what make the magnet to be magnet with magnetic field?

scientist91

Answer please. Thank you very much. I am talking about permanent magnet.

Hootenanny

Scientist, I again reiterate what I said in your previous thread; forums are not an ideal medium from which to learn basic physical principles, you would be much better served with an elementary undergraduate physics book. That said I offer a brief summary of magnetism.

Magnetism is a direct affect of atomic magnetic dipoles, which itself results from two quantum mechanical properties of atomic electrons. Firstly, the electron has an orbital angular momentum which is determined by orbital angular momentum quantum number which falls out of the Schrödinger Equation. This "orbital angular momentum" should not be confused with classical angular momentum in so much as electrons in an atom do not obey classical orbits. This orbital angular momentum results in an orbital magnetic dipole moment which behaves as a classical magnetic dipole moment (think tiny bar magnet).

The second, more dominant factor, is the electron "spin". Again, this spin should not be confused with classical spin (the electrons in an atom don't actually spin on their axis), it is merely a quantum mechanical description of the electron state. Again, this spin quantum number results in a spin magnetic dipole moment.

Now, to occupy the lowest energy states (magnetic dipole moments have an associated potential energy in the presence of a magnetic field) the electrons tend to 'pair up' with other electrons so that their magnetic moments cancel each other out in a full shell/sub shell, it is the partially filled shells/sub shells which result in a net magnetic dipole moment. The atomic dipole moment is simply the sum of all the individual orbital and spin magnetic dipole moments. Therefore, elements / substances with certain configurations / partially filled [sub]shells will be magnetic.

Magnetic Dipole Moment @ Hyperphysics (better than wiki)
Magnetic Dipole Moment @ Wikipedia

scientist91

Ok, man thank you. I know the basics of the physics, but it is hard for me to understand on the English language because it is not my first language. I am from Macedonia so it is hard for me to translate and understand what you're saying, and also I don't know the conceptions on English language. And do u have any picture of that orbital angular momentum? Where do the electrons are moving, different orbital or something? Why some magnetised materials lose their magnetic field? What make the electrons to have that orbital angular momentum?

ZapperZ

If you have a problem in trying to ask a question, and you also have a problem in understanding the answers you were given, don't you think this whole exercise is becoming rather futile?

Here's what I strongly suggest that you do:

1. Read the references given, especially at Hyperphysics.

2. Now, using THOSE references, try to understand the relevant sections that could answer your questions.

3. After you have made an effort to understand those, and if you still could not figure those out, ONLY THEN should you ask here. But don't ask some basic, generic question that requires a whole lesson in physics to understand. That is impossible to do on a forum like this. Ask the specific item that you read that you did not understand. Give the exact reference and the exact location what and where you did not understand.

If not, I don't think anyone has the patience to want to teach you whole textbooks worth of physics. I certainly don't.

Zz.

scientist91

I can't understand so help me.

Hootenanny

To reiterate what Zz is saying and what I have said previously; Forums are not suitable mediums for learning new concepts or material, they are very good if you have specific questions regarding specific parts of physics. You have my sympathy, but this is compounded by the language barrier between a predominantly English speaking forum and your own native language.

What you are essentially asking me/us to do is present virtually whole lectures on parts of physics where you have little or no grounding, this is a virtually impossible task on a forum and even if it were, I am not willing to invest the and effort that it would take. Now, I don't mind offering help to those who have fairly specific questions, and I don't mind writing extended posts, I usually have PF open while I'm working and just check for new posts every now and again; but what your asking is for us to basically write a physics textbook for you. I'll repeat again, you would be best served purchasing an elementary physics textbook or at least reading the references I gave you because from your questions it doesn't seem to me that you have read the links.

Again, I sympathise with your language barrier but you would be best served with a textbook (or at least reading the references).

scientist91

and is the magnetic field energy?

Hootenanny

The magnetic field is not actually energy itself; the magnetic field is a pseudo-vector field, that is, it is just a way of associating a vector with a given point in space. However, magnetic [and electric] fields can store energy such as in an inductor[or capacitor in the case of an electric field]. The energy density (U/V) in a magnetic field (B) can be calculated thus;

[tex]\frac{U}{V} = \frac{B^2}{2\mu}[/tex]

You should realise that the magnetic field is simply a relativistic consequence of the electric field.

P.S. There's no need to tack your question onto the bottom of another [unrelated] thread; you should post new questions as new topics. Thanks

scientist91

Ok, but I don't want to post every topic for every question, so I am searching for similar topics. So how it stores energy?

Hootenanny

Magnetic Potential energy @ Hyperphysics
Energy Stored in an Inductor / Magnetic Field @ Hyperphysics

scientist91

Answer please. Thank you.

Hootenanny

Why do you think that a magnet attracts iron but not wood?

scientist91

try you will see. btw-when the magnetic field is making the electrons obey their upper orbital and make energy circle and then when they release their energy, go down.

Hootenanny

No, you try and see. I expect you to show a little effort to understanding the material.
I honestly have no idea what your talking about

scientist91

And then which orbitals they obey?

And then on which axis they spin?

jackiefrost

Hootenanny - could you explain a little more about why you used the term "pseudo-vector field" to describe the magnetic field? Because of its relativistic nature? Thanks.

Hootenanny

I was simply trying to say that the electrons do not 'orbit' around the nucleus as you would probably imagine. Rather there is some non-zero probability that they exist at some distance from the nucleus; the most probable position [for a given energy level] corresponds to a circular ring around the nucleus somewhat like a classical orbit. However, for any given energy level (n) [and low orbital quantum number (l)], there is some non-zero probability that the electron can be found very close to the nucleus. Therefore, it is best not to say that electrons orbit around the nucleus, rather there is some probability to find an electron somewhere in the electron 'cloud' around the nucleus. I'm afraid that this is elementary QM and will probably seem very 'weird' and counterintuitive if you are encountering it for the first time.
They don't spin at all.