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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Expanding the Magnetic field?

A magnetic field $B$ can apply a force $X$ on a ferromagnet when there is no gap to separate them, $r$ = 0. When that gap ($r$) is increased to 3 cm, the force drops to zero. How can that be solved? ...
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1answer
64 views

What is the Significance of Magetic Field Energy Density?

If we consider electrostatic field energy density for an electrical field then by analysis we find that it is the representation of the total electrostatic potential energy of the considered ...
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1answer
91 views

Faraday's law question: wire falling over two rails

I'm having trouble with this problem. The picture shows a wire of mass m and length l which slides on two rails, with certain angle with respect to the horizontal.The whole circuit has a resistance R ...
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1answer
84 views

What determines the magnitude of force of an electromagnet?

Let's assume that there is an electromagnet with $B = 1 Tesla$ , what is the magnitude of the force it could generate on other dipoles equal to it's surface area? Can the magnitude of force (in ...
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0answers
421 views

Calculating the electro magnetic field strength needed to repel a permanent magnet

I have a design where a permanent magnet is placed on top of an electromagnet. When the electromagnet is powered off, the permanent magnet is attracted to the iron core of the electromagnet. When the ...
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0answers
159 views

Explanation for the physics behind magnetic monopoles?

Ok so I am looking for a simple explanation of how the process is done from the information I could access and the knowledge I was allowed I have the idea that it is a matter of quantum physics and ...
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2answers
523 views

Manganese has more unpaired electrons than Iron so why is Iron ferromagnetic Manganese paramagnetic?

Manganese has five unpaired electrons, but Iron has four, then why is Iron ferromagnetic and Manganese paramagnetic? What's that property I'm missing?
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2answers
5k views

What is the difference between an electric and a magnetic field? [closed]

This question is a consequence of another question of mine which is about spin. Here is my spin question. What is the difference between these two fields? How do they occur? Am I right if I say that ...
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1answer
310 views

Magnetic field of a solenoid at the poles?

It's known that at the center of an electromagnet/solenoid the magnetic field $B$ is strongest there. At the pole/edge of the solenoid/ or electromagnet is the magnetic field $B$ strong? Let's assume ...
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0answers
39 views

Would a $50\: \mathrm{Hz}$ spinning magnetic plate in front of a human generate harmful current?

We know that spinning magnetic plate will generate current inside any wire. so if we stand before 50Hz spinning magnetic plate, then, does that 50Hz spinning magnetic plate in front of us (human body ...
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2answers
228 views

What is the difference between diamagnetism and superconductivity?

Basically, What is the difference diamagnetism and superconductivity? As far as I understand, diamagnetism comes from the fact, that all electrons in a solid, when exerted by an external magnetic ...
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4answers
194 views

Why doesn't the magnetic field of a coil “cancel out”?

In a coil, we can see that the current moves right, then left, then right, then left, and so on as it travels down the coil. According to the right-hand grip rule, isn't the magnetic field going in ...
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1answer
644 views

What force particle mediates electric fields and magnetic fields?

The force carrier for magnetic fields and electric fields are supposedly photons. I don't get it: 1) Wouldn't that mean that a charged particle (e.g. an electron or even a polarized H2O molecule) ...
3
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2answers
61 views

why the shape or size of Magnetosphere is different both side?

Two days ago, I watched a documentary about solar flares, and how Magnetosphere protect us from that to earth. I was able to understand most of it, but I'm still curious to know why the ...
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2answers
100 views

Why is B always not 0

I discovered that while applying Ampere's law, For a solenoid.. B inside is calculated. But outside we say the loop encloses no net current or hence there should not be any field.. Let's say for ...
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1answer
83 views

Will magnetic field lines change when a magnet gets closer to other magnets?

As many books tells that the magnetic field can be illustrated by a bunch of field lines, which start from one pole and end up at the other. If I have a strong uniform field with field lines along ...
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3answers
1k views

Reducing Eddy current losses

Eddy currents are setup in any metallic block which is in the vicinity of changing magnetic fluxes. These primarily cause heat losses, and in certain cases causes damping of the relative motion ...
2
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2answers
117 views

Does the magnetic field lie in the Wave-Particle duality?

