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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8 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 ...
21
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3answers
2k views

Why doesn't light affect a compass?

In our daily life a lot of photons of visible light, infrared and radio etc move around us. We know that light is an electromagnetic radiation. So why doesn't that electromagnetic radiation affect a ...
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1answer
33 views

Right hand rule confusion

I have a question that I am trying to figure out: Two long parallel wires placed side-by-side on a horizontal table carry identical size currents in opposite directions. The wire on your right ...
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1answer
45 views

Force between two finite parallel current carrying wires

Remark: This is not a homework question...It is pure out of theoretical interest. I asked this the mathematics-community a couple days ago and got no answer, so I figured I'd try here. Most standard ...
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1answer
35 views

Finding magnetic field inside rotating sphere

A sphere with radius $R$ has constant charge density $\rho$ per unit volume. This sphere rotates as a rigid body with an angular velocity of $\omega$ around an axis that goes through the center. What ...
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0answers
17 views

Force on charged particle in magnetic field [on hold]

I am having difficulties achieving the answers to a question in my physics textbook. The question goes: A charged particle $q = 3.0 × 10^{–19}\space C$ and of mass $5.65 × 10^{–27} kg$ moves ...
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1answer
39 views

Using a circuit to make a magnetic balance to weigh objects

I understand that this is a homework question, but I am learning about magnetic fields and things like that and this certainly wasn't covered in the material, so my question is more about the actual ...
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1answer
35 views

magnetic field due to current in a wire using Biot-Savart's law

I am learning about Biot-Savart's law to calculate the magnetic field due to the electric current in a wire. ...
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0answers
36 views

Need help understanding $\oint H \cdot dl = I_{f,enc}$. Homework question [on hold]

A cylinder of radius R and magnetization $M = kr^2 \hat{\phi}$. I already found the magnetic field due to bound charges to be, $B = \mu_0 k r^2 \hat{\phi}$ inside the cylinder and $B = 0$ outside ...
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0answers
15 views

Field in a toroid

How does the field change in the cross section of a toroid? I will give you my attempt at an answer so that you can see what I am trying to ask. I think the field should look something like this: ...
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0answers
22 views

Magnetic susceptibility in ising model as magnetization change

Let's say I have a standard 2D Ising model with $$ H(\sigma) = - \sum_{<i~j>}\sigma_i \sigma_j - h\sum_{j} \sigma_j $$ With the metropolis algorithm, I can compute various things like energy ...
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1answer
16 views

Repelling a weak permanent magnet with an electromagnet

I have a question about magnetic repulsion. Suppose I have a permanent magnet (axially magnetized) placed on top of the iron core of an electromagnet. I want to switch on the elctromagnet to repel the ...
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1answer
19 views

Why does magnetic flux linkage become negative when a coil is turned through 180degrees?

Taking a rectangular coil, in a constant magnetic field, it is understandable that BANcos(theta) should apply for the magnitude of the flux linkage. However if the coil is turned through 180 degrees ...
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2answers
114 views
+50

Spin in magnetic field and eigenvalues

We have some arbitrary quantum state, lets say $$\vert\Psi\rangle=\alpha_{1}\vert\uparrow\rangle+\alpha_{2}\vert\downarrow\rangle= \begin{pmatrix} \alpha_{1} \\ \alpha_{2} \\ \end{pmatrix}$$. And ...
2
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2answers
41 views

Magnetism: why is a steel ball-bearing repelled from a magnet towards a piece of unmagnetised steel?

At the risk of sounding like one of the Insane Clown Posse, I was watching this video of the late Eric Laithwaite discussing magnetism: Eric Laithwaite, Circle of Magnetism (1968) (the relevant ...
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1answer
22 views

Magnetic Field Along the Axis of the Current Ring - Alternative way to compute

This is Example 5.6 in Griffith's Introduction to Electrodynamics (4th Edition): Find the magnetic field a distance $z$ above the centre of a circular loop of radius $\ R$, which carries a steady ...
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0answers
18 views

How to find magnetic moment using android sensors?

