Magnetic Definition and 1000 Threads

Suppose that we have an insulating cylinder with ##\rho_q##. If i move the cylinder towards ##+\hat{n}##, will it produce a magnetic field? My assumption is that since we have an insulator, then the electrons are bound and there cannot be a current, thus a magnetic field is not produced. Also...

https://blog.nationalgeographic.org/2014/01/03/dogs-sense-Earth's-magnetic-field/"...the first study showing a mammal not only being able to sense it, but also to exhibit a specific behavior in response to natural magnetic field variations. " In my view, dogs are nearer human consciousness than...

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So far as I know there are no monopoles in the electro-weak sector of standard model. So people look for it in the GUT and SUSY sectors. However, they are predicted to be heavy(order of Planck mass). There have been studies from LHC attempting to detect monopoles. So here are my questions: 1...

I am trying to understand but without a succes why symmetric magnetic field around ##Z## axis make that ##\hat \phi## magnetic field is zero I can't understand why it physically happens and also how can I derive it mathematically? What does the word symmetric means when talking about magnetic...

There's a constant magnetic field B. If a particle is acted on by a force qv*B (* cross) only, and the initial velocity v0 is normal to B, is the motion certainly a circular one (for any m, q, v0)? mv''=qv*B If one solves this equation (vector), it doesn't seem obvious.

Here, the correct options are A,D. Solution: I got A as answer as ∫ B.dl=µI. But, the answer to the question says that it is a solenoid and therefore Bx=0 for point P. Here I'm a bit confused. I know this system resembles a solenoid in some ways, then By must have some finite value, but...

I am sure I need to use Amper's law to do that. if I use the equation I mentioned above it easy to calculate the right side of the equation but I have problem how to calculate the path integral. I know from right hand rule that the magnetic field will point at $$Z$$ and the current is in...

I have an ordinary switchable magnet for holding tools to a lathe. It's like a magnetic force gearbox, but I can't quite understand the force multiplication. When placed on a steel surface the switch force is approximately ~5N on both finger and thumb at 1.5cm radius acting over a 3cm arc...

Ampere´'s law with the correction term I have a infinite cylinder with radius R with a current density , and magnetic field . I have to proof that it is acceptable to discard the correction term of term of ampere's law, while calculating the magnetic field, as long as it obeys the following...

Consider the static field configuration shown in the image. There are three layers: 0 = vacuum, 1 = magneto-optic fluid and 2 = covering shell. Each of these layers have their own permittivity and permeability (ε_i,μ_i) (isotrope). A uniform electric field H_0 = H_0/sqrt(2) * (e_x + e_y) is...

Consider a coil perpendicular to the ground falling with gravity. Under it, there is a magnetic field also perpendicular to the coil. When the coil starts penetrating the magnetic field there will be an induced current and therefore a magnetic force upwards. This magnetic force will reduce...

So I know that a compass points to the south magnetic pole, that is near the north geographic pole. Let's consider the Earth to be a magnetized bar with all 4 poles aligned (for didactic purposes). The compass will try to "follow" the south magnetic pole, so, if I am in the Equator for example...

About this figure, the current in the opposite wires are parallel (and not anti-parallel). So, for instance for the first option the torque is zero; but I wanted to know what is the magnetic moment of this loop. Since I rely only on formula I've have no idea how to compute for this one.

The equation of motion can be integrated w.r.t. ##t## since ##\frac{d}{dt} (\mathbf{r} \times \mathbf{B}) = \dot{\mathbf{r}} \times \mathbf{B} + \mathbf{0}## $$\int (q\dot{\mathbf{r}} \times \mathbf{B} + m\mathbf{g}) dt = \int m\ddot{\mathbf{r}}(t) dt$$ $$\frac{q}{m} \mathbf{r} \times \mathbf{B}...

In this image of Introduction to Electrodynamics by Griffiths . we have calculated the vector potential as ##\mathbf A = \frac{\mu_0 ~n~I}{2}s \hat{\phi}##. I tried taking its curl but didn't get ##\mathbf B = \mu_0~n~I \hat{z}##. In this thread, I have calculated it like this ...

