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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2answers
59 views

Why do all magnetic field of a bar magnet do not start and end only at pole?

Iam very confused that why not all field lines emanate out of a pole? Why few field lines emanate and in middle of a bar magnet as shown in the following figure:
0
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1answer
77 views

What is the direction of magnetic lines of force inside a bar magnet? [closed]

So basically , we all know the direction outside the magnet its from NORTH to SOUTH. but what i don't understand is that what is the direction inside is it the same ??
2
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2answers
21 views

Inductor circuit

Consider a inductor circuit with an inductor connected to a DC battery and a switch. Initially the switch is open. At time $t=0$ the switch is closed. What will happen to the inductor just after ...
0
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0answers
25 views

Stabilizing a shaft with only one electromagnet

I have recently come across Earnshaw's theorem in my research which states that it is not possible to stabilize an object using only static permanent magnets. I understand that and it makes sense to ...
2
votes
1answer
42 views

How to get speed of a train without using GPS

How can I measure instantaneous speed of a train in which I am travelling without using GPS/location services? The train can start underground or can start from ground level (where GPS is available) ...
1
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1answer
85 views

Creating a Magnetic Monopole through a torus [duplicate]

Could you create a magnet in shape of a hollow torus and magnetize it so that the interior is south and the exterior is north in order for it to act as a monopole? Is that possible? Thanks
0
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1answer
27 views

Does the magnetic flux spin in the same direction when the electric field is growing and collapsing?

I have three concentric iron pipes, stacked inside each other. It looks like a bulls-eye when viewed from above. To the innermost and outermost pipes I have connected a battery through a switch. ...
1
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1answer
19 views

Which conditions need to be fulfilled for a FODO cell to provide focusing in both planes?

I often come across the claim that a FODO cell can provide focusing in both planes so long as said cells are appropriately configured. I have never come across any elaboration of what this ...
1
vote
1answer
137 views

How does the electrons' magnetic dipole moment get influenced when electrons are moving through a magnetic field?

How does the electrons' magnetic dipole moment get influenced when electrons are moving through a magnetic field? How does the electrons' intrinsic spin influence the direction of the electrons' ...
1
vote
1answer
69 views

Magnetic Field in parallel plate capacitor [closed]

A parallel plate capacitor of area 60cm^2 and separation 3mm is charged initially at 90 micro coulomb. If the medium between the plates get slightly conducting and the plate loses charge initially at ...
0
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0answers
45 views

Magnetic monopole in arbitrary dimension

Assume we have D-dimensional space-time in spherical coordinates $(t, r, \theta_1, ..., \theta_k)$. We have Maxwell equations for $k$-form $F^{\alpha_1, ..., \alpha_k}$ $$\partial_{\mu} F^{\mu ...
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1answer
37 views

deflection of compass and rest position through Magnetic induction

I found a problem with a compass and a magnet, as diagrammed below. The needle of the compass was oscillating, but when a soft iron bar was placed in the "X" then the needle came to rest. Why did ...
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0answers
13 views

Force on a coil threaded by a magnetic conductor - independent of cross section of conductor?

I have a coil that surrounds (but does not touch) a small section of a ring of material with high permittivity. At the other end of the ring there is an attached magnet such that the ring forms a ...
0
votes
1answer
48 views

Magnets and magnetic Poles

If I take a cubical and spherical magnet where would its north and south pole be, which law governs this or is this simply a matter of probability? Also if I cut a bar magnet by its diagonal where ...
0
votes
2answers
84 views

Putting a capacitor into a strong magnetic field, will this change the capacity?

I'm wondering, does a magnetic field change the number of electrons, placed and displaced on the two plates of a capacitor. To prove or disprove this, I think the capacitor could be connected to an ...
0
votes
2answers
47 views

What causes the pattern you see when you hold a strong magnet near a CRT TV?

When you hold a powerful magnet near an old-style CRT TV, you see an interesting pattern, which "shows up the field lines" (see ...
0
votes
3answers
126 views

Why doesnt magnetic and electric field lines collide?

