Magnetic Definition and 1000 Threads

I am trying to derive the equation ##\vec{\Gamma} = \vec{m} \times \vec{B}##, where ##\vec{m} = I \vec{A}## is the magnetic moment, and ##\vec{A}## is normal to surface ##A##, from the Lorentz force law ##\mathrm{d}\vec{F} = I \vec{dl} \times \vec{B}##. For an arbitrary closed current loop ##C##...

What happens when magnetic field cancel. Where do they go. Do they just vanish or return to the vacuum? In a GFCI receptacle we have in most of our homes. The sense coil can output zero when there is deviation from net magnetic field between the line and neutral. This means the cancellation...

Homework Statement A square coil (sorry, its not "current carrying" as shown in diagram, my mistake) of length L is released from rest, in a horizontal uniform magnetic field going into the plane of paper, of length 2L. What can you say about the coil's acceleration? Homework EquationsThe...

I'm not sufficiently educated on this stuff to properly describe the question. Sorry. Consider the following. a primitive gauge is set up in order to observe the differential air flow between two sources. Assuming static pressure linearly corresponds to differences in flow. so balancing air...

Homework Statement 3. A spherical conducting shell is placed in a time-varying magnetic field. Is there an induced current along the equator? Homework EquationsThe Attempt at a Solution I don't know what is the right answer. I mean...why not? Is the magnetic field is changing, there should be...

Homework Statement A DC current is flowing between two electrodes through a iron disk medium. Positive is attached to the copper shaft of the disc and the negative is attached to the outer brass periphery of the disk. The radius of the disk is 2,54mm (1 inch) and the height of the disk is 1cm...

So I was trying to see what the result for the spin precession would be if the magnetic field pointed in the y-direction instead of z. I feel like either something with what I'm doing is wrong or, I'm just overlooking something because I keep getting complex energy eigenvalues. So what I'm doing...

Homework Statement A wire carrying a current I in the positive x direction is located along the x axis. The wire is of finite length and is located between x = -L and x = L. Find the magnetic field at a field point located a distance a away from the wire. Homework Equations Biot-Savart law...

Hello, could someone help answer this question for me: How would the path of a conducting sphere (i.e. AL) be affected as it passes through a strong uniform magnetic field orthogonal to the direction of motion. I believe the Lenz effect/Eddy currents will create a magnetic field opposing the...

Homework Statement A current of 50A flows through a copper wire of diameter 0.5 * 10-2m. The magnetic induction on its surface will be: A)4*102T B)4*10-2 C) 4*10-3 D)none of these Homework EquationsThe Attempt at a Solution I just want to verify my solution, as the answer keys are currently...

Hello, I have found an interesting alternative to the common loudspeaker motor in the form of a magnetic repulsion circuit. The picture below shows the basic idea. A coil is suspended between two magnets (or pairs of magnets) that are a certain distance apart. The magnets are mounted so that...

I know, geologicaly speaking, that "suddenly" is a relative term. So when they say that Earths magnetic field suddenly switches, how long are we talking about. Days, hours, centuries?

When a nucleus is placed inside an external magnetic field, it aligns itself parallel to the field, as that is the most stable position for it to be in. In more technical terms: it acquires an alpha spin. When you shine radio waves at this nucleus, it absorbs energy and flips over anti-parallel...

Homework Statement Hello all, not really sure what to title this. Heres the question: Ceicil sets a trap. According to ceicil, all she has to do is somehow attach a conductive bar with resistance 1Ω to the turkey and then get it to walk along a wire loop in a region of 100T magnetic field (as...

Does electrons or other particles attracted towards a magnet due its magnetic momentum?

Homework Statement Homework Equations energy=-u_0(B)[/B] The Attempt at a Solution According to the back of the book, a. energy level separation increaess b. mean energy decreases which makes sense since B is increasing then E must be increasing negatively. c. negative (not too sure why...

Homework Statement A metal strip 6.5cm long, 0.88cm wide, and 0.76cm thick moves with constant velocity, magnitude v along positive y-axis, through a magnetic field, B=1.2mT along positive z-axis. A potential difference of 3.9x10^-6V is measured between points x1 and x2 (as shown in...

