Magnetic dipole Definition and 115 Threads

I just wanted something to play with so I thought of this problem and solved it but now I have questions about it. Consider a charged particle with charge q and mass \mu which is constrained to move on the surface of a sphere of radius R. There is a magnetic dipole with moment \vec m=m \hat z...

Are there any experiments or theories about the relation between magnetic dipole moment orientation and velocity vector of free electrons?

Homework Statement The Earth's magnetic dipole moment is 8.0 x 1022 A m2. (a) What is the magnetic field strength on the surface of the Earth at the Earth's north magnetic pole? You can assume that the current loop is deep inside the earth. 6.17e-5 T (b)How does this compare to 5.0 x...

Does anyone know how to calculate the magnetic field or flux of a uniformly moving magnetic dipole with magnetic dipole moment \vec{M} pointing along the direction of motion? Thanks

Homework Statement 1. A wire of length L and carrying current I is bent into a square loop to form a magnetic dipole. This dipole is then oriented in a uniform magnetic field of magnitude B such that the dipole is in its lowest energy state. What is the value of the dipole's energy with this...

imagine a door shaped circuit in the between a south and north pole such that the long sides are perpendicular to the magnetic field created by the magnet , now in my physics book , it says that the torque that rotates the door is equal to B * Md where Md is the magnetic dipole moment which...

Homework Statement The relationship of dipole force and distance is noted by F ∝ ##d^{-3}##. One magnet is placed on a weighing scale and set the mass is set to equilibrium. Another magnet, with its positive end pointing down, is lowered from directly above towards the positive end of the...

How they know, how to see the spin of electron>?? Without external field applied, there is random dipole in the paramagnet. for diamagnet, without external field , there will be no dipole exist. Thanks.

I have read about Biot-Savarts law but I have no idea how to solve it when the curve is dependent of some variable. My books in mathematics don't help, nor my books in physics. You are welcome to give me a link where I can read about this, but first let me know if I have got it right this far...

How to calculate the magnetic dipole moment?? Does anyone out there know how I can calculate the magnetic dipole moment of a simple bar magnet? Or any kind of magnet? Without using this formula: \tau = μ x B

Homework Statement Homework Equations The Attempt at a Solution I found dB/dr to be constant near r = 0, so it's a straight line, implying B increases linearly with r near r = 0. For the second part, I assume the setup is as such, if not placing the dipole with its axis parallel to the coil...

I can do this derivation the old fashioned way, but am having trouble doing it with einstein summation notation. Since \vec{B}=\nabla \times \vec{a} \vec{B}=\mu_{0}/4\pi (\nabla \times (m \times r)r^{-3})) 4\pi \vec{B}/\mu_{0}=\epsilon_{ijk} \nabla_{j}(\epsilon_{klm} m_{l} r_{m} r^{-3})...

Homework Statement I'm not sure how they got the components of the B-field in the r and θ direction. I know the B-field along the ∅ direction is zero though. The Attempt at a Solution Here I have found the B-field at points P, Q and S that are very far along the z, x and y axis...

I am simulating protons and electrons in a simulator that runs 1 femto seconds per second up to 1 second per second. So it can accurately show the passage of charge particles through space with data being updated on their displacement, velocity and acceleration. However I am now adding in...

Hello, I have this problem. I calculated the dipole energy of a dipole moment in an external field using the equation U_m=\frac{1}{2}\int\vec{A}\vec{J}dr^3=\frac{1}{2} \vec{\mu}.\vec{B} however when the force on a dipole is calculated using \int\vec{J}\times\vec{B}dr^3 the formula...

Two permanent magnets are on the table some distance apart and having some arbitrary orientation relative to each other. When we let go of them they will rotate and translate until they stick together. I am looking for suitable equations to model this interaction on a computer. Also, if anyone...

Hi The energy U of a magnetic dipole in an external magnetic field is given by U = -\mu \cdot B so the energy is zero when they are perpendicular and maximal when they are antiparallel. This makes very good sense intuitively. Quantum-mechanically we have that \mu = -m_Fg_F \mu_B...