Thought of doing this one years ago! Basically, I want to 'see' the magnetic force lines that surround a conductor when energized (with an alternating current). I appreciate that what I will see (or at least I am hoping to see) is the pattern formed by the iron dust in response the the field...

Hello, in this problem I'm supposed to calculate de magnetic field due to a bent wire at any point of the x-axis after the bending of the wires. It is obvious that the part of the wire that is parallel to the x-axis makes no contribution to the field so we can focus on the other part of the...

Once I know the Hamiltonian, I know to take the determinant ##\left| \vec H-\lambda \vec I \right| = 0 ## and solve for ##\lambda## which are the eigenvalues/eigenenergies. My problem is, I'm unsure how to formulate the Hamiltonian. Is my potential ##U(r)## my scalar field ##\phi##? I've seen...

Magnetic fields are sometimes measured by balancing magnetic forces against known mechanical forces. Your task is to measure the strength of a horizontal magnetic field using a 12-cm-long rigid metal rod that hangs from two nonmagnetic springs, one at each end, with spring constants 1.3 N/m ...

If I put a very long steel plate above a coil with DC, the magnetic field above the plate will decrease because of the shielding of the steel plate. However, from the perspective of magnetci domain, some domains will be magnetized to turn to the direction of the magnetic field from the coil...

Hi, I have to check some questions answers for my homework (Problem 3.5 and 3.6). Please help me find this book solution manual.

So I'm mainly having trouble with part b as I have successfully completed part a. In part b I get an answer of 6.3 x 10 ^8 Amperes which my homework tool flags as incorrect. I'm clueless as to where to go from there or why my approach is wrong?

Hello, I'm searching for how magnetic field affects the thermal conductivity of the metal (such as steel in solid form). If someone suggests any article about it will be very helpful.

If the magnetic field is constant then no change in flux will bring no induced emf nor any induced current. With the loop is in rest position the external magnetic field will exert a force but to calculate that force with the help of magnetic field isn't obvious. If this were a charged loop, the...

The calculations for the magnetic field produced by a uniformly rotating charged sphere can be found in basically every book on electrodynamics. I wonder what happen with the magnetic fields produced by rotating rigid solid that also present precession and nutation movements. The question comes...

Hello, If you have an appropriately oriented conductive ring in a constantly changing magnetic field, current will flow in the ring. There will also be a magnetic field associated with the current in the ring. I understand (maybe ... ) that the current is due to the electric field which is...

How do we verify whether a condition on the magnetic vector potential A constitutes a possible gauge choice ? Specifically, could a relation in the form A x F(r,t) be a gauge , where F is an arbitrary vector field?

Hello, When a charged particle is inside a magnetic bottle at the right speed, the particle bounces back and forth and is confined inside the magnetic field. The magnetic force does not work on the particle hence the particle's kinetic energy remains constant. That means that the particle may...

1. Is it possible to perform the following, modified double-slit experiment with single electrons/electron beam: The slits are separated in such a way, that each leads to a separate magnetic trap. The traps have oppositely directed magnetic fields, so that the electrons entering them move in...

Unsure about this, but here is my attempt: B from the first wire: ##\dfrac {\mu _{0}I}{2\pi r} ## B from the second wire: ##\dfrac {\mu _{0}I}{2\pi r} ## Let the point be (x,y) Can I state that: ##\dfrac {\mu _{0}I}{2\pi y}+\dfrac {\mu _{i}\left( I/3\right) }{2\pi x}=0## Hence the magnetic...

So this was a section taken out from a question which I am trying to do shown below I have drawn a sketch to help me visualise of what is going on I have used Fleming's left hand rule to help me determine what direction the force is facing on each side of the coil. For the last part in...

a) 248*10^3 eV for 248kV Calculate the energy in J K=248*10^3*1.6*10^-19 =396.8*10^-19 J b) K=(1/2)mv^2 v=sqrt(2k/m) =sqrt((2*396.8*10^-19)/1.67*10^-27) =218^10^3 m/s c) r=mv/qB =1.67*10^-27*218*10^3/1.6*10^-19*1.5*10^-4 =15.17 mr=mv/qB...

