For questions that utilize the concept of magnetic fields (commonly denoted by the letter B), or for questions whose answers likely involve magnetic fields. More specific than the [tag:magnetism], as questions about the phenomenon & theory of magnetism do not necessarily involve the discussion of ...

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3answers
63 views

development of magnetism in a magnet [closed]

If we cut a magnet, the magnetic field develops. But if we cut it vertically, then will the magnetic field develop?
4
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1answer
53 views

Why do these calculations of EM fields for a magnet and wire loop seem inconsistent?

Suppose you have a conducting circular wire loop and a magnet moving towards each other. They move along the $z$ direction with nonrelativistic constant speed $v$. Let the $B$ field of the magnet in ...
2
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1answer
45 views

Why a motionless proton doesn't feel any force in a magnetic field according to special relativity?

In this ( https://www.youtube.com/watch?v=1TKSfAkWWN0 ) specific video uploaded by Veritasium on YOUTUBE , we come to know about how special relativity makes magnets work. We observe that when a ...
40
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4answers
6k views

Is Earth really a magnet?

I am a student of class 9. When I was going through magnetism and read that an earth is a magnet I got some doubts. My question is: is earth really a magnet? Doesn anyone have any proof that earth is ...
2
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1answer
47 views

How to define a the outward direction of 4d simplex?

For a 2d simplex (triangle) with three vertices a,b,c, we could define the outward direction of the face as a-b-c, like define a magnetic field induced flux. For a 3d simplex (tetrahedron) with four ...
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0answers
30 views

When a coil makes a complete turn, why is does magnetic flux double with respect to time?

EMF, $\mathcal{E}$, is equal to -d($\phi$)/dt Where $\phi$ is magnetic flux. Why is it that if from $t_1$ to $t_2$ the coil makes a complete turn and during this turn the normal vector's angle with ...
2
votes
1answer
32 views

Entangled spins in a uniform magnetic field

I have been trying to calculate the time derivative of the expectation value of the operator representing the spin components of a a singlet state (e.g. sigma(z)tau(z)). I formed the tensor product of ...
22
votes
3answers
4k views

Extra strong magnet which doesn't demagnetize credit cards. How does it work?

I've just bought this case for my mobile phone. It has three credit card slots, which isn't strange at all, but in combination with a strong magnet closure, it almost seems a bit stupid, because, who ...
1
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0answers
40 views

Current carrying wire to suspend in midair? [closed]

A straight current carrying wire is inserted in a region of space where a strong magnetic field is directed vertically downward. How can the wire be oriented so that it is suspended in midair by the ...
0
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0answers
43 views

Current through moving bar on rails with non-constant magnetic field

I am working on the problem pictured below and I cannot figure it out. I have been using the equation d[flux]/dt = -BLv and V = -d[flux]/dt. However, since the magnetic field is not constant through ...
0
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0answers
27 views

How does mass of magnet with current-flowing wire inside change?

We just did an experiment where we put a coil inside of a magnet and let certain current run through the coil and measure the mass change of the magnet. I have looked/researched in textbook and ...
0
votes
2answers
120 views

Magnetic flux density of a solenoidal electromagnet

I am designing an electromagnet which will be used to test magnetic sensors. So I used to formula found at hyperphysics which relates the magnetic field flux density to the number of turns, the ...
2
votes
2answers
115 views

How to find the direction of an eddy current?

Suppose there is a magnetic field going from left to right. Suppose a thin sheet of metal conductor (e.g. a 1m*1m square) is dropped through the magnetic field such that the plane of the conductor is ...
4
votes
5answers
653 views

In what case does a Coil with Current flowing through it NOT produce a Magnetic Field?

According to what I've studied, when Current flows through a Coil, a Magnetic field is produced. Recently, I've been told that there is a case in which Current flows through a Coil Without producing ...
0
votes
1answer
43 views

Is there an intuitive explanation for the direction of the B field around a wire?

