All Questions
Tagged with electromagnetism nuclear-physics
75
questions
15
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2
answers
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Why do spin-$\frac{1}{2}$ nuclei have zero electric quadrupole moment?
Why do spin-$\frac{1}{2}$ nuclei have zero electric quadrupole moment? How does this come about, and how can one tell in general whether a spin-$j$ nucleus can have a nonzero quadrupole (or higher ...
- 3,701
4
votes
2
answers
7k
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What makes a nucleus unstable?
My question is simply that - what makes a nucleus unstable? What exactly causes a nucleus to start breaking apart in the first place? Is it the Coulomb force between the neighboring protons?
I'm just ...
- 5,371
5
votes
7
answers
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Why can't electrons fall into the nucleus? [duplicate]
I read a book on pop sci book on quantum mechanics and the author said that electrons do not fall into the nucleus due to quantum mechanics- which principles suggest this (I think it was Heisenberg's ...
- 457
4
votes
1
answer
2k
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Why are atomic quadrupole moments calculated using nuclear spin?
It's my understanding that electric quadrupoles interact with the gradient of an electric field, and I understand roughly how this works. I am trying to calculate the interaction between an atomic ...
- 373
5
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3
answers
5k
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What causes radioactivity? Is it a quantum mechanical effect?
I'm just curious what causes radioactivity. I've been told that in the case of alpha decay, since the nucleus is quantum mechanical, there is a probability that the configuration of protons and ...
- 229
2
votes
2
answers
162
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Copper coils for nMRI
Given the lack of financial efficacy in the medical industry, I was wondering if nuclear magnetic resonance imaging would be possible with a copper/silver coil if the use is short 10 second imaging ...
2
votes
1
answer
231
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Angular momenta of photon
$A^\mu$ can have multipole expansions in classical electrodynamics. This gives rise to dipole photon, quadrupole photon etc. For dipole photon $j=1$ (In electrodynamics books they write it as $l=1$). ...
- 26.8k
5
votes
1
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What prevents an atom's electrons from "collapsing" onto its protons? [duplicate]
Forgive me if the answer to this is obvious. I have no formal physics training, and I remember that when I asked my physics teacher this, she just frowned and said "Good question."
An electron is ...
- 251
3
votes
1
answer
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Why isn't Hydrogen's electron pulled into the nucleus? [duplicate]
Possible Duplicate:
Why do electrons occupy the space around nuclei, and not collide with them?
Why don’t electrons crash into the nuclei they “orbit”?
From what I learned in chemistry, the ...
- 335
1
vote
1
answer
2k
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How positively charged protons remain glued to each other while they should repel each other out of nucleus? [duplicate]
Possible Duplicate:
Protons' repulsion within a nucleus
How positively charged protons remain glued to each other while they should repel each other out of nucleus?
- 11
9
votes
2
answers
8k
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We know that the protons in a nucleus are positively charged. So why does the nucleus stay intact? [duplicate]
We know that the protons in a nucleus are positively charged, whereas the neutrons do not possess a charge; we also know that unlike charges attract. So why does the nucleus stay intact, even though ...
- 833
15
votes
4
answers
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Do neutron stars reflect light?
The setup is very simple: you have a regular ($1.35$ to $2$ solar masses) evolved neutron star, and you shine plane electromagnetic waves on it with given $\lambda$. Very roughly, what shall be the ...
- 2,374
16
votes
4
answers
16k
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Protons' repulsion within a nucleus
Do the protons inside the nucleus repel each other by the electrostatic force? If they do, why doesn't the repulsion drive the protons apart so that the nuclei get disintegrated?
- 273
3
votes
1
answer
379
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PNMR, Pulsed Nuclear Magnetic Resonance, Experiment
I am writing a lab report for class on PNMR experiment that we did. How come in this experiment we don't worry about the electron spins in our sample? Aren't the electrons affected by the PNMR machine ...
- 3,871
2
votes
1
answer
823
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Cherenkov radiation in nuclear bomb
Would Cherenkov radiation occur at the explosion of a nuclear bomb? Suppose it would not be occluded by smoke or anything else for that matter.
- 250