Are Protons Magnets? Investigating Spin & Charge

In summary, electrons and protons both have spin and charge, making them magnets. Protons have a north and south pole, with the north pole on top and the south pole on the bottom. The same applies for electrons, but their poles are reversed due to their negative charge. The magnetic fields of these particles loop back on themselves, similar to ordinary magnets. The B field at the proton in hydrogen due to the electron's magnetic moment is approximately one million tesla. Without an electron, the B field would be significantly smaller, around 100,000 T at a distance of 1 angstrom away.
  • #1
davidong3000
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i know electrons have spin and charge which makes them the smallest magnet. protons also have spin and charge. does this mean they are magnets too with a north and south pole?

Precisely where are these poles in relation to the spin axis of the proton and electron?
 
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  • #2
davidong3000 said:
i know electrons have spin and charge which makes them the smallest magnet. protons also have spin and charge. does this mean they are magnets too with a north and south pole?

Precisely where are these poles in relation to the spin axis of the proton and electron?


Yes, protons are magnets, and they precess. So do neutrons oddly enough. In spite of having no charge, they have a magnetic moment, due to the charged and spinning quarks inside them (the quarks' charges cancel out in the neutron, but add in the proton). These facts are behind the chemistry analytical tool NMR, for nuclear magnetic resonance, and that in turn is behind the medical device MRI, magnetic resonance imaging.
 
  • #3
so if i was looking down on the axis of an electron/proton in such a way so that it appears to be spinning anti clockwise, would i be looking at the north or south pole?
 
  • #4
davidong3000 said:
so if i was looking down on the axis of an electron/proton in such a way so that it appears to be spinning anti clockwise, would i be looking at the north or south pole?
The magnetic moment of the proton is in the same direction as its spin, so its N pole would be on top. The electron magnetic moment is oppositeto its spin direction because the electron is negatively charged.
Its top pole is a S pole.
Note, even though these particles have "spin", they are not rotating.
They are said to have spin because they have angular momentum.
This follows from relativistic QM (the Dirac equation) without their actually rotating.
 
  • #5
Meir Achuz said:
The magnetic moment of the proton is in the same direction as its spin, so its N pole would be on top. The electron magnetic moment is oppositeto its spin direction because the electron is negatively charged.
Its top pole is a S pole.

Can u define "top"?
 
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  • #6
The north pole would be at the "top" of the earth.
By "top" I meant where the head of the arrow woud be in the right hand rule for rotation. (If fingers curl in direction of rotation, the vector omega is in the direction of the thumb.)
 
  • #7
Meir Achuz said:
The north pole would be at the "top" of the earth.
By "top" I meant where the head of the arrow woud be in the right hand rule for rotation. (If fingers curl in direction of rotation, the vector omega is in the direction of the thumb.)

And actually the magnetic "pole" of the Earth on the north pole is ...
a magnetic south pole !
 
  • #8
vanesch said:
And actually the magnetic "pole" of the Earth on the north pole is ...
a magnetic south pole !

so Earth is like a giant electron then . xcept Earth is not - charged. both Earth and electrons have their s pole on top according to rh rule.

so exactly how many teslas are single electrons and protons spitting out? and do the magnetic fields of these charged particles loop back on themselves from top to bottom like on ordinary magnets?
 
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  • #9
davidong3000 said:
so Earth is like a giant electron then . xcept Earth is not - charged. both Earth and electrons have their s pole on top according to rh rule.

so exactly how many teslas are single electrons and protons spitting out? and do the magnetic fields of these charged particles loop back on themselves from top to bottom like on ordinary magnets?
The second answer is yes.
The first answer is a bit messy to calculate, but I get that the B field at the proton in hydrogen due to the electron's magnetic moment is about
one million tesla.
 
  • #10
Meir Achuz said:
The second answer is yes.
The first answer is a bit messy to calculate, but I get that the B field at the proton in hydrogen due to the electron's magnetic moment is about
one million tesla.

what if it didn't have an electron? say a lone proton or lone electron, what would the tesla reading be?
 
  • #11
davidong3000 said:
what if it didn't have an electron? say a lone proton or lone electron, what would the tesla reading be?
I used the H atom just as an example for the B field a distance of 1/2 angstrom away from a lone electron. The B field would fall of like 1/r^3, so an electron's B field would be about 100,000 T 1 angstrom away.
The B field of a proton would be about 600 times smaller than that of an electron at the same disstance.
 

1. What is the spin of a proton?

The spin of a proton is a fundamental property that describes its intrinsic angular momentum. It is quantized, meaning it can only have specific values, and is typically denoted as 1/2. This means that the spin of a proton can only be either up or down.

2. How does the spin of a proton relate to its charge?

The spin of a proton is independent of its charge. While the charge of a proton is positive, its spin can be either up or down. This means that a proton with an up spin and a proton with a down spin will have the same charge. Spin and charge are two separate properties of a proton.

3. Are all protons the same?

Yes, all protons have the same spin and charge. This is because protons are fundamental particles, meaning they cannot be broken down into smaller components. As such, they all have the same properties, including spin and charge.

4. How is the spin of a proton measured?

The spin of a proton can be measured using a technique called nuclear magnetic resonance (NMR). This involves placing the proton in a strong magnetic field and observing the energy levels of the spin. The difference in energy levels can be used to determine the spin of the proton.

5. Can protons be used as magnets?

While protons have a magnetic moment due to their spin, they are not commonly used as magnets. This is because their magnetic moment is relatively weak compared to other materials, such as iron or neodymium. However, protons are essential in the creation of MRI machines, which use strong magnetic fields to image the body.

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