A wire has cylindrical symmetry, therefore we should consider the possibility of the induced by field in the p,phi and z directions. I know from the right hand rule that we only get a field in the phi ...
1
vote
1answer
38 views

Will my data drives be safe in an emp event? [closed]

If there was an emp event (maybe because the rotation of magnetism of the earth or an atomic bomb) would the data on my hard drives, ssd, dvd, mini dvi tapes and cassette tapes be safe?
0
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1answer
37 views

Electric and magnetic fields with synchrotrons

Can anyone describe to me one change to the electric field and one change to the magnetic field that MUST take place as particles gains energy in a synchrotron accelerator? This could also just be an ...
2
votes
0answers
32 views

Landau levels in ferromagnets

Consider a spontaneously magnetised (uniformly) conducting ferromagnet. Now suppose that there is no external magnetic field. The question is as follows: will the motion of electrons be quantized via ...
-1
votes
1answer
26 views

Why is $\theta$$ = $$\theta$$_{2}$ and not Phi in this Magnetic Field due to Current in Loop Equation [closed]

I'm wondering how we know that $\theta$ = $\theta$$_{2}$ (essential to solving the problem) and that it is not equal to, for example, ϕ?
1
vote
1answer
123 views

$\pi$, $\sigma$ - atomic transitions with respect to the magnetic field axis

I am confused about the atomic transition with different polarized lights. I post the pictures as follows. There are four cases. In case 1, the right-handed circular polarized light ...
1
vote
1answer
67 views

Will a small magnet affect an insulated computer wire?

I'm designing something that involves a small magnet, probably about 0.5m in diameter, which will rest next to a computer wire carrying data, video, audio, etc. If the wire is insulated (think USB or ...
0
votes
0answers
33 views

Can measurement of Spontaneous Magnetization and susceptibility lead one to deduce the magnetic structure of a magnetic compound?

For a given magnetic compound, spontaneous magnetization and susceptibility are measured at various temperatures (in this paper). (SMS measurement) From neutron diffraction data the compound is found ...
0
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1answer
25 views

Does an infinite solenoid have constant magnetic field along its length?

So I'm aware of the fact that an infinitely long solenoid has radially uniform(constant) magnetic field inside. But does the magnetic field vary as one moves along its length? Reading the solenoid ...
3
votes
2answers
106 views

How strong would the Earth's “magnet” be if it was the size of a fridge magnet?

If you shrunk the "magnetic part" from inside the Earth down to a fridge magnet size, how strong would it be in Gauss? This is not a home work question. I just watched this video which included the ...
2
votes
0answers
24 views

Formation of vortices in superconductors

So I'm trying to understand how mixed state of a type II superconductor becomes the energetically favourable state. I've been through a simple approximate calculation considering a S-N boundary to ...
0
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1answer
49 views

Can an electric field help generate a current?

What i know or am guessing:- A moving/changing magnetic field creates an electric field. So if we take a rotating magnet near a coil of copper wire, it will induce a current right. So it means an ...
0
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1answer
41 views

The origin of Gauss' law for magnetism [closed]

What is the physical axiom leading us to the Gauss' law for magnetism?
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0answers
28 views

What physical properties affect magnetic attraction between a magnet and a surface?

What physical properties of a metal affect how strongly a given permanent magnet will be attracted to the metal? How do these properties relate to real-world materials that can be purchased either as ...
0
votes
1answer
55 views

Finding the limit for $\theta$

To find out the magnetic field for infinite wire, we can have an equation $$B= \frac{\mu_0 I}{4\pi s}(\sin\theta_2 - \sin\theta_1) $$ But how the limit of theta could be $\theta_1 = -\pi/2$ ...
0
votes
1answer
45 views

What is an awkward constant and is there a relation to ad-hoc hypotheses?

[I'm not entirely sure whether this is the right board, since it is not a technical but a soft question]. I'm reading the textbook "Spin Dynamics - Basics of Nuclear Magnetic Resonance", 2nd ed., ...
0
votes
1answer
34 views

Why is $\ell$ in $\mathbf F = I~\ell \times \mathbf B$ taken as shortest distance?