Why cant they meet or cut each other. I know magnetic field lines dont intersect with magnetic field lines and electric field lines dont intersect with electric field lines but why dont these ...
0
votes
5answers
96 views

How is the electromagnetic field made?

I know that an electric field is created by a particle with a charge and that a magnetic field is created by a moving charge but how do they combine to make a electromagnetic field?
3
votes
1answer
43 views

Magnetic field around a current carrying conductor

Would the magnetic field produced by a current carrying conductor be greater or smaller if the conductor is a bundle of small copper wires or a single, larger rod - assuming the same voltage? ...
36
votes
4answers
1k views

Is there an underlying physical reason why the Coriolis force is similar to the magnetic component of the Lorentz force?

I couldn't help but notice that the expression for the magnetic component of the Lorentz force, $$\mathbf F = q\,\mathbf v \times \mathbf B\,,$$ is very similar in its mathematical form to the ...
0
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0answers
15 views

Can a magnetic field affect the streaming current in high velocity water?

When you flow water at high velocity through a pipe you get a streaming current close to the pipe surface. If you were to then apply a large magnetic field across this pipe (perpendicular to the ...
1
vote
2answers
55 views

The Strength of the Tangential and Radial Components of a Dipole Magnetic Field

I am following along well several textbooks (Geophysics) that helps me understand the in-depth physics behind the magnetic field of a dipole magnet. I understand that the basic magnetic potential ...
0
votes
0answers
18 views

Can we magnetize magnetic tape / disk with constant magnetic field?

I am remember that have read in childhood, that tape recorders require alternating magnetic field to work. Is this true? Is there any difference between magnetizing by constant and alternating ...
0
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0answers
38 views

Inconsistencies in data: magnetic field in solenoid

In lab for our Calculus based Electricity and Magnetism course we are, for one portion of our lab, exploring the relationship between increasing the number of loops in a solenoid and the magnetic ...
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0answers
36 views

Adding magnetic dipoles and finding the field [closed]

If I have three magnetic dipoles and I want to model the field they produce together, how would I calculate that so I can model it in Mathematica? Assume the poles are permanent magnetic dipoles ...
-1
votes
1answer
81 views

Why Different charges attract while they should repel? [closed]

When I started studying magnetic fields, my teacher was always telling me that strong fields push the bodies to weaker fields, so i tried to apply the same concept to charges in the following picture: ...
0
votes
0answers
13 views

How to describe the effect of laminating the transformer core?

Is there any mathematical expression to describe how the power loss by eddy currents can be minimized by laminating the core of a transformer?
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1answer
36 views

Source of energy, work of magnetic field

Suppose I have a constant magnetic field, and I switch it off (abruptly or slowly) , a ring of uniform charge would acquire same angular velocity if it was present in a plane perpendicular to B and ...
1
vote
1answer
111 views

What is the nature of the magnetic fields? [closed]

In this question, I am hoping to find out if there is an explanation to the magnetic hidden forces. In other words, what causes these fields? Is there any suggested theory, or any confirmed ones ? ...
1
vote
1answer
62 views

Magnetic field current loop [duplicate]

Why does a loop of irregular shape carrying current located in a magnetic field change to a circular shape? Will this always happen assuming the wire to be flexible? Even when the force is inwards? ...
1
vote
1answer
36 views

Magnetic property of substances

There are only few substances like iron, nickel, cobalt with magnetic property. But in chemistry, when we take account of molecular orbital theory, we can find magnetic properties of every molecules. ...
1
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1answer
48 views

Induced EMF of this loop?

Consider a simple loop like so: And in-front of this loop are a series of wires that would cover the whole are of the loop, these wires are parallel to one another, and they have current flowing ...
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0answers
47 views

Current induced in concentric superconducting loops

Suppose you have two superconducting loops, concentric, in a plane. Also suppose that their radii, $R_1$ (outer) and $R_2$ (inner) have the same order of magnitude (so you can't assume $B$ through the ...
0
votes
1answer
61 views

Force on an electric dipole moving through a magnetic field

A dipole of moment $\vec{p}$ where p is fixed, moves with velocity $\vec{v}$ though a magnetic field $\vec{B}$. Show that the force on the dipole is ...
0
votes
1answer
52 views

Uniqueness of the magnetic vector potential?

