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 ...

learn more… | top users | synonyms

2
votes
2answers
155 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 ...
0
votes
1answer
38 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 ...
0
votes
0answers
36 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 ...
1
vote
1answer
27 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?
0
votes
0answers
6 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.
-2
votes
1answer
340 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, ...
0
votes
0answers
32 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 ...
1
vote
4answers
287 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. ...
0
votes
0answers
18 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 ...
0
votes
1answer
111 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 ...
0
votes
1answer
21 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 ...
1
vote
1answer
95 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
107 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
votes
1answer
92 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
votes
1answer
30 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
votes
1answer
20 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 ...
0
votes
1answer
27 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
votes
0answers
30 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 ...
1
vote
3answers
82 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 ...
0
votes
1answer
101 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 ...
-2
votes
1answer
152 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
votes
1answer
84 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 ...
2
votes
2answers
217 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?
0
votes
1answer
100 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 ...
0
votes
3answers
93 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 ...
-1
votes
1answer
36 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?
1
vote
0answers
58 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 ...
1
vote
0answers
171 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
votes
2answers
348 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 ...
0
votes
0answers
19 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 ...
1
vote
2answers
249 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 ...
0
votes
0answers
15 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 ...
1
vote
1answer
42 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 $N_1$ ...
0
votes
0answers
94 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 ...
3
votes
4answers
1k views

Magnetic force between two charged particles?

I know the gravitational force between two particles with masses $m_1$, $m_2$: $$ \vec{F} = \frac{Gm_1m_2}{|\vec{r}|^2} \hat{r} $$ And I know the electrical force between two particles with charges ...
0
votes
1answer
86 views

Given a Magnetic Field vector, what is the Electric Field, charge density, & current density?

I tried searching for this before having to ask, so please forgive me if I missed a previous question similar to mine. This is a Grad class, so I may be unnecessarily too careful in not assuming ...
0
votes
2answers
89 views

Divergence of vector potential

I was given the vector potential $$\vec A (\vec r) = - \vec a \times \nabla \frac{1}{r}$$ with a constant vector $\vec a$. Now, I found the $\vec B$ field which is I think $- \vec a \frac{2}{r^3}$, ...
0
votes
1answer
55 views

If a cube magnet were a die, how would it be numbered?

I have a number of cube-shaped magnets. If I start with 64 cubes all in one long chain and begin arbitrarily "folding over" groups of them so that I am left with a 4x4x4 cube, I rarely get the same ...
0
votes
2answers
89 views

What happens to electric field of a bar magnet?

Electromagtic waves say that Magnetic field and electric field exist orthogonal to each other. Also all electric field has some magnetic field and vice-versa (As I understand). In that case what is ...
1
vote
0answers
52 views

Why is no work done by magnetic forces in a uniform B and E field (perpendicular to one another)?

Say $B$ points in the $x$ direction, and $E$ points in the $z$ direction. Assuming a charged particle begins at rest at the origin, its motion will be a cycloid that progresses indefinitely in the ...
0
votes
2answers
438 views

How to demagnetize a magnet temporarily?

How to demagnetize a magnet temporarily? Is it possible making a permanent magnet demagnetize for a short span of time? Or at least long time but temporarily!
1
vote
0answers
23 views

Earth's magnetic effect on my magnet

My magnet seems to work independently of, and unaffected by, the Earth's magnetic field, yet the magnetic field of my magnet changes as I introduce some other similar magnets of varied sizes into its ...
0
votes
2answers
83 views

Why do we lose signal in elevators? [duplicate]

Whenever I am talking on my phone and walk into the elevator the call drops as soon as the doors close, and also the WiFi signal completely stops. Why does this happen? Note: I am asking this ...
1
vote
1answer
279 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 - ...
0
votes
1answer
59 views

Can we shield a certain region of space from magnetic field? [duplicate]

Recently I learnt about shielding a region of space from an electric filed. I wondered if the same can happen for magnetic field.
0
votes
0answers
53 views

BH Curve of NdFeB Magnet, Grade N50

Every magnet manufacturer provides his own BH-demagnetazation curve of the Neodymium Iron Boron (NdFeB) permanent magnet, grade N50, differently from other manufacturers. Is there a trusted ...
0
votes
0answers
19 views

Is there a way to detect acceleration of an object using a magnetic field readings (magnetometer)

I intend to design an application for Android which uses the accelerometer to detect the acceleration. However I'd also like to use the magnetometer to reduce the noise from accelerometer readings. My ...
0
votes
0answers
19 views

What causes a larger (longer) electrical arc when using a tesla coil

So, I really don't know much about this subject, if any at all, but I'd like to do a project on it. I've done some testing with my tesla coil and there appears to be a trend such that a larger ...
1
vote
0answers
18 views

What is an approximation for the B-field of a bar magnet?

I've found the following equation in this source: $$B_\text{N,S} = \frac{\mu m}{4\pi r_\text{N,S}^2}$$ Where $r$ is the distance of "one pole"? I do not get how this can be well defined. The effective ...
0
votes
0answers
15 views

Will diamagnetic behave as magnet to other magnets when placed in magnetic fields? [duplicate]

If we use magnetic field on diamagnetic.Will it behave as magnet? According to diamagnetic metals they create opposing magnetic field.Is that mean that diamagnetic become magnet itself? Will it ...