The equation $\mathbf F = I~\ell \times \mathbf B$ works good for a straight wire. But in cases where the wire is bent in the form of a sine curve or in a circle and the magnetic field is assumed ...
0
votes
1answer
33 views

How does one magnetic field effect another

Do the fields cancel or are they additive or something else. Can we direct and focus them and or amplify then with similar fields? Can we eliminate the electric portion of an electromagnetic field?
1
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2answers
40 views

Shorting a Superconducting Coil with A/C

When a superconducting coil carrying a direct current is shorted, it continues to carry the current without loss (approximately), assuming it stays cooled and superconducting. What would happen if ...
0
votes
1answer
11 views

Attracting atmospheric positive ions to carbon nano tubes for collection

Can nano magnets built into carbon nano tubes be used to attract moving positive ions from atmosphere to increase the resultant positively charged collecting mass?
1
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2answers
152 views

Does a changing magnetic field impart a force on a stationary charged particle?

Does a collapsing and re-establishing magnetic field impart a force on a stationary charged particle ? Does the charge particle get repelled and or attracted ? Does it move or spin ?
0
votes
1answer
56 views

Can a magnetic or electric field deflect subatomic particles?

I always wondered if the subatomic particles can be deflected by a magnetic or electric field. Basically I am asking the viability of the typical "Force Field" in movies.
0
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0answers
26 views

Induced emf around plane wing tips- varying magnetic field(revised)

I understand that a solenoid wire with an induced magnetic field can be subjected to a varying magnetic field. My question is if you can you have a varying magnetic field around the wing tips of an ...
1
vote
0answers
31 views

The Earth's gravitational magnetics [closed]

The Earth has magnetic properties correct, so can they be measured and if so what are some consistencies?☆
3
votes
3answers
93 views

Why not a magnetic field local maximum?

Reading a brief on magnetic traps I've read that you can't have a magnetic field local maximum. I believe this is linked to the divergence of B being 0 in vacuum, but I don't see why one can have a ...
0
votes
1answer
33 views

Is there a current in this situation?

If a wire moves through a magnetic field a current is induced in the wire. If you drop a piece of wire through a magnetic field, the wire is of a finite length and the whole length is shorter than ...
1
vote
0answers
54 views

interaction of permanet magnetic field with electromagnetic field

I am working on non contact breaking system for a rotating permanent magnet in an electromagnetic field.so I would like to know if the interaction between the magnetic field and an electromagnet will ...
1
vote
1answer
80 views

Probability current for electron in uniform magnetic field: wave function forever splitting apart?

In this document http://hitoshi.berkeley.edu/221a/landau.pdf on Landau levels, in section 4, page 19, "Transitionally invariant Gauge", they analyze the free electron in a uniform magnetic field ...
0
votes
0answers
19 views

What's the relation to calculate the magnetic field away from a magnet?

The relation to calculate the magnetic field generated in a point P in front of a solenoid is : $$ B= N \frac {\mu_0 I} {2a} sin^3(\alpha) $$ with the values' meanings shown in the image. Now what ...
0
votes
2answers
41 views

What is the optimal disposition of coil to maximize the magnetic field created?

I am trying to create a powerful magnetic field using coil, and possibly some ferromagnetic metal bars. The white box with the X on it, is empty, or made of air. Saying that I have no limits on ...
3
votes
1answer
115 views

If light is affected by gravity, does that mean gravity affects electrical&magnetic fields too?

Since we observed that masses indeed bend the light, and since we consider light to be composed of electrical and magnetic fields, does that mean a single point charge will result with bent electrical ...
0
votes
1answer
70 views

Number of states in a given Landau level

For an electron in a uniform magnetic field, in free space, we seek to find the number of allowed states in a given rectangle $L_x L_y$ (for some fixed Landau level). In effect we are tiling 2-D ...
1
vote
1answer
60 views

Equation to describe the magnetic field sensed by a magnetometer

There are a magnetometer and a magnet placed at some distance D from it. We can assume that the magnet is a generic bar magnet. We can also assume that the Earth magnetic field is zero since the ...
0
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1answer
32 views

Is the magnetic force on a current carrying conductor dependent on velocity?

A current carrying conductor is kept stationary in a region of uniform magnetic field, and another conductor, carrying the same amount of current, is moved with a certain velocity in a region of ...
0
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0answers
37 views

Using an Earth magnetic or electric field to fly [duplicate]

Are there possibilities to use the magnetic or the electric field of earth to let a matter flow in space?
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1answer
69 views

Can I create a static electricity water magnet?

I came to watch a video that water dipole get attracted by static electricity. I wanted to know if I could make a static electricity device that could pull out all the water from a wet cloth.