All questions on magnetic field -- let's understand it

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>>8311380

>>8311412
Is there some description for this pic I can find?

electrons travelling at relativistic speeds undergo contraction and this fucks with charge density in regions of space

>>8311380
Magnetic fields cause electric fields, and electric fields cause magnetic fields. That being said the most common source of magnetic fields are moving electric charges, or object moving relative to moving charges (both are equivalent). However, you can also transform a magnetic field into an electric field if you do the right reference frame transformation (I'm actually conjecturing here, I don't take E&M 2 till next term). Electrons know which way to move because they transfer massless vector bosons called photons with other EM carriers which transfers momentum and makes them move a certain way.

2) Integrate lol. The more difficult the charge distribution, the harder the field is to draw. But remember that magnets are always dipoles, so you can always find a north and a south side to orient the magnets and draw field lines to and from.
3) Because their magnetic domain isn't strong enough to react to the magnetic force. All items can be magnetized, even biological material. In fact, go close enough to a so-called "magnetar" and you'll die because the magnets will cause disruptions in the biological processes that run your bodily functions.

How come electrons' magnetic fields due to spin cancel each other given each electron is far away from one another?

>>8311380
Important:
>https://ufile.io/36f17
Amazing, right? :^)

>>8311506
Is magnetism explainable without virtual things like momentum?

Is there actually a magnetic field that pervades all of space or is "magnetic field" just a term we use to describe the values of points at each point in space.

Its a discription of what would happen if we put a "magnetic charge" on a place and what force said "magnetic charge" would experience. It does travel throughout all space because electromagnetism is infinite in its range

>>8311380
A magnetic field is a relative electric field. Moving electrons have a relativistic speed which creates a small gap in the distance of these electrons which would otherwise create a neutral charge.

>>8312151
Didn't quite understand your answer, except for the part about why the relativity comes into play. Electrons never have neutral charge don't they? And how does this gap help?

I still don't understand how does electric field causes magnetic. Is that some spooky action at a distance?

>>8312684
in a wire the charge of the electrons and protons cancel eachother out. When the electrons move the gap between electrons emerges because of relativity and it is no longer neutral

>>8312714
Now I get it, thanks, but how does this create magnetic field?

>physics
>>>/x/

>>8311380
>What causes magnetic field?
lots of things
>How do electrons at each point know what trajectory they must go?
they feel forces
>Is there quantum mechanics involved to answer this question
of course. they aren't answers that will fit in one post though.
>How to draw magnetic field for a given case?
arrows. from a mathematical standpoint, of course
>how do I figure out possible magnetic fields of a cone magnet
you need to solve Maxwell's equations for whatever a "cone magnet" is. There are simplifications and tools to make this easier.
>Why do some materials not react to magnets
everything reacts to magnets. some things react so little you never notice them. some things react oppositely the magnet so it appears there is no magnetic field. there are many ways for things to react to magnetic fields

>>8311702
>How come electrons' magnetic fields due to spin cancel each other given each electron is far away from one another?
In what situation do they cancel each other?

>>8311718
>Is magnetism explainable without virtual things like momentum?
Momentum isn't virtual. you can measure it. And no there are no frameworks that explain magnetism without momentum of some form.

>>8312109
>Is there actually a magnetic field that pervades all of space or is "magnetic field" just a term we use to describe the values of points at each point in space.
The actual field that "pervades all of space" is called the photon field. The magnetic field is a component of the curvature of the photon field, as is the electric field. That being said, you can describe the magnetic field as being a vector value at every point in space.

>>8312134
the first part is incorrect.

>>8312706
>Is that some spooky action at a distance?
Not at all. it plays into the paragraph i wrote above. The electric and magnetic fields are components of a larger object (the photon curvature tensor). The E and M fields themselves transform into one another in different coordinate systems. Its a long answer.

>>8312772
>>How come electrons' magnetic fields due to spin cancel each other given each electron is far away from one another?
>In what situation do they cancel each other?

Always cancelling each other, when the number of electrons with positive spin equals those with a negative spin we get an element that is not attracted by magnets.
Sorry about the loose terminology by the way, not a physicist.