Hello! I am reading Schwarz's book on QFT and in chapter 17 he introduces the anomalous magnetic moment. I am not sure I understand a step in the derivation (from a mathematical point of view), when going from 17.23 to 17.24 (I attached a SS of it). I was able to get certain terms, but I am not...

Greg Bernhardt submitted a new blog post Are Magnetic Field Lines Real? Continue reading the Original Blog Post.

The Earth's magnetic field is cylindrically symmetric and can be described using cylindrical coordinates, (ρ,z,φ). The components of the magnetic field are given by: (B_φ) = 0 (B_ρ) = −∂A/∂z, (B_z) =(1/ρ) * ∂(ρA)/∂ρ. The vector potential for a dipole field is given by (A_φ) = (B_e)(ρ) *...

I know that total magnetic moment of an electron (I am not sure if it is magnetic moment of electron or atom, please clarify this) is sum of magnetic moment caused by orbital motion and spin angular momentum. So, Total magnetic moment = Orbital magnetic moment + spin magnetic moment Do I have...

Hi, I'm trying to find a database in which I could enter a chemical formula and then locate a table of physical properties of that compound (or references). For example, whether the material exhibits magnetism, superconductivity, it's crystal structure, curie temperatures, conductivity, or...

Couldn't see this news posted elsewhere. Sound too good to be true?... Quote: "We have created a device that behaves like a diode for magnetic fields." https://phys.org/news/2018-11-defy-19th-century-law-physics.html I haven't read their paper yet.

Dear all. I would like to know the general expression of the ratio of the electric field strength E to the magnetic flux density B. I know E/B = c, where c is the speed of light, for a vacuum, but I want to know if this is stil valid for any material where the electric and magnetic fields are...

Homework Statement Find the magnetic field at point P. (P is at the centre of two infinitely long wires, carrying current in opposite direction. Homework EquationsThe Attempt at a Solution My guess is that since the current direction is opposite and distance between the point and the wires is...

Hi, I have a question about the rotation of a single-domain magnetic nanoparticle that is suspended in a ferrofluid immersed in an external field. Specifically, I am trying to work out the path that a normal vector on the surface of the sphere traces out in time. There are 2 ways the...

Just for the record, The text is Introduction to Electrodynamics (4th Edition) by David J. Griffiths Chap.6. What does "when the magnetic dipoles are aligned" mean? Does it mean Both moments are parallel to each other's magnetic field? i.e. ##m\times B = 0## for both? Or is it ##m_1\parallel...

Homework Statement In the figures below, a copper wire of circular cross section, A, has been bent into a square loop of side length, c, and arc welded at the seam for electrical continuity. Assume that the resulting square loop has a resistance, R, and a mass, M. The loop is originally held...

Homework Statement A deuteron nucleus (consisting of one proton and one neutron) has a mass of 3.34x10-27kg and a charge of 1.602x10-19C. The deuteron nucleus travels in a circular path of radius, 6.6mm, in a magnetic field with magnitude of 2.1T. A) Find the speed of the deuteron nucleus B)...

Suppose a straight current carrying wire is immersed in a uniform electric field along its axis. For this problem, please don't worry about complete loops or return paths, just consider a segment of straight wire carrying a current. Since external electric fields don't get inside conductors due...

Dear helpers, I working on an projekt for the University and for that I have to calculate forces between different magnets. The question that I have is: "Is there a way to calculate the force between two magnets if one is completely known and the other unkown. But you know the B-field of the...

Today I came across an article (not from a authoritative journal) about "Quantum Navigation". https://www.wired.com/story/quantum-physicists-found-a-new-safer-way-to-navigate/ It is about a method to do navigation by detecting anomalies in Earth's magnetic field. I tried (and failed) to find a...

Homework Statement A) Three infinite, current-carrying wires are arranged as shown below. In terms of the given quantities, determine the magnitude and direction of the magnetic force per length acting upon wire 2. (Part A.jpg attached) B) Three infinite, current-carrying wires are arranged as...

