The magnetic-fields tag has no wiki summary.
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Mechanism by which electric and magnetic fields interrelate
I read that force due to electric field on some particle in one reference frame can exhibit itself as force due to magnetic field in some other reference frame and that electric and magnetic fields ...
6
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4answers
294 views
How do permanent magnets manage to focus field on one side?
The actuator of a hard drive head consists of two very strong neodymium magnets, with an electromagnetic coil between them. If you take that apart, the magnets attract each other very strongly. ...
6
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1answer
56 views
Is it possible to determine astronomically/astrophysically whether other planets have ever encountered polarity reversal?
We know of geomagnetic flip in Earth's history by studying geologic data. Given other planets in the system also possess a magnetic field leads to the assumption that such polarity reversal may not be ...
6
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1answer
71 views
Does a celestial system exhibit a collective magnetic field?
Sol exhibits a magnetic field, most of the planets in orbit around Sol exhibit a magnetic field - strong and weak both.
Does the solar system as a whole exhibit a magnetic field?
Does the paradigm ...
5
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1answer
50 views
Do all known planets and moons have magnetic field?
In this Wikipedia article it is stated, that magnetic field of Earth is caused by currents in her core. The same origin is for Jupiter magnetic field.
For Moon (article) there is a magnetic field, ...
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2answers
163 views
Effects of a very large magnetic field on the human body
Ever since reading about the NHMFL I have always wondered about this and asked several people without getting a good satisfactory answer. My question is, considering the simplest case let's say a ...
5
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1answer
134 views
Why doe we not get a shock on induction cooker?
In induction cooking, eddy currents in cook-pot cause heat to be produced. But why do we not get a shock?
Also, why is it that current is converted to heat while it has a good conductor(say, steel) ...
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2answers
105 views
Cancel out Earth's Magnetic field
Is there any tools except helmholtz coil to cancel out earth's magnetic field to calibrate magnetometers in practice.
4
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1answer
186 views
If the Moon had gravity as good as the Earth and a magnetic field could it have supported life?
If the Moon had gravity as good as Earth and a magnetic field could it have supported life? Because if the Moon had gravity, it could have retained water more than is present today on the surface.
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2answers
71 views
Can a current carrying loop or wire produces no magnetic field?
A current carrying wire produces magnetic field around it. We can find the direction by Fleming's Right hand rule. We know change in electric filed produces magnetic field and change on magnetic field ...
4
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1answer
107 views
Linear dependence of magnetic potential on current density
I'm a mathematician learning physics to provide some background for my mathematical work (especially pde's!). I have been reading through Jackson's Classical Electrodynamics (3rd edition), and I was ...
4
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1answer
289 views
Physical meaning of magnetic length
What is the physical meaning of magnetic length $\ell_B=\frac{\hbar c}{e B}$ in 2D electron system under magnetic field? When $\ell_B \longrightarrow a$, where $a$ is the lattice constant, does that ...
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3answers
183 views
Induction cooker + superconductive pot
What will happen if I put a super-conductive object on an induction cooker, and turn the cooker on?
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4answers
104 views
Why in $F = iLB$, $L$ is a vector but $i$ is not?
I learned $F = iLB$ recently. However, I don't understand why $L$ is marked as a vector but $i$ is not.
For a normal rod, how should I define the direction of length vector $L$? And if I reverse the ...
2
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1answer
53 views
What is the Earth's magnetic field in space?
I have looked around a bit, but haven't found a simple answer. At an altitude between 100-1000 km,
Is the magnetic field B still around $\sim 10^{-5}\ T$? Is there a simple equation that would provide ...
2
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1answer
82 views
Liquid benzene magnetic susceptibility
In a solid state physics problem, I'm asked to make a rough estimate of the contribution to the diamagnetic susceptibility of the outer electron of each carbon atom. The wavefunction of these ...
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2answers
52 views
Would a magnetic rod through Mars shield it from solar wind?
Would a magnetic rod going all the way through Mars shield it from solar wind?
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1answer
397 views
Magnetic Fields created by Current-Carrying Wires
The drawing shows two perpendicular, long, straight wires, both of which lie in the plane of the paper. The current in each of the wires is I = 5.6 A. What is the force and torque acting on each wire ...
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2answers
69 views
Charged quantum particle in a magnetic field - choosing a different gauge leads to different wavefunctions
Consider a charged quantum particle confined to the $xy$ plane, subject to a magnetic field $\mathbf{B}=B\hat{z}$.
The Hamiltonian is:
$$ H = \frac{1}{2m} \left( \mathbf{p} - \frac{e ...
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2answers
2k views
Why does electricity flowing through a copper coil generate a magnetic field?
Can some one please explain to me why electricity flowing though a copper coil generates a magnetic field or where I could possibly find that information? Are there other materials that produce a ...
2
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1answer
66 views
Difference between electromagnetic radiation (EMR) and Electromagnetic Field?
I'm a freshly graduated electrical engineer. One course that I really struggled with was Field Theory, because it was a lovely assortment of vector calculus and things that were explained to me well ...
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2answers
129 views
Should I use Coulombs law when magnets attract/repel?
When magnets attract to each other or repel.
Should I use Coulombs law? If not, why not?
Some would say that I shouldn't because: "Coulomb's law deals with static charges and force due to them. ...
2
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1answer
70 views
Magnetic field line length
If I had a magnetic bar in space that was 2cm wide and 2cm high and was one Earth diameter long and had the same magnetic strength as the Earth, would the distribution of field lines be the same ...
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3answers
667 views
How to make a small tokamak?
