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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0answers
21 views

Understanding the CSV data for hysteresis curve

I have performed an experiment to evaluate the slope between H and B. In order to do that, I did the hysteresis experiment in oscilloscope. In the oscilloscope I found a curve like this After I ...
5
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1answer
311 views

Biot-Savart law from Ampère's with multivariate calculus

Let us assume the validity of Ampère's circuital law $$\oint_{\gamma}\mathbf{B}\cdot d\mathbf{x}=\mu_0 I_{\text{linked}}$$where $\mathbf{B}$ is the magnetic field, $\gamma$ a closed path linking the ...
2
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2answers
1k views

Can an insulator have magnetic poles?

Is it possible to make an insulator have two poles like a magnet? If yes, how to make it?
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2answers
431 views

Repelling force of magnets

What happens if I take two strong magnets and press their like-poles towards each other - does the repelling force created by them equals the force I'm exerting on them or does the repulsion force ...
3
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1answer
219 views

How did neodymium magnets get their name?

Like in the question. Why neodymium magnets (Nd2Fe14B) are called "neodymium magnets"? Why not boron magnets? Or iron magnets?
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2answers
83 views

How does magnetism work? (Not asking what magnetism does)

To clarify, if I asked "how does electricity work" I would want "electrons flow from a negatively charged area to a positively charged area", not "it powers electronics like phones" as an answer. The ...
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2answers
102 views

Why can intramedullary rod heat with MRI?

It is said, that steel rod inside body, like funeral nail, can heat while magnetic resonance imaging (MRI). But why? Isn't MRI scanner use constant magnetic field? If the heating effect is caused by ...
1
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1answer
54 views

What does radiofrequency really do in NMR & MRI?

In NMR, the protons’ frequencies are affected by the magnet which makes them precess around its magnetic field so now all protons will have different frequencies according to their environment ...
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2answers
595 views

How does the magnetic field get induced in car's tire?

I was amazed to see how my car's tire started attracting the nuts and bolts, how in the world did it induce the magnetic field? Never heard of such phenomena!!!
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2answers
108 views

If I double the amount of oxygen molecules, do I double the paramagnetic force?

Oxygen is well known to be paramagnetic. If I take one molecule, $O_2$, and measure its paramagnetic force due to externally applied magnetic field, and then add another molecule near the first ...
0
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1answer
155 views

Pulling a bar through a magnetic field

This is a question on magnetic flux and induced voltage. I believe that this problem's answer key is incorrect, and I want to determine whether my opinion is sound. I also want to explore one ...
4
votes
4answers
3k views

How does a magnetic field cause objects to move?

I understand electricity and magnetism and the relationship between them. What I never understood, and never actually seen explained in any book or website, is how opposite magnetic fields cause ...
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0answers
127 views

Cold Fusion and Black Holes [closed]

How does a magnetic field heat and Cool objects? Would an Atom rapidly cooled with a magnetic field release photons? Can solid magnets be used in the same manner? Einsteins cold fusion formula is ...
0
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1answer
48 views

Cold Solid Matter at the End of a Black Hole's Acceleration Disk?

Is it possible that black holes magnetic field are rapidly cooling matter using a type of magneto caloric effect and cold fusion creating new matter only possible with a black hole's gravity? A type ...
1
vote
1answer
110 views

Ampère's law from Biot-Savart law for linear currents with multivariate calculus

My book, W.E. Gettys's Physics, starts from the Biot-Savart law $d\mathbf{B}=\frac{\mu_0}{4\pi}\frac{Id\boldsymbol{\ell}\times\hat{\mathbf{r}}}{r^2}$, ...
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3answers
40 views

Helical motion of charged particle in external magnetic field

When an electron moves in uniform external magnetic field, with velocity not perpendicular, I understand that the magnitude of force is only due to the perpendicular component of velocity and is ...
4
votes
1answer
311 views

Boundary conditions on current carrying wire

I'm trying to simulate by finite elements method Maxwell equations for a current carrying wire. My 3d geometry consists of a cylinder and a box containing it. I will use a mixed formulation and ...
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0answers
23 views

Calculating fields of two magnets [on hold]

I want to use two NEODYMIUM IRON BORON permanent magnets to create a repulsion between them. In which one PM is attached to the robot (which has three wheels and its weight is 5KG) and the another PM ...
2
votes
2answers
122 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 ...
0
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0answers
17 views

Ampere's circuital law and Maxwell's correction based thought experiment [closed]

I just learned about Maxwell's correction in Ampere's law, when he realised that there is a magnetic field near a capacitor even if there is no current. I was wondering about other possible ...
0
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2answers
215 views

What determines the magnitude of force of an electromagnet?

Let's assume that there is an electromagnet with $B = 1 Tesla$ , what is the magnitude of the force it could generate on other dipoles equal to it's surface area? Can the magnitude of force (in ...
1
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1answer
302 views

Force of a solenoid on a ferromagnetic material

As I was trying to find an answer to another problem, I was informed that the equation I was using would not work. The equation I was using was $$F = (NI)^2\mu_0\frac{\text{Area}}{2g^2}$$ If this ...
0
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1answer
32 views

Ferromagnets - Permanent?

