# electrons's questions - Chinese 1answer

1.749 electrons questions.

### Why electron energy increases in an excited state?

2 answers, 18 views energy electrons
After absorbing a photon with the minimum threshold frequency an electron gains energy and enters an excited state, but according to Couloumb's law a greater distance between two charges will result ...

### 2 Spin of electron [duplicate]

While reading 'The Universe in a Nutshell' by Stephen Hawking, I came across the example of cards and how he used it to explain concept of spin and fermions and bosons. There he defined 'Spin' as ...

### 2 Is a charged particle in motion an electric current?

Do a moving charge let's say electron linearly with constant velocity constitue an electric current? If yes what would be it's magnitude?

### 3 Opacity/transparency of conductive meshes to charged particles (electrons/ions)

When using a conductive (metal) mesh, effectively a metallic woven fabric, in vacuum applications as a "grid" for charged particle optics, how does one calculate (or at least estimate) the opacity or ...

### In the Bohr model, how do you derive that the angular momentum of an electron in a stationary state is a quantized integral value of $h/2\pi$?

I understand that Bohr postulated that electrons can only occupy orbits at certain radii, and that in order to move from one orbit (or stationary state) to another, it would have to absorb or emit a ...

### Why not free electrons in atom doesn't radiates em waves\photons?

Why not free electrons in atom doesn't radiates em waves\photons, although they move with acceleration? Like 1s electron of Titan, it doesn't emits em waves, yes? Why?

### 1 Flow of charges in two different materials

Consider two cylindrical conductor rods: one copper rod and one aluminium rod. The rods contact at a circular face, aligned coaxially. Their exterior circular faces are connected to some DC voltage. ...

### electric dipole spin resonance and anomalous coordinate

On the wikipedia page about electric dipole spin resonance (EDSR), they define what they call 'the anomalous coordinate,' which is $\textbf{r}_{so} \approx \frac{\hbar^2 |g|k}{m_0 E_G}$. Apparently, ...

### 4 Feynman and Perpetual Electron

In the paragraph 1–2 "Matter is made of atoms" of the first Volume of his lectures, the great Feynman says that electrons are in a perpetual motion. Now, i'm new to physics and i don't know quantum ...

### 1 What produces higher frequency light?

I don't know much more than the basics of the theory, so if my question stops making sense at some point, an answer addressing that would be awesome. From what I understand so far, photon creation ...

### 1 De Broglie Wavelength interpretation

I've just started learning about the double slit experiment (just in the short appendix section in Schroeder's Thermal Physics), and I'm extremely confused by this one thing: In it, out of basically ...

### -1 Would the double slit experiment still yield the same results if the electron were travelling really slowly?

And I mean really slow. I don't know how this would even be done, but just a thought experiment. To explain why I ask this, the way I understand the phrase "we can't know the momentum and position ...

### -1 Can Tungsten (W) be used to Shield from EMR? [on hold]

0 answers, 19 views electromagnetism electrons
Please adise if possible. Thanks. Im designing a tungsten coated business card to help shield against EMR from cell towers. If I electro charge it (on a wireless phone charger) will the tungsten ...

### 1 How do quarks interact with the Higgs field?

I know that electrons' only interaction with the higgs field is due to ambidextrousness and the weak hypercharge which is provided by the higgs boson, but how do quarks (specifically up and down) ...

### Electric fields and insulators

Will the electric field of an induced dipole in an insulator match the electric field inducing it but in the opposite direction? I have 2 counter theories: Let's say I place an insulator (and let's ...

### 1 Why is the drift velocity directly proportional to the electric field?

If I double the electric field, that should double the acceleration of electrons inside the conductor in the general direction of the electric field. But why does that double the drift velocity, and ...

### How would we calculate the magnitude of the electric field of a battery? [closed]

For a battery with a given voltage, how would we calculate the electric field? Thanks!

### Interpretation of Rutherfords gold foil experiment with electrons

0 answers, 179 views electrons atomic-physics
When Geiger and Marsden shot alpha particles at their metal foils, they noticed only a tiny fraction of the alpha particles were deflected by more than 90°. Most just flew straight through the foil. ...

### 6 How does an electron “move” in an $s$-orbital?

I have read multiple answers on StackExchange about this question, but I wasn't able to find a concrete answer. Like other questions, the reason I ask about the $s$-orbital is because it has a zero ...

### 14 At an atomic level, what happens when you connect two batteries in series so that their voltages are added?

I can't for the life of me figure this out. I feel like i'm missing some crucial detail about how batteries work. Imagine two batteries connected in series, like this: ...

### 4 How do surfaces give out sound by friction, when its said that bodies dont actually touch?

2 answers, 42 views electrons acoustics friction
So due to electron-electron repulsion, isnt it true that surfaces dont really 'touch'? If so, then how do two things rubbing each other give out sound due to friction? or is that because the uneven ...

### Cathode rays magnetic field [duplicate]

0 answers, 12 views electromagnetism electrons
My question is regarding the fact that magnetic field is generated only by moving charge and it can act only on charged moving particles. So if we have two cathode rays one, by the other and its ...

