B Photon Emission: Classical vs Nuclear Fusion

[sadaronjiggasha]

In classical physics we know photon emits when electron move from higher to lower state but in nuclear fusion photon emits when neutron turn into proton. Is both correct?

 

[PeroK]

This is the sort of queston where we encourage you to find reputable material and to ask specific questions about that material. It's much better for everyone if you ask questions relating to, in this case, a specific source explaining the nuclear fusion you are asking about.

 

[topsquark]

In classical physics we know photon emits when electron move from higher to lower state but in nuclear fusion photon emits when neutron turn into proton. Is both correct?

No. Your comment about an electron and photon is correct, but when a neutron decays into a proton (beta decay) a down quark in the neutron decays into an up quark. As the charge of the quarks are different this cannot be mediated by a (chargeless) photon. In fact, the beta decay process is $d \to W^- + u \to e^- + \overline{ \nu } _e + u$. The d emits a $W^-$ rather than a photon.

-Dan

 

[sadaronjiggasha]

I found the fusion thing in a video where they describing how sun emits light to earth.

 

[Nugatory]

I found the fusion thing in a video where they describing how sun emits light to earth.

You cannot understand physics by watching videos.

 

[sadaronjiggasha]

Thank you @topsquark for your reply.

 

[sophiecentaur]

I found the fusion thing in a video where they describing how sun emits light to earth.

The photons produced by fusion in the centre of a star pass energy to the outside over a period of thousands of years. You can’t regard the photons radiated in our direction as ‘the same’ as what’ produced inside.

Read what @topsquark tells you. Videos are mostly way too glib.

 

[sadaronjiggasha]

So according to the equation decay emits electron and neutrino. Am I reading right?

 

[sadaronjiggasha]

Ok I got my answer from another excellent scientist who help me to clear my doubt. I am sharing here it may help others. "neutron decaying into a proton does not produce a photon; you get the neutron, a positron, and a neutrino. Fusion reactions, though, can involve excited nuclei and nuclear de-excitations can produce photons. Also particle-antiparticle annihilations, as well as acceleration of charged particles, in addition to the electron (atomic) transition."

 

[Vanadium 50]

"neutron decaying into a proton does not produce a photon; you get the neutron, a positron, and a neutrino

Which is incorrect. You get a proton, an electron, and an (anti)neutrino.

 

[phinds]

neutron decaying into a proton does not produce a photon; you get the neutron, a positron, and a neutrino

So you start with a neutron and end up with a neutron plus other stuff? Good luck with that.

 

[berkeman]

Which is incorrect. You get a proton, an electron, and an (anti)neutrino.

But wait, so you're saying that the "excellent scientist" found by @sadaronjiggasha to answer his questions is not so excellent?

 

[Vanadium 50]

Excellent!

 

[topsquark]

Ok I got my answer from another excellent scientist who help me to clear my doubt. I am sharing here it may help others. "neutron decaying into a proton does not produce a photon; you get the neutron, a positron, and a neutrino. Fusion reactions, though, can involve excited nuclei and nuclear de-excitations can produce photons. Also particle-antiparticle annihilations, as well as acceleration of charged particles, in addition to the electron (atomic) transition."

To be precise, the neutron decays into a proton and a $W^-$ and the $W^-$ then decays into an electron and an electron anti-neutrino. As to the rest, yes, the fusion reactions are what create the photons that eventually escape from the Sun.

-Dan

 

[sadaronjiggasha]

That was just typing mistake by him. It was very elementary that after decay of neutron it will turn into proton. We all do same while typing. Thinking of one thing and typing other thing. I also forgot to type some word cause human mind run faster than typing.

2nd thing why I called him excellent scientist because he did not ask from where I am getting this no site refference no link he understood what I am asking just reading my question. Thats why I praised him as excellent scientist. How much deeper knowledge he has that he can understand my novice question.

 

[sophiecentaur]

To be precise, the neutron decays into a proton and a $W^-$ and the $W^-$ then decays into an electron and an electron anti-neutrino. As to the rest, yes, the fusion reactions are what create the photons that eventually escape from the Sun.

-Dan

The gamma photons are not the same ones that escape as a range of photons radiated from the surface. These are largely around optical frequencies and arise after many many interactions on the way through.

 

[malawi_glenn]

p-p fusion chain in the sun
https://en.wikipedia.org/wiki/Proton–proton_chain
Also, note the amount of energy relseaed (in form of kinetic energy), which has three purposes:
1) can "ignite" another p-p chain since the protons need kinetic energy to overcome the repulsive electric force in order to fuse.
2) provides an outward pressure to balance the attractive gravitational pull, causing the star not to collpase.
3) heats up the star, which makes it radiate according to a (an almost perfect) blackbody.