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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Energy and momentum of a relativistic electron

The question is to find the magnitude, $p$ of the electron's momentum in the unit of MeV/$c$, given that the kinetic energy of the electron is 2.53 MeV. The answer provided by the book says, ...
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31 views

Why Electron Does Not Radiate In Bohr Orbits? [duplicate]

Maxwell said that charged particles radiate when are in accelarating motion. I understand that $nλ=2πr$ must be fulfilled in order to create a sinusoidal standing wave and to satisfy the probability ...
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48 views

Does a free electron, one that's not either in an atom or a wire, have an associated wave-function?

Would a free electron, one that's not either in an atom or moving through a wire, but moving through empty space on its own, have an associated wave-function? Or, is an electron described as a ...
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36 views

How many different ways of generating electromagnetic radiation you know? [on hold]

I am interested in a list that also takes into account the causes at the atomic level. For example, radio waves from antennas are a periodic electromagnetic radiation. At the atomic level, the cause ...
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6 views

Number of Atoms in a State with a Constant Time T with Decay

A state of energy E1 with a lifetime of T1 decays into the state of energy E2. The state of E2 then decays with a lifetime of T2 into the state of E3. It is known T1 = 2T2. Initially all of the atoms ...
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Relationship between Fermi Energy and Average Energy

Electrons are in a one dimensional box of length 2L. What is the relationship between Ef, the fermi energy and E, the average energy? The answer is Ef/3 I looked up the formula for the relationship: ...
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51 views

How long does it take for an excited electron to return to ground state?

During a mock Cambridge interview, one of the questions was about how small a computer could theoretically be.The way I approached it was in terms of what something must be to be considered a ...
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22 views

Collision between electrons & nucleus [duplicate]

I am new with physics and I have a confusion that since electron and nucleus has opposite charges then why they do not collide with each other inside an atom?
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2answers
60 views

Resonate frequency of an object?

Below is a paragraph taken from the web site, physicsclassroom.com: It is often useful to think of these electrons as being attached to the atoms by springs. The electrons and their attached ...
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26 views

What is the frequency associated to the orbitals within an atom?

I was told that there's a vibrational frequency associated to the orbitals within an atoms, but it is a frequency related not to a classical vibration. What Hz frequencies would these be?
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18 views

Is $\kappa_e$ caused by charge-carrier transport or electron transport?

$\kappa$ usually symbolises thermal conductivity, a material's ability to conduct heat. $\kappa$ can be expressed with other partial thermal conductivities: $\kappa=\kappa_e+\kappa_{ph}+...$ where ...
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14 views

What is the equation to calculate the strength and radius of an electromagnetic pulse?

With this interesting answer on the blast force of a uniformly charged electron sphere, came another interesting question. What would be the strength and blast radius of an EMP launched from such a ...
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28 views

Why did scientists use a zinc-sulfide coated screen to detect the alpha, beta, and gamma radiation?

How does a zinc-sulfide coated screen work, and how does it manage to detect high-frequency radiation, electrons, and helium? Could it be possible that a delta ray managed to somehow slip past ...
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42 views

What do moles and moles of various subatomic particles gathered together look like?

I wonder whether it is even possible to find the answer. If it is impossible to find out, why? Do moles of neutrons basically look like a neutron star? If so, what does one look like? How about ...
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67 views

Can electrons reflect light?

Lately, I have been watching sparks while connecting my electronic devices and I can notice that electricity is kind of blue, and theoretically it's blue because it reflects blue wavelengths?? And ...
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36 views

What is the frequency of each of the moving electrons in a DC current?

I know that the DC current has 0 frequency. But what about each individual moving electron that makes up that DC current? Of course there has to be a frequency as all moving electrons are vibrating at ...
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21 views

How does a high voltage produce ions

I was reading about gas discharge tubes and it said that when a high voltage is applied between the cathode and anode, electrons get pulled off the gas atoms. My question is how does this happen ...
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12 views

Electrons in a gas discharge tube

I'm having some difficulty understanding regarding electrons in gas discharge tubes. My understanding is the following: In a gas discharge tube the gas must be at low pressure in order to be ...
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24 views

Do electrons move easier depending on the way a TIG tungsten head is grinded?

I'm in a TIG welding course, and during the course we (inevitably) messed up a few (suicidal) tungsten heads by grazing/suicide dive into the molten puddle during operation. Standard procedure is to ...
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43 views

Explanation of van der Waals force

Can someone please explain why the van der Waals force is attractive instead of repulsive? My understanding is that is has to do with the electron cloud creating a dipole, but I can't seem to ...
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19 views

Spherical Aberration Of Electron Lenses

I would like to know why electron lenses can't have negative spherical aberration. Every textbook I have found devotes one or two sentences to saying that Otto Scherzer prooved this 80 years ago, but ...
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1answer
59 views

How much space does an atom occupy? [closed]

So my stupid question is: we know that in the classical model of a atom there is a nucleus at the middle and electron revolving around it in orbits numbered from 0 to infinity. So according to this an ...
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1answer
36 views

How does Kohn's theorem demonstrate that a rotating microwave field can only connect the ground state with the cyclotron mode?

This is a follow-up question to Proof of Kohn's theorem. I am confused about a point in the answer given by @NowIGetToLearnWhatAHeadIs. It is noted that the perturbing Hamiltonian in Equation 12 ...
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57 views

How long do electrons take to “decide” how to go through a circuit?

Many other people have asked how an electron decides which path to take, but no one has asked how long do they take. Is there an equation for their "uncertainty" time? Do they decide instantaneously ...
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115 views

What will happen when lightning strikes on the surface of the deep sea?

The lightning is having enormous amount of energy, as it strikes the ground it makes various electrical and magnetic effects. If the lightning strikes a tree, that will be burst by lightning. ...
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490 views

Why does the electron volt seem inconsistent with mass?