I am working on android application which analyze magnetic field and should find position of magnet in predefined space. I am using for development permanent magnetic dipole and android sensors ...
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1answer
21 views

Can an electric current's magnetic field be represented by a magnet/magnets?

Is it possible to recreate the exact same magnetic field that electric currents have with a magnet and if it is, how?
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0answers
3 views

Magnetization Curve of the Coiled Tube HS-90

Could anyone provide the magnetization curve (B-H curve) of the Coiled Tube HS-90, which is made of steel alloy A-606 type 4 molly? Thank you.
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1answer
83 views

Magnetic Force $\mathbf{B} = \dfrac{\mu_{0} \cdot i}{2\pi\mathtt{R}}$? [closed]

Magnetic Force $$\mathbf{B} = \dfrac{\mu_{0} \cdot i}{2\pi\mathtt{R}}$$? I've integrated both sides. $$\mu_0 \cdot i \cdot \log{\dfrac{2 + \sqrt{3}}{2}} \dfrac{\sqrt{3}}{2\pi}$$
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1answer
96 views

Is Magnetic Field is made of Photon? Is there any frequency of Magnetic Field waves? [duplicate]

(Considering the What is a magnetic field question which is asked on just 8th march, by @DragonSlayer3 and my own question which is left with negative points and closed, Photon Energies in sunlight, ...
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0answers
23 views

How can I compare magnetism/mass ratio of different magnets?

I want to compare the magnetism/mass ratio of different magnets. Let, for example be ceramic/samarium-cobalt/alnico/steel/neodymium magnets. Questions: What units should I compare for ...
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3answers
131 views

Question about magnetic force

I have some confusion regarding the magnetic force. I know that the magnetic field created by a moving charge or current EXERTS a force on any moving charge or current that is present in the field. ...
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0answers
12 views

Why does the 180°-pulse in mrt not sync all phases like the 90°-pulse does?

As far as i understand, in mrt with the constant field B0 pointing in the z-direction, the 90°-pulse "screws" some of the relaxed spins, so that the expectation value of their magnetic moment rotates ...
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1answer
21 views

Computing energy loss for a hysteresis curve

Let a hysteresis loop be as shown in the figure, with $B_0$ the applied external field due to a current $I$ in a toroid, and $B_M$ the additional field due to the ferromagnetic material. Hence we ...
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1answer
17 views

How can DC-magnetic fields be produced with the aid of currents?

How can DC-magnetic fields be produced with the aid of currents? What's a possible theoretical explanation for this, and how does one achieve this in the real world? What are the maximum fields that ...
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1answer
31 views

Does the direction of the magnetic field inside a solenoid depends on the direction which it is turned?

Today trying to explain some magnetic stuff, just came across with a simple (at least seems) question. My question is brief: does the direction of the magnetic field inside a solenoid depends on the ...
2
votes
2answers
55 views

Finding net magnetic and electric force on charged particle [closed]

This is from my textbook, it is not an assigned problem, but I want to understand. It says: Consider the situation in the figure, in which there is a uniform electric field in the x direction ...
0
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1answer
23 views

Induced Current & Lenz's Law - 2 Circular Loops with same direction of current

I'm new to the wonderful world of physics, and I'm really confused about magnetism and induced currents. Let's say we have 2 circular closed loops that each carry a current $I$ clockwise and the ...
0
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1answer
26 views

There is some attempt to build a magnetic flywheel (reservoir of motion)

We know how flywheel works! There is some attempt to substitute the flywheel-friction mechanism for some magnetic torque ? Exist some mechanism that uses thermal cycle of gases for generate magnetic ...
0
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1answer
18 views

Average induction voltage

I've got a basic question on the method of computing the average induction voltage. Here is the task: A conductor loop with the area $A_1 = 50\text{cm}^2$ in a magnetic field with the flux density of ...
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1answer
14 views

Diamagnetism Experiment

I need to do a diamagnetism experiment but I don't have quite a knowledge about magnetism. First, I don't know which parameter I need to look to chose right neodymium magnets for diamagnetic effect. ...
2
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0answers
16 views

Where can I find actual data for the hysteresis of a magnetic material?