When researching about the Curie-Temperature and magnets in general, something got me confused. What is the difference between a ferromagnet and a permanent magnet? In a ferromagnet the spins are ...
1
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1answer
303 views

Calculating the magnetic field from rectangular conductor

I want to apply the Biot-Savart law to calculate the magnetic field at a point created by current flowing through a square/rectangular conductor. More specifically, a trace on a printed circuit board. ...
1
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0answers
28 views

Radius of solenoid on the magnitude of magnetic field

I'm working on a project and have made a solenoid. I want to know the effective parameters on the magnitude of the magnetic field. $$B=μNi$$ In this equation, the radius of the solenoid don't have any ...
1
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0answers
35 views

Magnetic field of one electron

I want to reproduce a calculation of the magnetic field at the atomic nuclei produced by one electron in hydrogen: Maxwell gives us: $\vec \nabla \times \vec B = \mu_0 \vec j$ Doing the surface ...
0
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0answers
11 views

Data analysis for a magnetic hysteresis loop

I'm a physics undergrad and I have MOKE data for a magnetic material (thin permalloy film on a silicon substrate). Here is one of the hysteresis loops I obtained, plotted using python: The form of ...
0
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1answer
22 views

Eddy current induce emf

Q1Suppose there is a wire having AC current so as ac current is alternating it creates back emf wether that back emf produces current ?? If yes then that current is same as eddy current or not?? ...
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0answers
14 views

Magnetising a hollow steel ball from inside

Suppose a hollow iron/steel ball is magnetised from the inside by placing a magnet inside. Will the magnetic field on the outside of the steel ball be fairly uniform? Does anyone know if there's any ...
0
votes
3answers
37 views

relation between amplitude and frequency of a rotating electric field [closed]

I generated a rotating electric field produced by Ex=cos(wt) Ey=cos(wt-pi/2) in x and y directions. I ran a simulation and seems only in certain amplitudes and frequencies it makes a rotating field. ...
1
vote
2answers
71 views

Energy stored in magnetic field [closed]

I have encountered the problem: Find the magnetic energy stored inside a 1m length of wire carrying 10 amp. The wire is 1 mm in radius, and the current density is uniform. I have found a solution ...
0
votes
1answer
545 views

Magnetic fields in transformers and back emf?

i am having some trouble with understanding the magnetic fields inside transformers and how they relate to back emf. My first query is: is the magnetic field produced inside the soft iron core ...
1
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0answers
21 views

Magnets levitation stability

I'm willing to make a levitating stand based on standard magnets. Both the stand itself and the levitating object would have magnets attached, of course the same poles heading each other. I have two ...
0
votes
1answer
209 views

Explanation of force amplification inside a solenoid

For a system being actuated by a motor, the force can be amplified by gearing. The energy is being used for force instead of distance, so it produces more torque but moves slower. For a system being ...
0
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1answer
35 views

$\mathbf{J}$ and $\mathbf{E}$ having the same direction [closed]

Ohm's Law States that $\mathbf{J} = σ\mathbf{E}$ this implies then that $\mathbf{J}$ and $\mathbf{E}$ have the same direction . But we know that $\mathbf{E}$ in normal to a conductor and $\mathbf{J}$ ...
0
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1answer
168 views

What is the magnetic flux density “outside” the solenoid when AC current is passing through it?

I know that there are well defined equations explaining the magnetic flux density in the solenoid. However what about magnetic field outside the solenoid? How is the magnetic flux density related ...
0
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0answers
9 views

Effect of removing material on Magnetization

I realized recently I have some confusion over $\bf{H}$,$\bf{M}$, and $\bf{B}$. Consider some infinite thin plane with permeability $\mu$, and say I know everything else there is to know about it. ...
13
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6answers
28k views

Can magnetic fields be redirected and focused at one point?

I know that magnetic fields can be redirected, but... given a situation where you have static magnetic field over a large area, and you want to quickly change the magnetic field strength. Is it ...
1
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0answers
24 views

Do you know if you have zerovalent iron nanoparticles in liquid how to measure minimal magnetic force required for separation of these nanoparticles?

I think of measuring mag susceptibility from VSM data (magnetization divided by the applied field) but I am not sure if this would be enough. Maybe if I employ SQUID measurements, but in that case I ...
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votes
2answers
148 views

Super massive Black Hole and photon reduction [closed]

This is a picture of 2 galaxies taken from The Hubble. The arrow shows a smaller galaxy's black hole starving of the usual stars because of the binary rotation about the bigger galaxy that is pulling ...
1
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1answer
24 views

Experiment on magnetic line of force

Say hypothetically the electrical current is flowing through the solenoid which is wrapped around a colossal electromagnet which is approximately 1 lightyear long. (Assume there is no resistant so no ...
3
votes
2answers
67 views

How can I use a magnet to lift a paperclip?

This question has been asked already, but no satisfying answer came up. All the answers seem to push the problem further, but do not explain clearly what is going on. I will reformulate it for a ...
1
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0answers
20 views

What's “the” physical explanation of hysteresis in ferrimagnetic materials?

I am wondering what is "the" or "a" physical explanation of hysteresis in ferrimagnetic materials. From what I've read in wikipedia and Cullity's book, there is a simple physical explanation for ...
1
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0answers
12 views

Field line Direction and exerted force

Magnetic field lines of a magnetic field have different directions. What information about the force exerted on a charge will give us the direction of field lines?
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0answers
13 views

Force on a magnetic dipole due to a magnetic field

Imagine a solenoid which has current $i$ and is producing a magnetic field $B$ which equals $$B=\mu N i$$ Now, imagine we put a small cylindrical magnet at the end of the solenoid. Then because at ...
0
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2answers
125 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 ...
0
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0answers
23 views

Force Exerting on a magnetic train

A question is already asked ( How does this “simple” electric train work? ). But I've got a question about it. In order to calculate the force which is being exerted on the system including magnets ...
0
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1answer
27 views

Where does the earths magnetic field originate [duplicate]

To my knowledge my knowledge magnetism comes either from an electric current flowing through an object or from a permanent magnet which can be created by heating certain ferrous metals to specific ...
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3answers
1k views

Generating unlimited electricity through magnets

Well i had seen a toy, which i till date don't know was it battery powered or not? and also could it be used to actually create energy (I know that it is not possible but whats the problem?) ...