There is Wave–particle duality. According to this theory, light is a wave and a particle at once. What about magnetic field? Can it be so, that it is also a wave and particle, but this particle has ...
2
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1answer
60 views

Separating the convective and the inductive electric field

My question is basically this, if I am only able to measure the total electric field and the magnetic field at a few discrete points in space and time, is it possible to separate the convective and ...
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1answer
54 views

Magnetic field exclusion and retention in superconductors

I'm studying the behaviour of superconductors in different cases, and I can't understand this. We have a superconducting cylinder with a coaxial hole inside (vacuum). When the cylinder is cooled ...
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0answers
52 views

Graph of Lorentz force in function of angle between v and B-field?

I need to draw a graph of the magnitude of the Lorentz force in function of the angle between the velocity and B. Am i right in supposing this will be a sine wave?
2
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1answer
125 views

Contradicting forces on a circular loop under current in magnetic field?

I have the following general conceptual concern. Think of a thin conducting loop of radius $R$ placed in the $x$-$y$-plane at $z=0$. There is a homogeneous current density $\vec{j}$ running through ...
9
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1answer
235 views

Can a compass be used in a submarine?

This question is motivated by several "myths" I have heard recently - I want to know if there is a problem with using a compass inside a submarine. I can see two different issues, so I'm wondering if ...
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1answer
98 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
55 views

Energy of electron accelerated by a magnet

In the YouTube video Monster magnet meets computer, the south pole of a 1 T (roughly) neodymium magnet is held in front of a CRT. Assuming the CRT produces electrons of 30 keV, and that the screen is ...
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0answers
24 views

Ferrous object detection-ability dependent on size and depth?

The question came about when I was using a gradiometer to detect ferrous metal. From the datasheet they recommend a certain depth range for a larger ferrous metal buried in the ground. My question ...
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0answers
144 views

Why the letter $B$ for magnetic fields? [closed]

Is there a reason behind the usage of this letter to represent magnetic fields, or is it a randomly made choice?
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1answer
76 views

Does the Lorentz force applied to a current carring wire by a magnetic field act in the negative or positive direction of the right hand rule?

If I say that I am calculating the Lorentz force $F$ applied to a wire carrying a current $i$ at a point $P$ in a magnetic field $B$, would the actual force be opposite of that given by the right hand ...
2
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1answer
103 views

How would you explain the cause of earths magnetism to an 8th grade student

What would happen if I freely suspend a bar magnet at north pole, will it become vertical? I am the 8th grade kid.What would happen if earth brakes into two pieces,will there be new north and south ...
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2answers
241 views

Motion of charge in magnetic field with drag force [closed]

Say you have a charged particle in a region that contains a fluid that will produce a drag force that goes as $F=-kv$ where $v$ is the speed and $k$ is some constant. The region also contains a ...
3
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2answers
899 views

Do two magnets stacked on top of each other repel/attract stronger than just one magnet?

In designing a switch, I made it such that it "springs" back via two neodymium magnets (one in button repelling one in switch). I've found the magnets are too weak and don't spring back. I've resorted ...
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1answer
212 views

How this linear Motor Shaft works?

I am trying to understand how this linear motor works: You can see a video here for more details. From what I know each permanent magnet consist a North and South poles so for a cylindrical magnet ...
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2answers
70 views

Coronal Mass Ejection and its effect on Earth's Orbit

Do CMEs (Coronal Mass Ejections) have an effect on Earth's Orbit around the sun? Given the the Earth and Sun are essentially two large magnets, one in orbit around the other. If so, how much of an ...
5
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1answer
156 views

How can steel shavings get magnetized while hole tapping?

I was tapping a hole yesterday with my uncle into a piece of soft steel. (A tap cuts threads on the inside of a hole, to accept a machine screw or bolt.) The tap was NOT magnetic! As I finished boring ...
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1answer
208 views

Does greater number of lines of force around the magnet imply greater magnetic field strength around it?

