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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The Magnetic Field around the Proton Beams in the LHC

How would one most appropriately model the magnetic field around each bunch of protons in the LHC at maximum operating speed? Is the assumption of a wire of the same length of the beams (~30cm) with ...
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3answers
2k views

Why is my restaurant silverware magnetized? [closed]

Why is my restaurant silverware magnetized? Specifically, if I lay all three flat on the table, and touch the bottoms of the handles together, I can pull the knife with the handle of the spoon. I ...
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1answer
40 views

Why is the geomagnetic north pole at a different location from the magnetic north pole?

According to this site Magnetic North, Geomagnetic and Magnetic Poles The Geomagnetic poles (dipole poles) are the intersections of the Earth's surface and the axis of a bar magnet hypothetically ...
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61 views

Currents and magnetic fields produce forces that affect things they're not touching?

I was doing this past paper and am a little confused by question 5) part c)ii) I correctly calculated that the force acting on the rod due to the magnetic field is 0.016N but I can't see how ...
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2answers
101 views

Are metals more heavy due to the Earth's magnetic field?

Non-metal objects are attracted to the Earth due to gravity. So the weight of non-metal objects can be only dependent on their mass. On the other hand metals can be attracted to the Earth's magnetic ...
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1answer
26 views

What gives Maglev trains forward horizontal motion?

Maglev trains have superconductors which are immune to magnetic field lines with low enough temperature. Due to this property, they levitate on magnetic rails as magnetic field lines are bended below ...
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0answers
27 views

EMF & Magnetic force at the same time?

A conductor is placed in a magnetic field, current starts to flow, and the wire experiences the Lorentz force of $x$ Newtons. However, what confuses me is that $x$ is a value that is calculated from ...
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1answer
60 views

Magnetic Shielding?

Can magnetic fields be "blocked"? For example, in the game, TitanFall, a robot stop bullets with ( presumably ) a magnetic shield. I wish to calculate the magnetic force required to stop a bullet ...
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3answers
124 views

Conservation of energy in electromagnetism?

How is energy conserved in electromagnetism? Is it hinted only from Lenz's law or from Maxwell? Also, if a solenoid's flow of current produces a magnetic field, and from the magnetic field forces are ...
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50 views

how do I calculate the B field (strength and direction) on a point charge due to a permanent magnet

I am trying to create a simple 2D Simulation of magnetic fields similar to this; showing the field lines or the effect of permanent magnets. I keep coming across equations like this: ...
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3answers
75 views

Ferromagnets and magnets tend to align in the center. Why is that?

When you bring a large iron plate and a magnet, the magnet attracts the iron plate and it tends to slide itself to the center. When I place it on the edge, it always aligns at the center why is that?
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Magnetic field of a wire with over 1000 amperes? [duplicate]

Does a large thick wire that has over 1000 amperes of current flowing through it generate powerful magnetic fields? What formula is best here to predict $B$?
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1answer
39 views

Magnetic Attraction in Space [closed]

If I were to attach a 1 inch diameter magnet to lets say a half pipe, that it fits perfectly in, and attach a 1 in diameter piece of iron close enough for the magnet to assert its attractive pull, ...
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2answers
83 views

Is a magnetic field affected by the presence of air?

Does air affect a magnetic field's ability to attract ferromagnets? If a magnetic field and a ferromagnet were placed in a vacuum would there be a better performance?
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1answer
271 views

Can I Demagnetize a ferromagnet with a hammer?

If an iron is exposed to an external magnetic field, the iron's domains are all aligned with that ext-B . If I strike it with a hammer, will it be demagnetized? Comparing it with heat, I know the Tc ...
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2answers
560 views

Is it possible to levitate a toy maglev train using only permanent magnets as long as the train stays in motion?

I am fascinated with magnets, and specifically the idea of magnetic levitation. I recently purchased a Levitron toy maglev train and have enjoyed finding the perfect sweet spot at which it levitates, ...
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1answer
50 views

How does this particle behave in the magnetic field?