I have a thin copper tube of 4.4mm inner diameter (inside a long ionizer plasma cannon) and I want to fill in with hydrogen plasma fully ionized at low temperature (100eV), what is recommended magnetic field to have the ions there without touching tha walls? The plasma life is about 0.5 seconds

Could I have hundred times the ground state or there is a limit? Is there a limit for excited magnetic momentum that if reached the nucleous explode or generate gammas? I suppose If I excite it it would spin faster but proportional to quantum values. Note: there is a "theory" to avoid electron...

Homework Statement The figure below shows a small circular loop of wire in the plane of a long, straight wire that carries a steady current I upward. If the loop is moved from distance x_2 to distance x_1 from the straight wire, what will be the direction of the induced current in the loop and...

Homework Statement A rod with mass of m runs on rails in a magnetic field. The rails are connected with a wire at x = 0 so that the rod and the rails together with this wire form a closed circuit. The distance between the rails is L, and the resistance in the rod is R. We assume that the...

I am trying to find a way to decrease the force between two magnets by putting a physical barrier in the middle of them. I’ve reasearched and found that Mu metals redirect the flux of the magnetic fields so those two magnets shouldn’t have any noticeable attraction between them. Of course...

Can someone help me to understand some of these steps? Why can we write ##\frac{1}{R} = \frac{sin(\phi)}{R}## and ##y = - cot(g\phi)##?

Are both magnetic fields emanated from an electromagnet fed with a current spike from a charge capacitor and a rotating static magnetic field from permanent magnets instances of time varying fields? The permanent magnet would be attached to perhaps some rotating disc thus passing over a target...

I do not understand the theory of moment of nuclei I read here: http://www.sjsu.edu/faculty/watkins/nuclearmoment3.htm that the magnetic moment of Hydrogen is 2.79284734 magnetons = 2.79284734*9.274009994e-24 joules/tesla =2.59e-23 joules/tesla So if I make to rotate a proton using 150 keV...

Homework Statement See picture Homework Equations Dont think so. The Attempt at a Solution I get D, the answer is D. I think it is D because only half a magnetic wave would appear on the inside of the wires as it is a sine wave. If you have more information on answering the question, please...

Can anyone help with this please... Would the following work? Magnetic inertial Confinement Hybrid Fusion Reactor. Peeta Watt lasers are focused on the plasma in the equatorial plane of the multi mega amp plasma pulse within its’ torous geometry between the center post and the merging...

I used the following links: C++ software using elliptics integral at: https://tiggerntatie.github.io/emagnet/offaxis/elliptic_c.htm And the calculator here: https://tiggerntatie.github.io/emagnet/offaxis/iloopcalculator.htm I placed some values and obtained Br smaller than Bx, so I do not know...

Homework Statement What causes electric field? What causes magnetic field? (I) stationary electric fields (II) moving electric charges (III) a changing magnetic field IV) a current-carrying wire Homework Equations E=F/q B=μI/2πr E electric field F elecric force Q charge B magnetic field I...

Homework Statement An electron moving in the -z direction enters a region that has a uniform magnetic field in the +y direction. When the electron enters this region, what direction will it be deflected in? Homework Equations F=qv X B The Attempt at a Solution I tried answering this question...

Hi all. I am alluding to the Moving Charge in a Magnetic field problem by quoting an MIT lecture below. Scott Huges – Lecture http://web.mit.edu/sahughes/www/8.022/lec10.pdf Suppose we now examine this situation from the point of view of the charge (the “charge frame”). From the charge’s point...

Hi Please help me in understanding the kind the magnetic field used in an AC generator. Most of the figures (one shown in attached file) are shown with concave poles. Hence the field has to be radial. In such a field the angle between plane of coil and the magnetic field remains zero all the...

Hi all. I was wondering if time is dilated whilst traveling in a stable magnetic field that is generated by the object travelling, and if so, does this vary if you reduce or intensify the magnetic field? Also, what happens if the object is generating two opposing magnetic fields, would...

Homework Statement The question askes about the path of the electron. I need to know if I am doing it correctly whether it was asked for a proton or an electron. Homework Equations F=QV⊥Bsinθ The Attempt at a Solution I answered it C. Because it is an electron, I used my left hand. My thumb...