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...There are a lot of other features that were predicted. For example, it turns out that the spin, the angular momentum, of the cobalt nucleus before disintegration is 5 units of ℏ, and after disintegration it is 4 units. The electron carries spin angular momentum, and there is also a neutrino involved. It is easy to see from this that the electron must carry its spin angular momentum aligned along its direction of motion, the neutrino likewise. So it looks as though the electron is spinning to the left, and that was also checked. In fact, it was checked right here at Caltech by Boehm and Wapstra, that the electrons spin mostly to the left. (There were some other experiments that gave the opposite answer, but they were wrong!)
The next problem, of course, was to find the law of the failure of parity conservation. What is the rule that tells us how strong the failure is going to be? The rule is this: it occurs only in these very slow reactions, called weak decays, and when it occurs, the rule is that the particles which carry spin, like the electron, neutrino, and so on, come out with a spin tending to the left. That is a lopsided rule; it connects a polar vector velocity and an axial vector angular momentum, and says that the angular momentum is more likely to be opposite to the velocity than along it.
— Feynman • Leighton • Sands, The Feynman Lectures on Physics, Volume I
I have a question about the spin and the magnetic field vector. First, according to the description of the experiment the cobalt-60 nuclei were put in upward magnetic field causing the nuclei to line up and orient their spin vector upward also (rotation to the right png) . Nucleus is positive charged object, when it rotates this produces the small circle currents and magnetic field. Before the decay, nucleus spin = 5. After decay, the nucleus spin = 4. Electron spin = 1/2, neutrino spin = 1/2. Total angular momentum must be 5, so electron must rotate to the right also. If it rotates to the right it acquires magnetic field directed downward, because of negative current. What happens next (will electron repel by external field or will it perform the spin flip)? How did Feynman get electrons rotating to the left? Username160611000000 ( talk) 19:47, 12 April 2018 (UTC)
It is easy to see from this that the electron must carry its spin angular momentum aligned along its direction of motion, the neutrino likewise.If it is easy, I think it can be explained using classical mechanics (with some warnings). Here [1] is written
Particles with spin can possess a magnetic dipole moment, just like a rotating electrically charged body in classical electrodynamics.Username160611000000 ( talk) 03:29, 13 April 2017 (UTC)
There is always a well-known solution to every human problem — neat, plausible, and wrong.- H. L. Mencken Tigraan Click here to contact me 11:46, 13 April 2017 (UTC)
Which breeds of dogs are the most cat-friendly (or maybe I should say "cat-tolerant" -- I don't think any of them are actually cat-friendly in the strict sense) and which are the most cat-unfriendly? And on this scale, where do bulldogs fit in? 2601:646:8E01:7E0B:4C74:BE2F:701E:8F7E ( talk) 06:34, 13 April 2017 (UTC)
At a community workshop I sometimes use is a laser cutter and it has what appears to be a red laser pointer used to indicate the location of cuts (the cutting laser is infra-red and can't be seen). I was staring intently at the red dot produced by the laser pointer and a fellow workshop member told me to avoid damaging my eyes by limiting my time spent looking closely at this red dot. In my opinion he misunderstands one of the warning labels talking about scattered radiation which I think is a reference to the 40 W IR laser and does not apply to the red indicator. Obviously a laser pointer used in a presentation presents less harm because the meters of distance mean large dissipation. I'd say that if the manufacturer used a laser pointer harmful to eyes in close proximity they designed a stupid indicator system. -- 129.215.47.59 ( talk) 14:09, 13 April 2017 (UTC)
I'm aware that archives should not be edited. However, I am strongly concerned that some of the commentary below may be taken at face value without due diligence being done. To that end, I'm boldly hatting the discussion below with this comment. I will leave the original question unhatted. Please drop by on my talk page if you have questions. In the interests of health and safety, I would really appreciate the hatting be left as is. Blackmane ( talk) 23:13, 1 November 2017 (UTC) |
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The following discussion has been closed. Please do not modify it. |
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1. Why's it so obscure in the US and presumably Europe for something magnitude 1.50 and only -28°58'?
