# All Questions

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### Particle displacement at a rarefaction or compression

In a longitudinal wave, why is there zero particle displacement at a compression or rarefaction and maximum displacement at a point pi/2 from it? Shouldn't it be the other way round?
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254 views

### What makes nuclear binding energy so much stronger than chemical energy

The strong force acting between quarks and responsible for holding protons together is 100 times stronger than the electromagnetic force. How come the nuclear binding energy derived from the strong ...
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12k views

### Why can't a gas be liquified by pressure above its critical temperature?

What is the cause behind a gas being difficult to liquify above its critical temperature no matter how much pressure is applied on it?
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### Different cross section for W and Z boson

At hadron colliders the cross section for W production is about ten times larger than the production cross section for Z bosons (e.g. Figure 2 in this review article). I guess the dominant ...
107 views

### Where did the universe get its initial momentum?

If, according to Newton's third law, forces come in pairs then what about the big bang? where did the universe get that initial push/momentum?
102 views

### Why is a Electron negative not both?

I was pondering on the question of magnetic dipoles but then I had an thought that electron and other particles are either positive or negative or have no magnetic charge but then I thought of ...
76 views

### Can the new results (about photonic time travel) make quantum computers feasible?

New results published about photonic time travel, reference here make quantum computers a reality in the near future? These results seem to indicate that there can be qubits that can exhibit nonlinear ...
591 views

### Does the Bohr van Leeuwen Theorem also apply to ferromagnetism?

I know that the Bohr-van Leeuwen theorem shows that there could be not consistent pure classical explanation of dia- and paramagnetism. Does the same theorem also rule out a consistent classical ...
507 views

### Why is the intensity of Hawking radiation dependent on the size of the black hole it comes from?

I am asking for a non mathematical answer. I think I have a pretty good understanding of physics without the maths, which unfortunately eludes my understanding. It may be the answer would be obvious ...
3k views

### Does a man on the moon experience day?

Does a man on the moon (or any other similar body) experience daytime like we do? By daytime I mean looking upward and seeing a bright "sky," not dark space. If not, then what is the reason behind it?...
447 views

### Is there a reaction force on the ball in a vertical circular motion?

You have a light string. At one end of the string there is a ball modelled as a particle. The string has negligible mass. The other end of the string is fixed at a point and the ball is undergoing ...
235 views

### What is a graviton?

We know that a graviton is a hypothetical particle that carries gravitational energy. I have no definite knowledge in string theory, being a student; taking classical gravity into consideration or ...
141 views

### CPT symmetries for a free Klein-Gordon equation and in minimal coupling

I'm studying for an exam on relativistic quantum mechanics and one of the issues to prepare is about symmetries of Klein-Gordon equation concerning $C$, $P$, $T$ transformations for a free field, and ...
694 views

### Difference in decay for muon and anti muon

In a couple weeks, I will conduct a lab experiment where I measure the lifetime of the muons from the secondary cosmic radiation. For that, we have two detectors above each other, one will give a ...
2k views