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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How can I approximate calculate the magnetic force between electromagnets?

I try to find an approximate amount of force exerted between two electro magnets. The below site could've helped me but the problem is that the below just talks about the number of coil turns and so ...
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1answer
54 views

Magnetic field induce photons?

So silly question, can a oscillating magnetic field excite electrons around atoms such that they produce photons (In other words can an applied magnetic field increase the energy level of electrons ...
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1answer
46 views

Eddy currents in a superconductor

Just had a lesson we just had our teacher introduced the concept of eddy currents, and showed us how a magnet moves slowly through a metal tube due to the opposite generated magnetic field. If you ...
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1answer
26 views

Net magnetic field in a loop

The Ampere's law states that the net magnetic field in a loop is proportional only to the current inside the loop. So if we calculate the net magnetic field in figure 1 and figure 2 we would obtain ...
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0answers
19 views

Magnetic susceptibility anisotropy

I have some problems in understanding magnetic susceptibility anisotropy. I know that magnetic susceptibility can be described via a rank 2 symmetric tensor so the magnetization induced in a sample is ...
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1answer
28 views

Finding the electric field in a bar moving through a magnetic field [closed]

In this diagram: I'm supposed to find the electric field through the bar at equilibrium. I know that at equilibrium, the accumulated positive charge on the bottom of the bar results in a field that ...
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0answers
20 views

Precession or projection?

A spin of 1/2 in a magnetic field is known to rotate around the direction of the field. But then it is also stated that it must be projected spin up or down. Is this simultaneous or happens after ...
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0answers
35 views

RL vs RLC circuit magnetic field

If I want to create an alternating magnetic field using an inductor, what difference would it make to use a series RL or a series RLC circuit ? How will the presence of a capacitor affect the magnetic ...
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1answer
66 views

Magnetic field of a solenoid vs magnetic circuit

The magnetic field in the middle of a solenoid is : $$B = \frac{\mu_0 N I}{L}$$ where L is the length of the solenoid The magnetic field in the air gap of a magnetic circuit with constant cross ...
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2answers
33 views

Direction of magnetic field

How did we know that the direction of magnetic field is from north to south and not the opposite? For example, we may use iron filings, and they will take the shape of the magnetic field, but how we ...
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1answer
45 views

Biot–Savart law for a finite wire or the center of a square coil

I need to find the magnetic field inside the center square of a coil (I think this is the name, I'm translating, but if not, I'm talking about a loop of a wire, just 1 turn) of side $50cm$. So, I ...
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1answer
82 views

What is exact difference between gravitational force and magnetic force? [closed]

I've read that gravitational force is due to mass only and magnetic field is due to moving charged particles. But my question is: what are other difference between them? Can we set up a small ...
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0answers
24 views

Wire with current in magnetic field $\vec{B}$has force $\vec{F_1}$. When rotated, $\vec{F_2}$. Find $B$ [closed]

I have the following question: In a wire with $10cm$ there is a current $4A$ going 'upwards' in the $z$ axis. The force over this field, under a constant magnetic field $\vec{B}$ is $F = -0.2\vec{i} +...
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0answers
33 views

How to calculate maximum magnetic flux density of magnet?

I have some magnets of which I need to calculate the maximum magnetic flux density B. I don't have any dedicated setup to measure the value. Is there any way in which I can measure it by relating it ...
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1answer
15 views

Which way is the magnetic field headed? [closed]

Question Is the magnetic field directed into the page or out of the page? I am using this right hand rule --> RHR So anyhow, my index finger is pointing downwards, and since the magnetic force is ...
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3answers
58 views

Right Hand Rule on the magnetic field not working? [closed]

Background: The magnetic field is going into the page and the velocity of the particle is going towards the right. What is the sign of the particle? I keep getting this wrong. The magnetic field is ...
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1answer
65 views

Motion of an electron in a magnetic and electric field [closed]

I have this problem where i should find the direction and magnitude of the electric and the magnetic force on the electron. E = 1000 N/C B = 2,5 T v = 500 m/s ...
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0answers
44 views

Lab experiment: hysteresis disappears, reappears and then disappears again. How?