Homework Statement I am so stuck on this, and would be very thankful for any help! a). Calculate the magnetic dipole moment of a single atom, based on the following model: One electron travels at speed 7.40 × 10^6 m/s in a circular orbit of diameter 2 × 10^-10 m. b). The individual atomic...

Homework Statement I have two questions. Both involve derivations from textbooks, not end-of-the-chapter problems. The two textbooks are Quantum Mechanics by Griffiths, and A Modern Approach to Quantum Mechanics by John Townsend. My first question is about the discussion of Larmor...

[SIZE="1"]Sorry for my lack of knowledge, I'm in Grade 7 I just learned that Magnets have dipoles--like this: If those dipoles formed a circle, wouldn't it be possible to create perpetual motion?

1. when there is a current in a loop and it is placed in a magnetic field then there will be the torque on it along the direction of mxB axis.but that axis will pass through which point.will that torque act through the center of the loop only?? 2. suppose a current (I) carrying loop (of R)is...

Though this might be absurd, I would seriously like to know the average magnetic dipole of a magnet. For example, you might consider a regular magnet in a remote control car's motors, or any other suggestions too. And I have one more doubt- I know that e.m.f=-d(phi)/dt and phi=integral(B.dS)...

Hi. So, you surround a ferromagnet with a solenoid. Run current through solenoid to create B field withing. 2 Questions: 1:Why do the magnetic dipole moments in the ferromagnet "align" with the magnetic field of the solenoid? Doesn't lenz's law say that the magnetic field within the...

I have a Nickel cylinder, 5 micron in diameter and 10 micron in length. I know the external field \vec{B} is 80 gauss, what is the formula for the magnetic dipole moment of this cylinder in the field? Now I only have the formula for magnetic dipole of spheres, which is \mu = \frac{4}{3}\pi...

Hi, What direction does the electron's total magnetic dipole moment point relative to it's total angular momentum vector L+S? It seems to me that it would point oppositely to J=L+S since the spin magnetic dipole moment and the orbital magnetic dipole moment are both opposite to L and S, but...

Explain how an atom may have a permanent magnetic dipole moment? Many thanks...

This is part 2 of problem 4.8 from "Physics of Atoms and Molecules - Bransden, Joachain" Homework Statement Deduce [4.106] from [4.105] Homework Equations \tilde{M}_{ba} = - \frac{m\omega_{ba}}{\hbar c} \langle \psi _b \vert z \dot{x} \vert \psi _a \rangle [4.105]...

I am trying to figure out how the TEM wave looks like and how it propagate outward. Attached is a pdf of a drawing with only the solenoid and show the winding that the current is flowing in CCW and a reference. Also I draw a loop with one resistor and show the induced current and the polarity of...

Hello, I have doubts with this problem, I'm not sure, if my solutión is right, so, here we go Let's two equal charges with the same charge but opposite signs, positive and negative, in a circle, such a distance between them is constant and equal to diametre of the circle. Both charges, turn...

Do Gluon's have a magnetic dipole moment ? I hope this is the right place to post this.

simple magnetic dipole moment with impossible field lines? clueless. Hello, I'm taking a first year university course in electromagnetism. At a certain point we came upon the torque on a current loop in a uniform magnetic field. There we introduced the magnetic dipole moment \overline{\mu} =...

As in Feynman's lecture on physics vol 2, he showed that the "true energy" of a magnetic dipole(current loop) in an external B field is m*B, not -m*B. Basically the argument is if you want to pull a current loop from infinity to the final position, you must do extra work to keep the current in...

Homework Statement A circular coil having 20 turns and a radius of R = 12.8 cm carries a current of 2.70 A. It is placed in a uniform magnetic field of 60.0 mT. The initial angle between the magnetic moment of the coil μ and the magnetic field B is 26.0o. 1)Calculate the magnetic dipole...