2. What's the millennium when it straddles the 1st magnitude/2nd magnitude border? Sagittarian Milky Way ( talk) 15:13, 13 April 2017 (UTC)
Science desk | ||
---|---|---|
< April 12 | << Mar | April | May >> | April 14 > |
Welcome to the Wikipedia Science Reference Desk Archives |
---|
The page you are currently viewing is an archive page. While you can leave answers for any questions shown below, please ask new questions on one of the current reference desk pages. |
...There are a lot of other features that were predicted. For example, it turns out that the spin, the angular momentum, of the cobalt nucleus before disintegration is 5 units of ℏ, and after disintegration it is 4 units. The electron carries spin angular momentum, and there is also a neutrino involved. It is easy to see from this that the electron must carry its spin angular momentum aligned along its direction of motion, the neutrino likewise. So it looks as though the electron is spinning to the left, and that was also checked. In fact, it was checked right here at Caltech by Boehm and Wapstra, that the electrons spin mostly to the left. (There were some other experiments that gave the opposite answer, but they were wrong!)
The next problem, of course, was to find the law of the failure of parity conservation. What is the rule that tells us how strong the failure is going to be? The rule is this: it occurs only in these very slow reactions, called weak decays, and when it occurs, the rule is that the particles which carry spin, like the electron, neutrino, and so on, come out with a spin tending to the left. That is a lopsided rule; it connects a polar vector velocity and an axial vector angular momentum, and says that the angular momentum is more likely to be opposite to the velocity than along it.
— Feynman • Leighton • Sands, The Feynman Lectures on Physics, Volume I
I have a question about the spin and the magnetic field vector. First, according to the description of the experiment the cobalt-60 nuclei were put in upward magnetic field causing the nuclei to line up and orient their spin vector upward also (rotation to the right png) . Nucleus is positive charged object, when it rotates this produces the small circle currents and magnetic field. Before the decay, nucleus spin = 5. After decay, the nucleus spin = 4. Electron spin = 1/2, neutrino spin = 1/2. Total angular momentum must be 5, so electron must rotate to the right also. If it rotates to the right it acquires magnetic field directed downward, because of negative current. What happens next (will electron repel by external field or will it perform the spin flip)? How did Feynman get electrons rotating to the left? Username160611000000 ( talk) 19:47, 12 April 2018 (UTC)
It is easy to see from this that the electron must carry its spin angular momentum aligned along its direction of motion, the neutrino likewise.If it is easy, I think it can be explained using classical mechanics (with some warnings). Here [1] is written
Particles with spin can possess a magnetic dipole moment, just like a rotating electrically charged body in classical electrodynamics.Username160611000000 ( talk) 03:29, 13 April 2017 (UTC)
There is always a well-known solution to every human problem — neat, plausible, and wrong.- H. L. Mencken Tigraan Click here to contact me 11:46, 13 April 2017 (UTC)
Which breeds of dogs are the most cat-friendly (or maybe I should say "cat-tolerant" -- I don't think any of them are actually cat-friendly in the strict sense) and which are the most cat-unfriendly? And on this scale, where do bulldogs fit in? 2601:646:8E01:7E0B:4C74:BE2F:701E:8F7E ( talk) 06:34, 13 April 2017 (UTC)
At a community workshop I sometimes use is a laser cutter and it has what appears to be a red laser pointer used to indicate the location of cuts (the cutting laser is infra-red and can't be seen). I was staring intently at the red dot produced by the laser pointer and a fellow workshop member told me to avoid damaging my eyes by limiting my time spent looking closely at this red dot. In my opinion he misunderstands one of the warning labels talking about scattered radiation which I think is a reference to the 40 W IR laser and does not apply to the red indicator. Obviously a laser pointer used in a presentation presents less harm because the meters of distance mean large dissipation. I'd say that if the manufacturer used a laser pointer harmful to eyes in close proximity they designed a stupid indicator system. -- 129.215.47.59 ( talk) 14:09, 13 April 2017 (UTC)
I'm aware that archives should not be edited. However, I am strongly concerned that some of the commentary below may be taken at face value without due diligence being done. To that end, I'm boldly hatting the discussion below with this comment. I will leave the original question unhatted. Please drop by on my talk page if you have questions. In the interests of health and safety, I would really appreciate the hatting be left as is. Blackmane ( talk) 23:13, 1 November 2017 (UTC) |
---|
The following discussion has been closed. Please do not modify it. |
|
1. Why's it so obscure in the US and presumably Europe for something magnitude 1.50 and only -28°58'?
2. What's the millennium when it straddles the 1st magnitude/2nd magnitude border? Sagittarian Milky Way ( talk) 15:13, 13 April 2017 (UTC)