In my college laboratory we were assigned an experiment to measure the hysteresis curves of a certain ferromagnetic material at different temperatures. Sounds simple, right? Well, the block of Monel ...
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1answer
38 views

Does the electrons in Stern-Gerlach aplliance change their energies and how?

When an electron goes thru a Stern-Gerlach appliance it changes its spin projection. Then there must be a change of energy content of the electron due to this event. But it is also known that magnetic ...
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1answer
26 views

How to find the force of a magnetic field, resolving the components?

So, in answering this question the book resolves the components of the Force vector in this manner; $\mathrm dF_x= \mathrm dF \sin \theta$ $\mathrm dF_y= \mathrm dF \cos \theta$. And then, it ...
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1answer
27 views

Approximating magnetic field at center of current loop by solenoid of 1 turn

It's well known that by application of biot-savart law, the magnetic field at the center of a loop of current is $\frac{\mu_0 I}{2r}$. Now when we consider a solenoid, isn't the resulting magnetic ...
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0answers
37 views

Lorentz sphere correction

I am studying Lorentz surface correction for magnetic fields. I know that if we consider a uniform distribution of magnetization, the field can be computed as three contribution: $H+H'+H''$ where $H$ ...
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3answers
59 views

Ampere's law for a rectangular plate?

If a conductive wire was carrying current $I$, it would create a magnetic field: $$B=\frac{\mu_0I}{2\pi r}$$ However, if it's not a wire, but instead a plate how would the expression change/adjust ...
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0answers
21 views

Current density to find the magnetic field and Lorentz force?

Problems where there is a copper wire of a large diameter, the solution would tend to use current density $J$ to accurately compute the magnetic field $B$ at a distance. Why so? Why not simply use $I$?...
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1answer
46 views

Ampere's law and Stokes' Theorem for current density

In both Griffiths and Jackson, Ampere's Law (or conversely the curl of the magnetic field) is derived by applying Stokes' Theorem to the surface integral of the current density J. The argument relies ...
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5answers
503 views

Can one deduce absolute motion through magnetism? [closed]

I am trying to understand forces in relativity: Suppose there are two electrons A , B travelling side by side at 1 cm distance at .99 c (in space or at lHC, ignoring all other factors). I know that ...
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1answer
43 views

electron in magnetic and electric field

I have this problem where i should find the direction and magnitude of the electric and the magnetic force on the electron. And then I'm supposed to find the direction and magnitude of the ...
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1answer
45 views

Solenoid vs coil of wire

This may sound pretty basic, but: I'm studying for my AP Physics exam, and I am confused. Apparently, the formula for the magnetic field in the center of a loop of wire with $n$ turns is: $B=\frac{\...
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0answers
27 views

Magnetic force on an iron nail

Work done by a magnetic force is zero but the why iron nails are attracted towards a magnet. The fly towards a magnet so the gain K>E i.e work has been done on them. I know its not actually the ...
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0answers
19 views

Can a diamagnetic levitator levitate non-permanent ferromagnetic materials?

I am building a diamagnetic levitator that will eventually levitate a small neodymium cube. However, is it also possible for an iron cube to be levitated as well? I know that diamagnetic materials ...
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1answer
35 views

Is it possible to levitate large objects through diamagnetic levitation?

I am currently building a diamagnetic levitator with a strong neodymium magnet, two slabs of bismuth (a diamagnetic material), and a small neodymium cube to levitate. However, I was wondering if it ...
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2answers
78 views

how do we actually count the number of magnetic field lines and what does the gap between those lines describe?

on the internet,(http://nuclearpowertraining.tpub.com/h1011v1/css/h1011v1_53.htm), there is a statment which says that 1 Wb is $1\times 10^{8}$ magnetic field lines. My question is, How do we count ...
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1answer
73 views

Questions about Magnetic field [duplicate]

I have two questions about Magnetic Field. Given a particle with mass m, charge q and uniform B field. B is going into the page, and particle is moving to the right Like this. The textbook says ...
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1answer
104 views

High Level Understanding Q: What *is* a magnetic/electric field?