Homework Statement ..Is it possible to find the Magnetic Dipole Moment of a point particle with spin quantum number 2 and mass equal to that of a proton. I'm not sure how to start this question as there's nothing on it in the textbooks I have! Thanks

Find the first integrals of motion for a particle of mass m and charge q in a magnetic field given by the vector potential (scalar potential \Phi= 0) (i) of a constant magnetic dipole m_{d} A=\frac{\mu_{0}}{4 pi}\frac{m_{d} \times r}{r^{3}} Hint: Cylindrical coordinates are useful...

i want to learn about magnetic dipole moments but don't have a good grasp on it

Hi guys, I'm involved in a research project regarding discrete bit patterned media and I was tasked to figure out how a magnetic force microscope works for imaging magnetic islands on thin magnetic films coated on silicon substrate, as part of a preparatory literature review. So I pulled out...

So I got a question on a E&M Midterm: There is a line current of I at the origin going in the Z direction. There is a magnetic dipole of: \vec{m}=m_r\hat{r}+m_\varphi\hat{\varphi} located at (r,\varphi). What is the force and torque on this magnetic dipole? So I used the equations...

Homework Statement You have a coil of N turns, with current I through it. It is in a magnetic field B, which causes it to feel a torque. Give an expression for its magnetic dipole moment. Homework Equations The Attempt at a Solution Well, I know magnetic dipole moment is A...

I am not understanding why the potential energy (U) for a magnetic dipole is at it's maximum when the magnetic dipole moment is antiparallel to the magnetic field (B), why U is at it's minimum when the magnetic dipole moment and B are parallel, and why U is zero when B and the magnetic dipole...

Let's say that an electron is moving with constant velocity through a magnetic field. If the magnitude of the field is the same everywhere in space and if it is perpendicular to the velocity of the particle everywhere, the electron will follow a circular path. We all know that. What I need to...

What is the nature of magnetic dipole radiation? Does a rotating bar magnet give rise to electromagnetic radiation(magnetic dipole radiation to be more specific)??

I'm seeking some clarification on a topic found in Jackson 'Classical Electrodynamics' Chapter 5. This deals with the magnetic field of a localised current distribution, where the magnetic vector potential is given by \vec{A}(\vec{x}) = \frac{\mu_0}{4\pi}...

How can the magnetic dipole of a molecule (Oxygen for example) affect radiation absorption?

I've run across a diagram that really is driving me crazy. The torque on a mag. dipole should be simply be τ = m X B, where B is the external field as usual. In the image I've attached, there is a large external field, not shown, in the direction of Z which is holding the dipole in the +Z...

Guys, I don't quite understand the concept of magnetic dipole moment as a vector. Suppose we have a magnet (like a rod) in 3 dimensional space. North pole at (0, 0, 0) and South pole at (0, 1, 0). How would the magnetic dipole vector \vec{m} be oriented? Thanks.

[SOLVED] Griffiths 5.58 Homework Statement A uniformly charged solid sphere of radius R carries a total charge Q, and is set spinning with angular velocity \omega. What is the magnetic dipole moment of the sphere.Homework Equations The Attempt at a Solution The magnetic dipole moment of a...

Homework Statement Show that the magnetic dipole moment M of an electron orbiting a proton nucleus of a hydrogen atom is related to the orbital angular momentum M=(e/2m)L Homework Equations M=NIA, Torque =MB, F=qvB=v^2/r, L=Iw=mrv=rp (where p=mv) N=1 in this case I assume? The...

There has been some dispute in the past about the validity of the electric current model of a magnetic dipole producing a force \nabla (\vec{m}\cdot\vec{B}) versus the magnetic pole model producing (\vec{m}\cdot \nabla)\vec{B} (see e.g. Boyer `87). I think for elementary particles this dispute...

Homework Statement A uniformly charged solid sphere of radius R carries a total charge Q, and is set spinning with angular velocity \omega about the z axis. (a) What is the magnetic dipole moment of the sphere? Homework Equations \vec{m} = I \int d\vec{a} The Attempt at a...