If I understand correctly, an electron volt is the work done when an electron is moved from a plate with a voltage of 0V to another plate with a voltage of +1V. This is represented by $V = W/Q$, or $W ...
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58 views

What is the cause of the time-varying electric and magnetic near-fields around a wire with a 60Hz AC current?

I know that it's the accelerating electrons in an AC current that are the cause of far field effects. But, what about the reactive near field close to a wire that has a 60Hz AC current? What is the ...
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How does electricity produce magnetisim?

I am in class 10 and I have just read the electromagnetism chapter. They always keep on saying that electricity produces magnetism! but how!? We know electrons move, but how do they produce something ...
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72 views

Photoelectric effect – Why does one electron absorb one photon?

When I read about the photoelectric effect, I came across this: "The electrons could not absorb more than one photon to escape from the surface, they could not therefore absorb one quanta and then ...
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43 views

Why don't electron microscopes use huge detectors?

Electron microscopes have limited resolution. I have read experts saying that we need better electron detectors to get better resolution. Why can't we just use bigger detectors? Increase the ...
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1answer
56 views

Is there experimental evidence for the model of discrete intervals and orbital distances for electrons around the atomic nucleus?

Is there strong supporting evidence of discrete electron shells or orbitals surrounding atomic nuclei? I realize the math works out and we have energy frequencies emitted, perhaps even atomic ...
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26 views

Derivation of diffusion coefficient

For diffusion transport considering the "random walk" of electrons, I have the following derivation that leads to the diffusion coefficient $D$: $$d_1=d_2=\dots=d_n=\tau v \implies\\ \sum_n ...
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42 views

Exploiting Resonance to Make a Bound State with Gamma Rays (and other Very High Energy Particles)

One obvious consequence of any finite potential is that a high enough energy wave-function will not form a bound state, either they are high enough energy they will generally just bypass the barrier ...
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63 views

Basic concepts on Electricity [closed]

How do electrons move? I mean really do they move? I read that they move in circular shells AROUND THE NUCLEUS. How can they move in the conductor? I have read that there are valent electrons that ...
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1answer
59 views

What actually happens when electrons 'collide' with other electrons in a conductor to produce heat in an electrical circuit?

Textbooks describe resistance as involving electrons colliding with other ions in metals, resulting in a heating effect, though how exactly is this achieved? Although I am not required to learn the ...
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Binding energy per nucleon dependency

For a given isotope, does the nuclear binding energy per nucleon depend on the presence of electrons? For instance, if an electron was excited by an incoming photon and jumps to a different orbital, ...
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2answers
45 views

Radioactivity, alpha decay [duplicate]

In alpha decay, a $\text{He}$ nucleus is emited along with a daughter nuclide. Now suppose $\text{U}$ with atomic number 92 and atomic mass 238 emits an alpha particle and a daughter nuclide is formed ...
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112 views

Can two electrons attract each other?

Due to electrostatic repulsion the two electrons will repel each other as they both possess similar charges, lets leave gravitational attractive force out of the picture my question is can there be ...
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3answers
51 views

Can we have electronics with charge carriers OTHER than electrons?

Ions perhaps? Or other elementary particles with charge?
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3answers
101 views

Do holes have physical existence?

We know that holes are created due to electrons hopping from one covalent bond to another. But does a hole have a physical existence or it's just a fictitious positive charge, an illusion created by ...
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1answer
53 views

Why and how do electrons move so much? [closed]

Why do Electrons move so fast and why. I already tried the physics classroom but I can't seem to find the right answer .
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1answer
45 views

How to create a vaccum tube & produce electron beam

I know that when an anode & cathode are placed inside a vaccum tube, electrons are emmited from cathode and goes towards anode. So, How to produce such a high voltage?, How to create such a ...
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1answer
65 views

Modified double-slit experiment - two electron sources instead of two slits

In the famous double-slit experiment, if I inserted two identical sources (i.e electron guns) at the locations of the slits, would I still see an interference pattern on the screen? I would allow ...
3
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1answer
108 views

does a resistor slow down the flow of electrons or just let less electrons through? or is it both?

I like to have an intuitive grasp of whats happening our tutor said they 'resist' the flow of electrons but I want to understand exactly whats happening.
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42 views

is speed of light is the limit [closed]

If an electron is away from a proton about 1 kilometer and the proton is fixed what will be the velocity of electron when they collide? I calculated it its speed was coming out to be more than the ...
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2answers
64 views

Do rainbow shows spectral lines?

A spectral line is the electromagnetic radiation emitted when the electron jumps from higher orbital to a lower orbital of an atom. Water mainly consists of two elements namely hydrogen and oxygen, ...
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1answer
66 views

Can Maxwell's Equations explain electromagnetic radiation emission in an atom?

Can Maxwell's equations be used to explain the process of spontaneous emission when an electron drops from a higher energy level to a lower energy level? According the Maxwell equations, a changing ...
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3answers
342 views

How does the number of electrons and protons determine the melting point and hardness of a solid?

How does the number of electrons, neutrons and protons determine the melting point and hardness of a solid/metal? And is it possible to create custom elements which is very strong and have very high ...
2
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3answers
119 views

Electric field or static electric field around a plugged-in lamp cord (when lamp is not turned on)?

When an electrical cord from, say, a lamp, is plugged into an AC wall socket, I'm aware that an electric field forms around the entire length of the cord and even before the lamp switch is flipped on. ...
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1answer
55 views

What is the amount of charge density in a metal wire for the electron's which are involved in current flow?

According to the question Why is charge = nALe n is the charge density (number of electrons per unit volume). Which of the electrons in a metal wire are involved in current flow? Only the unbounded to ...