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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Force from solenoid

I'd like to approximate the force from a solenoid, or at the very least find a formula which is proportional to the force so that I can experimentally find the constant for my particular case. ...
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How can a magnet have a greater magnetic field strength than a bigger, heavier and more powerful magnet made of the exact same material?

Here are some informations I found on the magnetic field strength (also called "magnetic flux density" or "magnetic induction", commonly denoted as B and expressed in tesla or in gauss) of an average ...
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14 views

understanding shceme field lines - magnetic field

I would like to know if the magnetic field is in "the x-y plane". Does this mean the field lines are actually parallel to the visible line x or y? Or does it mean the field lines are parallel to the ...
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Lifting capacity of superconductors

How does the strength of the magnetic field the superconductor is exposed to affect its ability to levitate/lock heavier objects? Or is there no relationship (for superconductors) between magnetic ...
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6 views

With what frequency triangle swings if it shuns from equilibrium? [on hold]

Guide V-shaped is with no friction in the swivel bearings A and B (see Fig.) Of the magnet with a vertical magnetic field of 0.8 T. The weight of the guide is 50 g, the length AB 4 cm, and the length ...
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30 views

Can a magnetic field be expelled over long arbitrary distances through a super conductor? [on hold]

I'm not a physiscist but i have a creative concept I wish to make into a environmental commercial before my Interactive Feature Film. Apologies, if it sounds like I have no idea what I'm talking ...
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13 views

Nuclear powered flux compression generator?

A flux compression generator is a device for converting the chemical energy of explosives into magnetic field energy, with reported efficiencies of up to 20%. Is there a limit on the conversion ...
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10 views

Electric potential at the wings of a plane

PROBLEM: A plane with wing span 70 meters is flying with a speed of 100 m/s in a uniform magnetic field B = 5 T that is directed vertically with respect to the wingspan. What is the emf produced ...
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91 views

Constant magnetic field attenuation by µ-metal (mu-metal)

I am interested in the magnetic field attenuation by µ-metal. Specifically shielding from earth's magnetic field $\boldsymbol{H}_E$ through closed cylindrical layers of such a metal, yielding an ...
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17 views

What is strength of an electromagnet at a distance?

I want to levitate a permanent magnet between two electromagnets. My two governing equations are: $$F = \frac{B^{2}A}{{2\mu_{0}}}\tag{1}$$ $$B = \frac{NI\mu}{L}\tag{2}$$ Where $x$ is the distance ...
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107 views

Magnetic field of a static disk magnet

I have a magnetic disk (Radius R, height h) that creates magnetic field lines (axisymmetrical). I simulated the field lines, exported the data and am now trying to fit a function into the data to have ...
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16 views

Magnetic field along the line which is perpendicular to the wires

Suppose we have 3 wires which cross at some point $A$. After the branching point, the electric currents in two arms are $I$. And we have the line passing through the point $A$ and perpendicular to the ...
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1answer
16 views

Magnetic field between two rings

Two rings are placed parallel atop each other along an axis with a distance $\epsilon$ which is much smaller than the radius of both rings a. Through one of the rings there is a current I and through ...
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1answer
232 views

Forces on a wire moving in a magnetic field?

When a wire is placed inside a magnetic field and current starts to flow in that wire, that wire experiences the Lorentz force = $IL \times B$ and beings to move. Aside from induced motional - ...
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49 views

Which is the true magnetic field?

In electromagnetism we have the $\mathbf{B}$ field which is the field appearing in the Lorentz force law: $$\mathbf{F} = q(\mathbf{E} + \mathbf{v}\times \mathbf{B})$$ and we have the $\mathbf{H}$ ...
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20 views

understanding magnetic dipole moment and torque [on hold]

I would like yo know if I understand things correctly: Magnetic moment, which is a constant value for a solenoid or magnetic dipole, determines the torque it will experience in a magnetic field. (I ...
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4answers
64 views

Magnetic moment - magnetic field relation without free currents

I'm trying to understand magnetostatics in the presense of ferromagnetic material. But I'm ending up in a contradiction: Lets take a piece of iron: Assuming that we don't care about the hysteresis ...
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2answers
461 views

Why does Earth behave like Natural Bar Magnet?

What is the reason for the Earth to behave like a bar magnet and have poles (North and South poles)?
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35 views

Finding the magnetic field [closed]

A mechanical pendulum is made of a metal rod, one end of which is attached to a string. The mass of the rod is $m$ and the string length is $l$. The oscillation period of the thus obtained pendulum ...
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318 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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10 views

from control torque to magnetic moment

I am designing a system which generates a magnetic field to make itself move in space (a cubesat with magnetorquers). This magnetic field is known as the magnetic control torque, i.e. it will torque ...
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1answer
95 views

Asymmetry in magnetic field direction of an electric wire

The simplest magnetic field is that of an infinitely long wire with uniform current. It does enjoy radial symmetry about the wire and has the variation as 1/r. To find the direction of the resulting ...
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2answers
54 views

Magnetic field outside an infinite solenoid

Can someone explain to me how the magnetic field cancels outside a solenoid of infinite length mathematically (using an integration or something)?
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52 views

Has the effect of magnetic fields on time ever been examined experimentally?