I have the above question and I have though about it every way and can't seem to find out. So what I have concluded (ignore the answers on the img) Is that the force is on the z axis because the ...
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0answers
31 views

Field outside a solenoid?

Say you have a solenoid with diameter $d$ and length $L$. How can I show that as $d/L$ approaches 0, the field outside the solenoid is zero? I'm looking for a formal proof involving integration. ...
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0answers
69 views

Mu-metal electromagnetic core?

Is it possibile to use Mu-metal as an core for a electromagnet? Considering thats is has a very high relative permeability? Low coercive force, and low hysteresis losses. And a very very low magnetic ...
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1answer
53 views

Current vs Voltage Drive for Loudspeakers [closed]

Please see this article: here I don't know enough EMFT to comment on this but I am working on other tasks for a wireless speaker system prototype called "Busker's Friend". Completing my Schaum's ...
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1answer
100 views

Is it possible to detect fake Tungsten aka Wolfram gold bars with a strong magnet?

Tungsten aka Wolfram is paramagnetic so it is weakly attracted to magnets. A guy devised the following to test for Tungsten in gold bars: http://www.youtube.com/watch?v=foELQ7T8_90 But he is using ...
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1answer
35 views

Saturation of an iron core?

Lets assume we have a 1 kg iron core, and a 100 kg iron core. Now saturation is defined as how much that core can absorb the magnetic field, since they are different sizes, don't they saturate at ...
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0answers
58 views

Magnetic monopole

I've been watching a lot of videos claiming to make monopoles either by dropping the temperature to 5k (-268° C) and splitting the magnet or by pouring molten metal through an induction system and was ...
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1answer
25 views

How to differentiate between ferri-magnetic and para-magnetic substances?

Both are feebly attracted by a magnetic field. I know the difference between these substances(on why these get attracted to magnetic field) but as both get feebly attracted how to find out whether a ...
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2answers
76 views

Why does a solenoid's field look like this?

My book gives the above diagram but doesn't provide an explanation why the field looks like that. It simply says that the fields mostly cancel leaving the field above. Could someone walk me through ...
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2answers
87 views

Intuition behind Faraday's Law?

Faraday's Law seems more like an observation than an explanation. Sure, a changing magnetic current causes emf, but why? How does a changing magnetic field cause electrons to move in the direction of ...
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2answers
63 views

Terminology for line integral of magnetic field

One of the quantities appearing in the integral form of Maxwell's Equations is the line integral of the magnetic field around a closed loop. (The relevant equation states that this is equal to the ...
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3answers
134 views

Which angle should it be?

in the formula $$dB = \frac{\mu_0l ~|dl \times r|}{4 \pi r^3} $$ and the image where dl is in y-z plane and dB is in x-y plane. the ring conductor is in y-z plane carrying current I in ...
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1answer
277 views

Axial forces on a solenoid windings

I understand that the windings in a solenoid experience a Lorentz force $\mathbf{f} = \mathbf{J} \times \mathbf{B}$, which tend to cause an outward pressure where $\mathbf{B}$ is directed along the ...
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1answer
44 views

Waveguides Transmission Mode Determination

How do I know if I have TE, TM, or TEM rectangular conductive waveguide? For instance, I am doing a lab where we want maximum magnetic field in the waveguide, does that mean we want the TE because ...
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1answer
110 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
106 views

How to Generate a Strong Electromagnetic Field?

I'm working on a project and I need help generating a strong magnetic field over an air gap with the lowest material weight that could be achieved. I have tried to use permanent magnets but its not ...
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1answer
55 views

Ampere's Law and Circulation?