If we sprinkle iron fillings on a sheet of glass placed over a short bar magnet. The arrangement of iron fillings will be similar to the one shown above. Why do some of the iron fillings ...
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0answers
30 views

Opposite field's acting on a soft ferromagnetic material

To external fields(H, - H) not equal to each other are acting on that material. Based on the hysteresis loop what would be the result? The hysteresis area of that materials is very narrow(i.e easy to ...
3
votes
1answer
601 views

Axial forces on a solenoid windings

I understand that the windings in a solenoid experience a Lorentz force $\mathbf{f} = \mathbf{J} \times \mathbf{B}$, which tend to cause an outward pressure where $\mathbf{B}$ is directed along the ...
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2answers
901 views

1 Tesla electromagnet?

Is it possible to create a powerful electromagnet at home? With use of a ferromagnet it seems so... Using the following formula: $B(Tesla)= k\mu_0nI$. I understand some ferromagnet's like iron could ...
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4answers
218 views

Is voltage important when creating a magnetic field?

Would a DC circuit that has a high current and low voltage have a powerful magnetic field? I'm trying to create a powerful solenoid. In order to create a powerful magnetic field, I'm focusing more on ...
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0answers
47 views

Help in understand Magnetostatic Energy

$$E_{\mathrm{ms}} = \frac{1}{2}\mu_0 \int_V \mathbf{M} \cdot \mathbf{H}_{\mathrm{ms}} d^3 r$$ I can't understand this formula, what is the magnetostatic stored potential energy?! What does it show? ...
5
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1answer
210 views

Why Inox Steel doesn't interact with magnets?

My dad has a HUGE magnet on his workshop. I love magnets, and when I saw it, I asked him what it was for. His reply was: "I don't know why, but inox steel bolts don't get attracted to it, so I use ...
2
votes
1answer
393 views

How does repulsion and attraction of a magnet work?

How does repulsion and attraction of a magnet work? I have a hypothesis. We all know that repulsion works when people throw balls at each other. This is used as an analogy of how virtual particles ...
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2answers
404 views

Why is a paramagnetic material attracted into a magnetic field?

I want to start by saying I've seen this topic: Attraction and repulsion of Magnetic materials and its supposed duplicates and it hasn't helped me very much. In the book Introduction to ...
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0answers
43 views

Which is more energy efficient: optical demagnetization or heating beyond $T_c$,

What is considered more energy efficient? Current research show that the amount of energy used for powering a laser to demagnetize a material is quite small. However, the demagnetization is very ...
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0answers
90 views

Calculating repulsion due to eddy currents?

I have a conductive particle moving at a known speed through changing magnetic field (Permanent magnets attached to a rotating drum alternating north/south). These particles will have induced eddy ...
2
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1answer
83 views

$\hat{\imath}$ component of force exerted on an electron by a magnetic field?

The magnetic field over a certain range is given by $\vec{B} = B_x\hat{\imath} + B_y\hat{\jmath}$, where $B_x= 4\: \mathrm{T}$ and $B_y= 2\: \mathrm{T}$. An electron moves into the field with a ...
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0answers
43 views

Formation of magnetic field in an inductor

I can't really imagine the way the magnetic field would be created due to electron flow in an inductor. We say that in a straight current carrying conductor the magnetic field follows the thumb rule. ...
3
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1answer
282 views

Detecting EM radiation using android app

I wrote a simple android app that shows the magnetic field(using the magnetic field sensor in the phone) in the current location. When I place a two inch steel screw on the top of the phone (which ...
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0answers
63 views

Lasers can demagnetize ferromagnets?

How is it possible to demagnetize a magnet with a laser? Source: http://www.helmholtz-berlin.de/pubbin/news_seite?nid=13657&sprache=en&typoid And the paper: ...
5
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2answers
91 views

In a strong field, how long would it take for domains to align?

How fast is the rate of "switch" for the domains to align with an exterior field? Possibly in milliseconds? I assume it won't take much time since domains are very small, and they only turn from a ...