### In a photovoltaic effect, when the electron absorbes the photon, is the electron's energy displaced?

2 answers, 246 views photons electrons photovoltaics
I'm a super amateur wannabe physicist, and I'm trying to learn the fundamental workings of the photovoltaic effect. I haven't been able to understand "how" or "what" is displaced/transmitted in the ...

### Can atoms capture beta particles or secondary electrons into their orbits and become anions?

Since beta-particles are just free-moving electrons, shouldn't they be caught by strongly-electronegative atoms and thus create anions? Why do they instead create more cations by knocking other ...

### 2 The energy stored in the electromagnetic field of an electron

Due to Wikipedia the total energy per unit volume stored in an electromagnetic field is $$u_{EM}=\frac{\varepsilon}{2}|\mathbb E|^2+\frac{1}{2\mu}|\mathbb B|^2$$ How does the energy stored in the ...

### estimating number of electrons available for conduction [closed]

I've been asked to estimate the number of electrons in a metal, and the number of electrons available for conduction. I don't want to use proper Fermi-Dirac or anything, I just want an easy way to ...

### Is the electric field in the wires of the parallel circuit always the same and how that affects current?

When we connect two resistors connected in parallel with a battery, it creates an electric field through this wire. well, my question here: Is the electric field in the main wire is the same as the ...

### Newbie question: Atom identity. How can you talk about two electrons if electrons are identical? [closed]

How can you talk about two electrons if they are identical (indistinguible)? Does it make sense to let an electron to have an identity by itself? If they are on diferent places the place they are is ...

### Can someone give a simple mathematical explanation of the tight binding method?

I'm trying to understand the tight binding method but I'm struggling with a lot of the mathematical formalism. A lot of the mathematical formalism I read jumps into explaining it a few too many steps ...

### Endless electron-positron annihilation/creation?

We start the process with gamma rays collision that produces positron electron pair, the pair then annihilates when hit each other and gamma rays are produced again and everything repeats. Sure, in ...

### 1 Even/odd number of electrons per primitive cell and conductivity

1 answers, 29 views electrons crystals metals
In this pdf it says Because the number of electron states in a Brillouin zone is twice the number of primitive cells in a Bravais lattice (the factor two comes from spin), the zone can be ...

### Why there is no charge within the conductor even if the charges are static?

"When excess charge is placed on a solid conductor and is at rest, it resides entirely on the surface, not in the interior of the material. �" Source: University physics 13th edition p(736). ...

### Is the right-handed electron really an $SU(2)$ singlet?

In the Standard Model, neutrinos are assumed to be massless, and the right-handed neutrinos thus do not exit. Is this the reason that the right-handed electron is regarded as an $SU(2)$ singlet? ...

### 2 Does an electron have a frequency (and hence an energy)?

0 answers, 36 views energy electrons fermions dispersion
The formulation is provocative, the question is similar to the question here. There I can follow the question, but not the answers, which for me imply that an electron in a momentum eigenstate does ...

### 1 Quantum tunneling versus over-the-barrier ionization

I was doing a quantum physics past paper and there was this question about ionizing atoms with laser. My answers made reference to the photons within the laser knocking off or transferring their ...

### 1 Speed of electron and proton in electric field

Speed of electron and proton in electric field. In a uniform electric field E, the acceleration of an electron in vacuum is 1836 times that of a proton (proton/electron mass ratio is 1836). I'll like ...

### 3 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 ...

### Is it possible to calculate the energy level of a ground state of an electron?

All throughout my homework the lowest electron level (ground state) is never referred to as a number. Is it possible to calculate it numerically? I have wondered this because a question asked "what ...

### 7 What keeps electrons in an atom from flying away or falling into the nucleus?

In atoms, what force or charge, etc. keeps electrons from flying away or into their nucleus? is there a kind of weak-force at work on the atomic scale? Note I am aware the electron positions are ...

### -1 If electricity is made up of electrons, how can it cause the hydrogen spectrum to appear?

The hydrogen spectrum appears when an electron absorbs a photon, jumps an orbital, and then releases that photon in an effort to get back to its ground state. From what I've read electricity is ...

### 3 Why do thermal hotspots in a metallic nanoparticle do not match it's optical hotspots?

I am a little bit confused here. When a metallic nanoparticle is impinged with light at its resonance, the electric field is greatly enhanced at the surface along the polarisation of the wave(suppose ...

Here, under the subtitle 'principle,' it describes what happens when you have a static magnetic field along the z axis, $B_0 \hat{z}$ and microwave field parallel to the $x$ axis, $B_1 \hat{x}$. I ...

### Can we create a electric field without actually using a battery or power source?

Can we create an electric field without actually using a battery or a source of electricity? Like a take 2 panels, one is positively charged and another is negatively charged and put them parallel to ...

### Perovskite solar cells: Why are electron/hole-transporting layers required?

I am looking at device architecture of planar heterojunction solar cell. What I understand from reading "Planar heterojunction organometal halide perovskite solar cells: roles of interfacial layers" (...

### Can charge move without accelerating?

According to Wikipedia : "An electric potential (also called the electric field potential, potential drop or the electrostatic potential) is the amount of work needed to move a unit positive charge ...