We have a retarded magnetic vector potential ##\mathbf{A}(\mathbf{r},t) = \dfrac{\mu_0}{4\pi} \int \dfrac{\mathbf{J}(\mathbf{r}',t_r)}{|\mathbf{r}-\mathbf{r}'|} \mathrm{d}^3 \mathbf{r}'## And its curl, ##\mathbf{B}(\mathbf{r}, t) = \frac{\mu_0}{4 \pi} \int \left[\frac{\mathbf{J}(\mathbf{r}'...

Here i tried this way (see picture) Please tell me am i right or wrong. Also they says find the change in magnetic field with time using Faraday's law in a rectangular loop. How can i solve that??

It seems I don't understand how magnetic shielding supposed to work. I tried shielding a wire, using some ferrites, but it doesn't work. I assumed the magnetic field will concentrate in the magnetic material, bypassing the meter magnetic loop, so less will be measured by the meter. I thought the...

As I understand it, it is the magnetic part of electromagnetic radiation which creates a current (AC) in a radio receiver (i.e in an antenna) which can be translated into sound/graphics and so on. Is this correct? I mean in the sense that it is the magnetic field in the incoming radiation which...

I had started off by equating the magnetic force to the centripetal force, to find the mass of a single ion. Then calculated the mass of what 1 mole of that ion would weigh to identify what the ion is Hence the answer would be nitrogen (option C) as 1 mole of nitrogen weighs 14g Would this...

Hi, I'm trying to find the magnetic field B using F = qV * B. I have F = (3i + j + 2k) N V = (-i +3j) * 10^6 m/s q = -2 *10^6 C Bx = 0 I don't know how to resolve a 3 dimensional vector equation. B = F/qV makes not sense for me.

My attempt: I realized after i had tried to solve the problem that the current must be constant in the cables. But no information about where the cables has radius a and b is given so how would I go about to find an expression for the current? Thanks in advance!

Hello all: Reading about HB-11 start up and they mentioned laser induced magnetic field : How is that created and the size of the magnetic field is in kilo Tesla range anyone heard of that Best Hagop

Why do the magnetic fields in-between the wires does not seem to cancel? Even those outside each wire? (the fields do are not in opposite direction). Yet most of the people I have talked to until now says that such magnetic fields do cancel? I am confused...

Hello, sorry for this stupid question but I am getting confused with equations and I need some help. My problem is the following: I have a dipole with known magnetic field (B=0.234T), it is 110.6 mm long and 89 mm wide (mechanical dimensions). I want to calculate deflection of particles...

I know that there is a known equation to calculate the magnetic field strength of a rotating disc which I have made use of in here Do you agree that revs per minute of the disc turns out to be 9337 rpm? Thanks for any help! Much appreciated

Hey everyone So this is question shown below I'm not so sure where to begin with this, but I thought I'd work out the net magnetic field first How would I work out the magnetic field strength that is acting on the vertical current-carrying wire. Since I do not know what d is in this case...

Hi, Here is a multiple choice question I am stuck with and would appreciate some guidance: The mark scheme for this paper says it is option A - 0N. I didn't get that at all. If a current carrying wire is in a magnetic field with some component perpendicular to the field then how can it be...

How and why does a changing magnetic flux induce an emf? Why doesn't a static one also produce one? How are the electric and magnetic forces related? Why do you move a wire through a magnetic field so that the wire, the motion, and the magnetic field are all mutually orthogonal in order to...

I'm trying to understand the relationship between the "number" of field lines passing through a region and the magnetic force in this region.I understand that the drawings are of course conceptual: we cannot draw "all" the field lines (although can be visualized with iron fillings).Also the...

Since the magnetic field is pointing down, I can derive that the magnetic force is into the page. With this, I can't really imagine how the particle can move in a circular motion as I cannot visualise how the centripetal force will look like when the force is into the page (instead of usual...

I can create a fairly strong magnetic field by leading current through a copper coil. However, I cannot then with that magnetic field create a current (not a useful one at least) in an object made out of copper. I understand that this is because copper lacks of magnetic properties. For instance...