Relativity of time can be examined with satellites as gravitational or acceleration. Is there any similar experiment with intense magnetic fields?
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83 views

What force does a magnetic field of a certain strength apply to an object?

Disclaimer: This question is mostly to fact-check an "Elementary" episode and is not home work related at all. For the curious, in that episode, a "20 tesla magnet" is used to propel bullets inside an ...
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2answers
218 views

Faraday's law and “infinite induction”

I may have confused after thinking too much about Faraday's law. If an emf is induced in a circuit due to some changing magnetic field, the induced current will be in a direction such that the ...
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1answer
147 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 ...
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0answers
22 views

Why is emf 0 for coil rotating in field?

Say you have a coil (that can carry a current) rotating in the field between two magnets. When the area of the coil is perpendicular to the field lines the emf induced in the coil is 0, why is this?
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1answer
52 views

How long does it take a magnet to lose its magnetization? [duplicate]

As we all know, a magnet has some magnetization that lets it attract other ferromagnetic materials but I was wondering how long it takes to lose this magnetization? Is it even possible or not?
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15 views

Can a magnet lose its strength over time? Especially when repulsive magnets are around? [duplicate]

I was thinking of hanging delicate art glass pieces separated by opposing magnets on walls simply using the power of magnets. I was wondering will the opposite poles have any effect on the strength of ...
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2answers
59 views

Does a moving charge have additional (magnetic) energy

My understanding so far: A moving charge produces a magnetic field, B, in an analogous way to a current produces one. A magnetic field has an energy density which is proportional to B squared. My ...
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38 views

What happens to the magnetic field when the source is turned off?

Suppose you had a magnetic field source in space and a piece of iron a light minute away. Assuming magnetic fields propagate at the speed of light since they are massless, if you turn on the magnetic ...
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1answer
171 views

Could the Faraday's rotating wire experiment be explained without using Lorentz force?

I read Faraday's rotating wire experiment which resulted in the invention of the homopolar motor. He was clever enough to think it that way and make the wire rotate around one of the poles of the ...
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2answers
55 views

Why can a magnet setup not fly?

I know that the following setup won't work to lift it up forever: But I'm struggling to convince myself why. If the top magnet is strong enough to lift the weight, why is the bottom magnet not ...
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1answer
236 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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1answer
75 views

Magnetic flux of a loop due to another loop

The scenario is the following, I am given 2 loops with the same radius, r, a distance of d, and same current of I. In the left loop the current goes counter clockwise, in the right loop the current is ...
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0answers
25 views

Magneto Optical Kerr Effects

I have a few questions on MOKE setup. Firstly, why is calibration of the coils necessary? Is it to get a relationship between the voltage and the Magnetic field? Secondly, why do we have to normalise ...
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1answer
241 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 ...
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1answer
35 views

Is the electron's magnetic dipole moment influenced by the measurement method?

The electric charge of an electron at rest is a constant value and is not influenced by the measurement instrument. The measurement instrument by itself can give more or less accurate result, but does ...
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1answer
19 views

To describe crystallity structures of this ferromagnetic material

MOKE microscope picture of the ferromagnetic Material $Co_{40} Fe_{40} B_{20}$ of 20 nm thin film All other pictures look the same, also from different angles: [0,360] by 15 degree separation. I ...
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1answer
230 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. ...
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1answer
24 views

Definition of magnetic field $H$ in ferromagnetism

I am thinking how you can define explicitly the magnetic field $H$ in a ferromagnetic material. I think the Maxwell's equation should apply. However, I am not completely sure which form. Here are ...
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2answers
81 views

Why opposite poles of magnet attract each other, why don't they repel?

We know that different poles of magnet attract each other, but I don't know why this happens why similar poles doesn't attract. what is difference between similar poles and different poles?
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1answer
28 views

Is the magnetic field calculated by Ampere's Law only because of the currents crossing the loop? [duplicate]

In Ampere's Law, $$\oint \vec B \cdot \mathrm d \vec l = \mu I$$ the current outside the curve is not included on the right hand side of the equation.* Does it mean that the magnetic ...
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1answer
53 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 ...
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1answer
30 views

Force on permanent magnet solenoid core

I was wondering, since a coil/solenoid will pull any ferromagnetic material inside it, does the initial magnetization of the object in question affect the magnitude or direction of the force? I know ...
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0answers
47 views

What will be the motion of an electron kept at rest in the vicinity of a magnetic monopole?

Consider that both an electron and a magnetic monopole are kept at rest close to each other. Will this result any motion of the electron? If yes, please give a derivation of the equation of motion.
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1answer
45 views

How does one calculate or even approximate the force observed by a magnet as its dropped inside of a diamagnetic cylinder?

How does one calculate or even approximate the force observed by a magnet as its dropped inside of a diamagnetic cylinder? Wikipedia and Google does not provide much information on this topic. ...
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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 ...