ...
3
votes
2answers
106 views
Transfer of electron energy to atoms (heating up of matter by absorption of photons)
If an electron absorbs a photon to get exited to a higher energy level, it should either come back to same state or any other lower state by emitting the required photon. How then can there be a net ...
1
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1answer
66 views
Understanding drift velocities in currents
I have a doubt about the understanding of drift velocities in a current. My problem is that the textbook speaks very loosely about this. It's like: "well, if we apply a field $E$ then the charges will ...
1
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1answer
71 views
Joule heating due to the (slow) electron drift velocity?
I understand the concept of why the signal speed is higher than the electron drift velocity, but I can't understand the concept of joule heating. If electrons move slow then how do they produce a lot ...
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3answers
138 views
Why doesn't a stationary electron lose energy by radiating electric field (as per coulomb's law)?
If an electron in a universe constantly generates an electric field why does it not get annihilated ? I am confused because I read that an accelerating charge radiates and loses energy. So, why won't ...
3
votes
2answers
168 views
Why the K shell only contains 2 electrons?
It is written in my quantum physics book that the K shell contains only 2 electrons due to the Pauli principle.
I know that if $n = 1, l = 0, m = 0$, then the Hilbert space associated to the spin is ...
-2
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1answer
84 views
Is speed of electrons in atoms a constant during explosions? [closed]
E.g. in exploding nuclear bomb or some other big explosions.
I mean if the speed of electrons as waves/particles is a constant or changes according to other "forces" involved?
3
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0answers
38 views
Is it reasonable to interpret the Lamb shift as vacuum induced Stark shifts?
This is a pretty hand-wavy question about interpretation of the Lamb shift. I understand that one can calculate the Lamb shift diagrammatically to get an accurate result, but there exist ...
3
votes
2answers
95 views
Regarding the free electrons on the conductor
In a metal, why don’t the free electrons fall to the bottom of the metal due to gravity?
Also, charges in a conductor are supposed to reside on the surface so why don’t the free electrons all go to ...
2
votes
3answers
286 views
If photons can be absorbed by electrons, wouldn't that mean light has a charge? [duplicate]
I am a biochemistry and molecular biology major. If photons can be absorbed by electrons, wouldn't that mean light has a charge? Electrons only attract positive charges. Isn't it?
3
votes
1answer
55 views
Planes of graphite crystal on diffraction experiments
When doing electron diffraction on graphite (a popular experiment for students at universities) always diffraction at these two planes with distances $d_1$ and $d_2$ are observed:
But a plane ...
3
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1answer
45 views
Electron Spin Resonance and Free electrons
When performing an experiment to observe electron spin resonance, we use DPPH molecules as they contain an unpaired electron on one of the N atoms.
My question is, why cant free electrons be used in ...
1
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1answer
78 views
B-field and Magnetic forces, speed of a particle
Let's say I have a particle moving perpendicular to a uniform magnetic field of magnitude $x \ T$, and it moves in circle with a fixed radius. How do I find the speed of this electron? Initially I ...
0
votes
1answer
250 views
How electrons act under rotating magnetic field?
I study Power Engineering in University. Today I asked my lecturer to explain me exactly how atom's electrons act under spinning rotor's magnetic field, that generated dynamic electricity. But he even ...
4
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2answers
213 views
Do protons exchange photons with electrons?
I'm sorry for this question but, I just don't get it. According to the electromagnetic field theory, electrons repel each other by exchanging photons. How do protons attract electrons, by photon ...
