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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Will a moving neutron produce a magnetic field around it?

Will a moving neutron produce a magnetic field around it? I know that neutrons have no charge, so magnetic field should not be produced along it...but neutrons have a magnetic moment. So why can't ...
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3answers
103 views

Curie temperature and magnetization?

If an ferromagnetic object is heated and reaches Tc the magnetization gradually drops as we get closer to Tc or it's a instant drop? Can I assume as I heat the object, the magnetization is weakening ...
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1answer
107 views

is it possible to have magnetic flux density B not in the same direction of magnetic field intensity H?

it is said that direction of magnetic flux density B in the same direction of magnetic field intensity H for isotropic media so what is isotropic media and is it possible to have B not in the same ...
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1answer
113 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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82 views

magnetic fields and symmetry

When we compute the magnetic field for some configuration (with enough symmetry), we usually use the fact that the magnetic field is orthogonal to any plan of symmetry for the distribution of current ...
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125 views

Hollow electromagnet functionality? (Graphic Models Included)

Question: Will this work as I've shown it here, more or less, or will the iron cylinder being hollow produce results not shown? Topic: I'm experimenting with magnetic fields and have been testing ...
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0answers
590 views

How to calculate magnetic pole strength?

I have 2 magnets. I need to know the force between them. In a previous Phys.SE question, conclusion was: we need to use a dipole-dipole interaction equation, which included m, which the magnetic ...
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1answer
96 views

Why can coercivity be used in place of magnetization when modelling permanent magnets?

I'm trying to understand how permanent magnets can be modeled in finite element methods. FEMM's manual, here, states that it treats a PM as a solenoid with the same surface current as the PM, and then ...
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1answer
988 views

Force between two bar magnets

I need to know how to calculate force between two bar magnets. I searched and found an answer on Wikipedia, but I don't really trust Wikipedia, a lot of crazy stuff is posted there. So I searched ...
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1answer
54 views

How many domains are there in a ferromagnetic material?

How many are there? Also what is the size of those domains? Finally, when domains align with exterior magnetic fields do they move or are they all fixed? I assume they are all fixed because the atoms ...
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1answer
174 views

Why are lab Magnets painted red?

Wy are lab magnets painted red in color? I tried searching everywhere but couldn't get a satisfactory answer.
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44 views

Energy required to demagnetize a soft iron?

How much energy is required to demagnetize a soft iron ferromagnetic material, that has a very low coercive force And a small hysteresis area? Also, would it be possible to demagnetize that same ...
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1answer
114 views

Magnetic field lines and knots

As I was reading the book The Trouble With Physics, I encountered a small paragraph which seemed bit confusing. The paragraph goes as follows: Picture field lines, like the lines of magnetic field ...
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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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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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8answers
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Can the magnetic lines of force of two or more magnets intersect each other?

I know the basic property of magnetic lines of force,that they can never intersect each other.But,I don't know whether it mean -magnetic lines of force of same magnet can't intersect each other,but ...
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2answers
294 views

Energy density in Magnetic fields?

I don't understand what does magnetic field energy density stand for? The possible work that the magnetic field can do? So we can calculate the amount of "work" it can do just from the energy density? ...
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1answer
57 views

does the current's direction on a loop with a magnetic field affect the torque?

I have a question in my book The question is very easy, but then my solutions manual gave me unexpected answers I don't get how in d) they conclude the vectors go in the opposite direction, but ...
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1answer
252 views

Hamiltonian matrix off diagonal elements?

I'm trying to understand how Hamiltonian matrices are built for optical applications. In the excerpts below, from the book "Optically polarized atoms: understanding light-atom interaction", what I ...
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47 views

Magnetization energy density and Magnetic field energy density.

Are they the same? I mean the energy required to magnetize/demagnetize a ferromagnet is highly dependent on the hysteresis loop that is $E= \int H dB$. The energy density of the same field is equal ...
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3answers
692 views

How does electromagnetic induction happen?

Electric and magnetic fields are different from each other(i think i am correct).. How does changing magnetic field induce electric current???
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3answers
158 views

Is there energy stored when iron is magnetized?

When a piece of iron is magnetized, and the domains are aligned, Is there energy stored? If so, how much energy is stored? If there is an attraction between that same iron and the source of the ...
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0answers
121 views

Question about superconductivity

A long cylinder of radius $R$ is made from two different material. Its radius $r<r_0$ $(r_0<R)$ part is a material with superconducting transition temperature $T_1$, and its $r_0<r<R$ ...
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1answer
69 views

Magnetic deviation of a uniform external magnetic field in the presence of a well-defined iron object

Suppose initially I have a uniform magnetic field. Now, in this formerly-uniform magnetic field, I place an un-magnetised cylindrical body of iron into this field of known dimension, with the axis of ...
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1answer
272 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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3answers
246 views

Will a ferromagnet retain its magnetic properties after reaching the curie point?

If a piece of iron or any kind of ferromagnet reaches its Tc, it will lose all it's magnetic properties, and will not be affected by an external magnetic field, if it drops back to room temperature or ...
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0answers
97 views

Variation of electric field and current flowing

Theoretically, a change in either electric or magnetic field will cause a current to flow , I am already familiar to Faraday's law of electromagnetic induction, so I tried to search about producing a ...
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207 views

Rate of change of magnetic flux and the speed of the magnet

The faradays law is $-N*A* \frac{\Delta B} {\Delta T}$ which is the rate of change of magnetic flux times area. How to find out the voltage induced when the magnet moves through the coil and exits ...
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1answer
118 views

Magnetic induction in Relativity

As we know magnetic phenomenon is a mere relativistic effect.My question is how to explain the magnetic induction in a relativistic manner?
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15 views

Is imperative magnetic flux the capacity of individual atoms, or the constituent valency of chemically-bonded molecules within a vacuum?