I am trying to find the magnetic vector potential a distance of $s$ (cylindrical radial variable) from an infinite wire carrying current $I$. The magnetic field at a distance $s$ from a wire is ...
3
votes
0answers
36 views

Is it possible to do absolute magnetic field (flux) measurements using a SQUID?

In DC squid operation, the SQUID is usually flux-locked into a position on the flux-voltage curve, and the change in supercurrent required to maintain that lock point is used to determine changes in ...
4
votes
1answer
90 views

Why does a Heisenberg magnet break the O(3) symmetry in stead of SU(2)?

As stated in the question, why does a Heisenberg magnet break the $O(3)$ symmetry while degrees of freedom of the underlying spins are $SU(2)$?
0
votes
2answers
68 views

Why is the interaction energy of a dipole and a magnetic field *negative* when they are parallel?

The interaction energy between a magnetic moment, $\mu$, and an applied magnetic field, $B$, is given by $$\varepsilon=-\mu \cdot B$$ That negative sign is confusing my inuition. If we expand the ...
0
votes
1answer
39 views

A question gravitation and magnetism? [closed]

Suppose I have a magnet and I put a piece of iron next to it, then the magnet will attract it. Now if I put a piece of wood in front of the magnet and the piece of iron, the iron will not get ...
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votes
1answer
59 views
3
votes
1answer
73 views

Relation between Zeeman effect and Larmor precession

I'm wondering if there's some intrinsic reason that the precessional frequency, $\omega$, of a spin about an external magnetic field matches the frequency of a photon emitted (or absorbed) in ...
1
vote
1answer
28 views

Lorentz Force and Apparent Conservation of Momentum Violation Useful for Unidirectional Force?

My understanding is that the apparent violation of Newton's Third Law by the Lorentz Force necessitates a description of the system that describes the "missing" momentum as being absorbed/carried by ...
0
votes
4answers
83 views

Can light be warped by a magnetic field? [duplicate]

I was thinking and came up with the question "Can the path of a photon be warped by a strong magnetic field?" I tried searching online for an answer but couldn't find much scientific evidence of it ...
0
votes
2answers
30 views

What is filtered through the linear polarization of EM light? E field, B field or both?

I know that for EM waves (i.e sunlight) for any E wave in any direction, there is B field perpendicular to it. However, when we pass that EM wave through the linear polarization filter, what actually ...
2
votes
3answers
120 views

Why do charged particles follow magnetic field lines?

This may seem like a dumb question, but I can't think of the answer. The context I am curious about is the solar wind. Specifically particles flowing out of coronal holes and following the magnetic ...
2
votes
0answers
28 views

critical magnetic field superconductivity suppression in SQUIDs

Superconducting quantum interference devices are used as very sensitive magnetometers. However, on the wikipedia page, it claims that SQUIDS can be used to measure fields up to 7T. How can a device ...
0
votes
0answers
52 views

Magnetic field of a solenoid in a soleniod

I understand that using ampere's of an infinite soleniod is $$B = {\mu _o}nI$$. However, what if we have two infinite solenoids, where there's a solenoid of radius a and another of radius b. What ...
0
votes
1answer
101 views

Magnetic Potential Energy

Does a charged rod or a shell have a magnetic potential energy when it is kept in a uniform magnetic field? Also, can anyone quantitatively explain why a wire loop carrying current would tend to be ...
1
vote
1answer
73 views

Landau levels in 2D

I seem to be having a very basic misunderstanding of Landau levels in 2D. Consider the derivation give on page 7 here, where we consider electrons free to move in 2 dimensions, with a magnetic field ...
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0answers
22 views

2D electron gas in magnetic field

I am trying to understand the derivation for the wavefunctions and levels of free electrons 2D in a perpendicular magnetic field. The usual prescription is to take a vector potential ...