Note: I have seen this question -> (What is a magnetic field) and would still like some clarification. I have also seen https://www.youtube.com/watch?v=hFAOXdXZ5TM and https://www.youtube.com/watch?...
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0answers
21 views

Explanation of absorption from Bloch Equation

Suppose in a magnetic resonance experiment the microwave/rf field is applied in x-direction.How to say that the component of magnetization which is out of phase with the microwave magnetic field leads ...
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0answers
29 views

How to calculate pull force of a solenoid with permanent magnet plunger (NdFeB)?

The solenoid is air core. If we use permanent magnet like NdFeB as a plunger, how to calculate the pull/push force of the solenoid with plunger?
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0answers
14 views

Why does a 2-sided propagating EM wave become 1-sided if B is made proportional to E?

If you simulate the propagation of an electromagnetic wave in 1D free space (no charges or currents) with initial conditions of $E\neq0$ and $B=0$, and you look at a movie of $E$ vs time, then after ...
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0answers
42 views

use FEMM to simulate electric field for a magnet inside a coil

I'm trying to simulate a magnet inside of a coil of wire, with and without current running through the wire. I'm using the free FEMM software to try to simulate this, but I don't think i'm setting ...
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0answers
80 views

Is magnetic field changing over the distance?

If we take ONE separate magnet, with lines of the magnetic field coming out of north and going into the south. 1) Does magnetic field change along any of those lines? [ 2) If no (that is what I ...
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0answers
34 views

Magnetic field interaction energy term

I am trying to derive the Ginzburg-Landau free energy for superconductors, and I follow most of it apart from the introduction on the term containing the magnetic field. This is the bit I don't ...
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0answers
28 views

Net magnetic field & magnetization on a ferromagnetic material

A ferromagnetic materiel is saturated by an exterior magnetic field like so: Where $B_1$ is a uniform magnetic field. Then after some time $t$ another magnetic field $B_2$ is introduced as well, ...
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0answers
35 views

What metal can be used as electromagnet core to attract a permanent magnet?

ok. Here are the requirements: 1.The core should not be attracted to permanent magnet when idle(like stainless steel), 2.Should act as electromagnet core with better permeability(like iron). Is ...
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1answer
45 views

Why does a magnet loose magnetic strength when heated?

Magnet manufacturing companies, for example Dexter Magnetic Technologies do not hesitate to explain the effects of heat upon magnets - citing how it degenerates the magnetic properties with levels of ...
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2answers
57 views

The direction of magnetic field- right hand rule

My question is, why is the magnetic force going the same way as the fingers, why not the other way. What causes the magnetic field to choose a direction if everything is symetrical
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1answer
36 views

Magnetic field and magnetic domains

I have a confusion regarding how magnetic field propagate in a medium (ferromagnets or air etc..). It is knows when a ferromagnet is exposed to an external magnetic field, the magnetic domain of the ...
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1answer
32 views

The MRI signal: why do we consider the phase in the MRI signal

I am trying to understand the imaging principles behind MRI and I was looking at some lecture slides found here Specifically, I am looking at slide 41 where we look at some of the equations regarding ...
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0answers
40 views

Attraction between electromagnet and a permanent magnet - at which point is the force the strongest?

You have an air-core inductor with current applied, so that the magnet in the picture will be attracted to it. At what position will the force between the two be the strongest and at which the weakest?...
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0answers
28 views

Would a spinning carbon steel (high magnetic permeability) sphere become magnetized?

Would a spinning carbon steel (high magnetic permeability) sphere "falling" through Earth's magnetic field become magnetized? Would a spinning, evenly charged sphere generate a magnetic field?
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1answer
44 views

What is the reason behind the shape of the magnetic field lines in a circular loop?

Sorry if this question is stupid, but I really need to understand this. I read that in a straight simple wire, the magnetic field lines are concentric about the wire, and the circles become larger as ...
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2answers
46 views

Electromagnetism on a compass [closed]

A current $2\ \mathrm A$ flows in a vertical wire. The value of the horizontal component of earths magnetic field in the region is $2*10^{-5}\ \mathrm T$. A small compass is placed $5\ \mathrm{cm}$ ...