The net circulation should be zero if the net current is zero. However, I don't see how the circulation in the Amperian loop above can be zero. All the lines interact the loop only once and all ...
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1answer
369 views

Determining $y$ coordinate of charged particle motion [closed]

I've tried several different ways, with a tutor, and with other colleagues. One of my colleagues has even gone to the professor with whom he worked out an equation for the component, and it was later ...
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1answer
42 views

Difference between Cotton Mouton effect and inverse Cotton Mouton effect

The Cotton mouton effect is observed when a linearly polarized electromagnetic wave passes through a dielectric medium and a magnetic field is applied perpendicular to the direction of propagation of ...
2
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1answer
64 views

Ferromagnet induced current?

A ferromagnet is attracted to a solenoid's magnetic field. I understand that now the ferromagnet produced a magnetic field, from that process is there an induced $EMF$? Can ferromagnets that are not ...
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6answers
4k views

What are the fields produced around a current carrying conductor?

If you consider a current carrying conductor, every instant an electron enters the conductor, another electron will be leaving the conductor. Thus, the current carrying conductor will not be charged ...
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3answers
194 views

Reducing Eddy current losses

Eddy currents are setup in any metallic block which is in the vicinity of changing magnetic fluxes. These primarily cause heat losses, and in certain cases causes damping of the relative motion ...
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2answers
40 views

Electric motors and change in flux

"When a current passes through an electric motor, the magnetic force on the motor causes a torque on the loop of wire causing it to turn". However, when the loop rotates, there should also be a ...
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0answers
36 views

Expanding the Magnetic field?

A magnetic field $B$ can apply a force $X$ on a ferromagnet when there is no gap to separate them, $r$ = 0. When that gap ($r$) is increased to 3 cm, the force drops to zero. How can that be solved? ...
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4answers
2k views

North and south of magnetic field

The current I is flowing upward in the wire in this figure. The direction of the magnetic filed due to the current can be determined by the right hand rule. Can we determine the north and the south ...
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1answer
43 views

What is the Significance of Magetic Field Energy Density?

If we consider electrostatic field energy density for an electrical field then by analysis we find that it is the representation of the total electrostatic potential energy of the considered ...
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1answer
76 views

Faraday's law question: wire falling over two rails

I'm having trouble with this problem. The picture shows a wire of mass m and length l which slides on two rails, with certain angle with respect to the horizontal.The whole circuit has a resistance R ...
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1answer
137 views

Magnetic field of a solenoid at the poles?

It's known that at the center of an electromagnet/solenoid the magnetic field $B$ is strongest there. At the pole/edge of the solenoid/ or electromagnet is the magnetic field $B$ strong? Let's assume ...
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2answers
1k views

Magnetic poles in Halbach array?

I am a bit confused by the description of Halbach arrays. It is said that the line of magnets aligned in certain way results in cancellation of magnetic field on one side of the array, and ...
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0answers
131 views

Calculating the electro magnetic field strength needed to repel a permanent magnet

I have a design where a permanent magnet is placed on top of an electromagnet. When the electromagnet is powered off, the permanent magnet is attracted to the iron core of the electromagnet. When the ...
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3answers
1k views

Generator using Earths's Magnetic field?

In the past I've been shown Internet sources claiming a specific generator that uses nothing but the earth's magnetic field to generate power, I'm looking for the name of the generator? I realize ...
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0answers
132 views

Explanation for the physics behind magnetic monopoles?

Ok so I am looking for a simple explanation of how the process is done from the information I could access and the knowledge I was allowed I have the idea that it is a matter of quantum physics and ...
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2answers
159 views

Manganese has more unpaired electrons than Iron so why is Iron ferromagnetic Manganese paramagnetic?

Manganese has five unpaired electrons, but Iron has four, then why is Iron ferromagnetic and Manganese paramagnetic? What's that property I'm missing?
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2answers
2k views

What is the difference between an electric and a magnetic field? [closed]

This question is a consequence of another question of mine which is about spin. Here is my spin question. What is the difference between these two fields? How do they occur? Am I right if I say that ...