$\require{mhchem}$I made a fusor once, like the easy science project: deuterium-deuterium ones, but they're really inefficient. I was wondering if it would be possible to make a small tokamak; not one ...
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0answers
31 views
Magnetic Field versus Line Charge
Isn't a magnetic field basically an electric field originating from a line charge, but as seen in a boosted frame? I mean, that's where the relativistic explanation comes from right?
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0answers
34 views
Is it possible to measure outside magnetic field from inside a car?
I know that I can detect a vehicle by using magnetic field. I can see obviously difference in signal when a vehicle pass. But I don't see that when measuring in a car.
Is it possible to measure ...
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4answers
59 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
68 views
Purcell and the Magnetic Field
When showing that the magnetic field derived from the curl being proportional to current and the divergence being zero is unique, Purcell says that at some sufficiently remote enclosing boundary the ...
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1answer
52 views
What geological properties of the earth could we deduce by measuring magnetic field strength and direction?
I wonder if it is of any use for a geophysicist, if we measure the magnetic field strength and direction of the earth.
Could we make valid statements about the composition of the the earth, earth ...
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1answer
51 views
What causes the collapse of a Magnetic Field?
It's theorized that Mars once had a magnetic field which collapsed at some point.
There's also lots of speculation that a similar process will eventually happen to Earth. More recently has been the ...
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1answer
65 views
Movement of the particle in a magnetic field
This is the numerical question.
A particle having a mass of 0.05 mg carries a charge of $5\times10^{-6}C$. The particle is given an initial horizontal velocity of 5000 m/s, what is the magnitude ...
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1answer
115 views
Do magnets lose their magnetism/force when they attract/repel each other?
So yea, if two magnets attract/repel multiple times(A LOT) will they lose their magnetism? If they don't break during the whole process?
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1answer
113 views
Is my electric power cord creating magnetic field when coiled?
Simple question. But I was wondering, does my mac power cord create a magnetic field when its all coiled?
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1answer
176 views
Basic magnet through a copper coil experiment - What if poles were rotated 90 degress
I was wondering what voltage or current, if any, would be produced if the basic magnet through a copper coil experiment had the poles rotated 90 degrees so north and south faced the top/bottom of the ...
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1answer
30 views
A simple electromotor?
I have to build a simple electromotor in the following way: I attach a permanent magnet to a battery, connect some metal supports to the terminals of the battery, and place a coil of wire on the ...
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1answer
50 views
B-field and Magnetic forces, speed of a particle
Let's say I have a particle moving perpendicular to a uniform magnetic field of magnitude $x \ T$, and it moves in circle with a fixed radius. How do I find the speed of this electron? Initially I ...
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1answer
410 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
73 views
Easy question about magnetism?
I have to build a simple electric motor by attaching a magnet to a battery, extending the terminals of the battery (with stiff wires so they could act as supports), and placing a coil of wire on top ...
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1answer
61 views
A good theoretical approximation for a magnetically damped pendulum
In a laboratory course we had to perform an experiment with a pendulum (just an iron weight on a wire) and play around for some time with its wire's length and so on.
This was quite boring and we ...
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0answers
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What name would you give to the method of approximating an arbitrary magnet with many smaller dipoles?
Let's say I had an arbitrarily shaped permanent magnet, with total magnetic moment $M_{0}$. Ways to calculate the magnetic field of this magnet include an analytic solution (if one exists), as well ...
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0answers
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Rosenberg-Coleman effect
I know only that it states some variations of the Sun's magnetic fields. What is the Rosenberg-Coleman effect specifically?
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1answer
109 views
Separation of solids from liquids using magnetic waves
Using magnetic forces, I want to separate solids from liquids in a solution as a centrifuge would do. Is there a way to hit a volume of liquid and get it to separate liquids and solids with heavy ...
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2answers
83 views
Difference between electrostatic and magnetic field [closed]
In this, F (the force set by the field) is perpendicular to the speed of the particle. In which case does F change the absolute value of V? Why or why not?
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1answer
88 views
How does a magnet work?
I'm having trouble understanding how a magnet (not the field that is generated as a result but the material itself) work. The particles are aligned in a specific direction to give rise to force but I ...
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2answers
118 views
Force on a bar magnet
A bar magnet is freely falling vertically inside a conducting ring placed in horizontal plane. Will it fall with an acceleration equal to g, less than g or greater than g?
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1answer
123 views
How to calculate the effect of the earth's magnetic field on a HZE particle?
I'm trying to calculate the protection provided by the earth's magnetic field from HZE particles to astronauts in low earth orbit, such as those on the ISS.
HZE particles are often quoted as a danger ...
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1answer
58 views
Magnetic Field and the Speed of Light
Is it just a historical choice that both magnetic field and the Lorentz force equation include the speed of light?
I figure that whoever wrote up the equations (in cgs!) could have put both factors ...
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1answer
54 views
If I have a rectangular loop moving through a magnetic field, which way will it go?
If I have a rectangular loop moving through a magnetic field, which way will it go?
A uniform magnetic field (say it's pointing into the page)
A square/rectangular loop of wire moving into the field ...
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1answer
112 views
Eddy current losses in electric steel by harmonics of a magnetic field
I am working on an model of a permanent magnet synchronous machine. Right now I am stuck with calculating the eddy current losses caused by the harmonics of the stator magnetic field in the electrical ...
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1answer
55 views
Possible to generate an electromagnetic field from moving an object through a magnetic field?
Is it possible to generate an electromagnetic field from a stationary rare earth magnet with a hole in it by passing an object through the hole?
By definition, a Lorentz Force is the force on a ...