When a magnet is exposed to an external magnetic field it can be further magnetized or demagnetized. This amount can be found by looking at the hysteresis curve for that magnet. I do not have the ...
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3answers
58 views

Mathematical formula for hysteresis [closed]

For my final year project, I need to design a lab to generate a hysteresis loop. But I have no idea how to do it. Is there any mathematical function or any code or any article which would help me to ...
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1answer
28 views

Finding the vector potential of an infinite cyclinder with uniform surface current

This is the second part of a problem in Griffith's "Introduction to Electrodynamics 4th Edition" (problem 6.16). The first part was to find the magnetic field inside a coaxial cable (2 concentric ...
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1answer
126 views

What is a magnetic field [closed]

What exactly is the magnetic field? I know what it does, but I want to know what it's made of at microscopic level, and how it gets its shape. By comparison with the electrostatic field, which is ...
0
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1answer
26 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 ...
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2answers
120 views

The relationship between light and magnetic fields

I have two questions. Does light have a magnetic field? If not, can it be affected by other magnetic fields?
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1answer
54 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 ...
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3answers
57 views

Where is the energy stored in an inductor?

In an inductor, Most text books say that the $(1/2)Li^2$ is stored in the magnetic field. But is there another way to explain this? In a capacitor I understand that all the energy that the battery ...
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1answer
26 views

Wireless energy flow through earths magnetic field

Seeing that technologies such as that developed by WItricity are based on magnetic fields, is it possible to transfer electricity that way through earths magnetic field?
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0answers
52 views

Why do we define the magnetic field around a conducting rod as concentric instead of radial?

Why is it that we define the magnetic field around a conducting rod as concentric instead of being radially outwards? Ok, we know from the Lorentz force law, that the magnetic force is the cross ...
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0answers
46 views

Ed Leedskalnin's “Perpetual Motion Holder” (PMH)

Edward Leedskalnin (Coral Castle) describes a perpetual motion holder in his writings. I've built one and pretty much know how it works (I think). It is NOT a perpetual motion device by any means, ...
2
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2answers
128 views

How can a magnetic field accelerate particles if it cannot do work?

A varying magnetic field can accelerate charge particles, but it is said that a magnetic field can't do any work so it should not be able to speed up charged particles, right? How is this apparent ...
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0answers
16 views

electron trajectory in Bfield with energy kick at midpoint

So I wanted to get some second opinions on this situation I have thinking about.Lets say an electron enters, normally, a section of bfield that is perpendicular to its motion such that the electron ...
0
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2answers
105 views

Derivation of Faraday's law using Lorentz force?

For a stationary loop of wire with a time varying magnetic field $\vec{B}(t)$ through it. Is it possible to derive Faraday's law, using only the Lorentz force $$\vec{F}=q \vec v\times \vec B \tag ...
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0answers
26 views

Defining a gauge field for an anisotropic material under strain

I have a Hamiltonian for a system which is somewhat analogous to graphene but with additional degrees of freedom. The Hamiltonian is $H=\sum_q \Psi^\dagger \mathcal{H}\Psi$ where ...
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0answers
13 views

How will a single particle move in a curved magnetic field

How will a single iron powder move around the middle of a bar magnet, that is, when the force line is curved? I couldn't figure it out neither quantitatively nor qualitatively since the direction of ...
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1answer
27 views

Flux linkage of 2 coils in series

I have a question from magnetic circuits. I am an engineering student, therefore I will neglect some minor errors. There is a simple magnetic circuit with 2 coils ($C_1$ & $C_2$), with $N_1$ ...
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0answers
43 views

If we put diamagnetic material under strong electromagnet.Would the opposing magnetic fields strong enough to attract ferromagnetic materials?

Suppose we put a diamagnetic material (such as Bismuth or Pyrolytic Carbon) under a strong magnet (see image below). It would create opposing magnetic fields. Would the opposing magnetic field be ...