• Support PF! Buy your school textbooks, materials and every day products Here!

Definition of spin?

  • Thread starter pivoxa15
  • Start date
  • #1
2,255
1

Homework Statement


The spin is opposite in direction to the magnetic moment of the electron. Is that because the magnetic moment, u is defined as Ia where a is the area vector and spin is defined with the same direction as if it had components around it that swirl around with the angular momentum being (r)x(v) so is always oppsite in direction to the magnetic moment. So the spin of the proton would always have the same sign as its magnetic moment?
 

Answers and Replies

  • #2
Dox
26
1
Hello.

I don't understand what is your question... perhaps you can rearrange it a little bit.

So...

The spin is opposite in direction to the magnetic moment of the electron.
This is an statement.

Is that because the magnetic moment, u is defined as Ia where a is the area vector and spin is defined with the same direction as if it had components around it that swirl around with the angular momentum being (r)x(v) so is always oppsite in direction to the magnetic moment.
Is this your answer or part of your problem?

So the spin of the proton would always have the same sign as its magnetic moment?
This seems to be a guess of yours, Isn't it?


If you put it clearer, so we can help :wink:

Regards.
 
  • #3
Meir Achuz
Science Advisor
Homework Helper
Gold Member
2,169
63
The electron has negative charge, the proton positive charge.
Mag mom is proportional to charge. Spin isn't.
 
  • #4
2,255
1
The key part of my question is

'...spin is defined with the same direction as if it had components around it that swirl around with the angular momentum being (r)x(v) so is always oppsite in direction to the magnetic moment [since as Meir Achuz said, the spin does not take into account the charge].'

The rest is trying to draw a comparison with something that is understandable classically which is the magnetic moment.

So spin is like the area vector of a spinning particle. However in the electron nothing is spinning. But we still give this area vector. This vector is different to the mangetic moment when the charge is negative.

So I have given a go at answering my own question. Is it correct?
 

Related Threads for: Definition of spin?

  • Last Post
Replies
3
Views
3K
  • Last Post
Replies
3
Views
2K
  • Last Post
Replies
11
Views
3K
  • Last Post
Replies
3
Views
1K
Replies
1
Views
748
  • Last Post
Replies
1
Views
2K
Replies
13
Views
1K
  • Last Post
Replies
0
Views
1K
Top