If magnetic energy depends on the electron poles within two-fields within a permanent magnets void, how do invidiual atoms react within the attraction or repulsion of poles, and what incurrence does ...
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1answer
455 views

Why magnetic field lines and force are not orthogonal with magnets?

The below explanation why magnetism exists is superb in this video. The explanation about magnets is also great in this video. A magnet has atoms with unpaired electrons forming mini magnets. The ...
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2answers
215 views

Why moving charges causes Magnetic Field (module and direction)?

Why an constant electric current in a wire produces a magnetic field, that circles that wire? I know that this question was posted before. However, all answers talk about Maxwell equations, axioms, ...
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1answer
156 views

Questions on electric field formed in conductor and the magnetice field it moves through

When a conductor (e.g. a wire) is moving through a uniform magnetic field, it will create a electric field in the wire as the magnetic field exerts a force on the moving conduction electrons in the ...
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0answers
91 views

Force of a magnet in a magnetic field?

Let's assume you have a simple bar magnet in a magnetic field. I know that the tendency is for the magnet to line up with the magnetic field. I'm trying to figure out how much force that actually ...
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1answer
203 views

Lorentz Force Law and cycloid motion

The question I have is from Intro to Electrodynamics by Griffiths (Page 206, Example 5.2) http://imgur.com/a/sfBlt When using the initial conditions $y(0) = z(0) = 0$, I get: $y(0) = 0$ implies ...
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2answers
1k views

Non-conservative electric fields due to changing magnetic flux?

What I read in several places, tells me that, the fact Coulomb's Law follows inverse-square law and gives a force which is radial, implies that a static electric field must be conservative.(In short, ...
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1answer
99 views

What's the significance of the definition of T1 and T2 relaxation times

In MRI we measure $T_1$ and $T_2$ relaxation times. $T_1$ relaxation time is defined as the time it takes for the longitudinal component of magnetization to recover $1-1/e$ of its original value, and ...
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110 views

Magnetic field strength of a hydrogen electron

Does the rotation of the electron around the hydrogen nucleus cause a resultant magnetic field in the atom? If so, the current density must be very high and the resulting field should affect the ...
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1answer
155 views

Uniform constant magnetic field and traditional attractive force

Why uniform constant magnetic fields can not exert net force on a piece of iron whatever strong it might get?
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Magnitude of magnetic field at the center of circular wire

I'm preparing for an exam by solving the sample questions , here is the one I'm having difficulty with : Following is the given circuit. Which contains two resistance $R_1$ and $R_2$ in form of ...
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1answer
112 views

Which magnetic force is stronger? Electron or proton?

Assume the particles generates the magnetic field with their own spin. No motions except spin.(they have their intrinsic angular momentum.) Then which one generates stronger magnetic force? I've seen ...
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513 views

Magnetic field of solenoid in cone shape

I have done some drawings of the magnetic fields of cone shaped solenoid electromagnets. I based this on the work of Tesla and some explanations of Bashar, known as the Bashar Cones. I found very ...
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1answer
236 views

Can an asteroid have a magnetic field?

Some M-type asteroids are believed to be metallic, even possessing Nickel-Iron. Given the proximity of the asteroid belt to Jupiter's magnetosphere, the regularity of motion of any given M ...
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2answers
87 views

Horizontal magnetic attraction?

I came across and interesting effect today, I have a dozen of Neodymium magnets around my house. And, they are very strong. Anyhow, one of them got attracted to my large steel plate table(use for ...
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0answers
172 views

Two magnets with Iron truncated cone or pyramid. How low inclination can the truncated cone or pyramid be made?

Two magnets with Iron truncated cone or pyramid: Frustrum How much low inclination can the truncated cone or pyramid: Frustrum be made, without non homogeneous lines of magnetic field coming out from ...
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1answer
57 views

Energy spent by motor in a period

Consider a single coil that is turning in a constant and uniform magnetic field thanks to a motor. The normal to the coil is given by: $${\bf u}(t)=\sin (\omega t){\bf u_x}+\cos(\omega t){\bf u_z}$$ ...
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188 views

Infinite long current carrying wire inside a infinite long solenoid

The magnetic field due to a long infinite solenoid is zero outside the solenoid. If there is a long infinite current carrying wire at the axis of this solenoid then The field is non-zero outside the ...
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0answers
55 views

Maximise magnetic force at one point while minimizing at another

Is it possible to have a magnet that attracts one object strongly, but not another object behind that first object? Given an (electro-) magnet M above two thin parallel steel sheets P1 and P2 in the ...
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1answer
105 views

Magnetic field when moving into the influence of a ferrous object

Suppose I have a magnetometer I am on the Earth's surface, away from the influence of other magnetic sources. Assuming the magnetometer is aligned with the reference frame, it should read only the ...
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1answer
247 views

Pressure experienced due to magnetic force?

A current $I$ flows in a long thin walled cylinder(parallel to the axis) of radius $R$. What pressure do the walls experience? This is the 263rd problem in Section III from the book 'Problems In ...