Dipole moment Definition and 205 Threads

I know the definition of the electric dipole moment is given by \mu = -e x, where e is the charge of electron and x is the displacement. I am thinking a mechanics counterpart of the dipole moment. We note that in mechanics, the moment is defined as the force cross the position vector. Consider...

Homework Statement A certain electric dipole is placed in a uniform electric field E of magnitude 20 N/C. Figure 22-59 gives the potential energy U of the dipole versus the angle θ between E and the dipole moment P. What is the magnitude of P? Homework Equations U=p(dot)E The...

Homework Statement A dipole of moment 0.50 e · nm is placed in a uniform electric field with a magnitude of 8.0 104 N/C. What is the magnitude of the torque on the dipole for each of the following situations? (a) the dipole is aligned with the electric field 0. N · m (this is correct)...

Dipole Moment! Ok I'm very tired because I've spent the past 50 minutes trying to figure out a problem that should take only 5. Someone please just take 2 minutes of your time to save me 20 more minutes. THis is a simple problem yet I cannot do it on my own, without my textbook and with what...

Homework Statement Show that the electric field of a "pure" dipole can be written in the coordinate-free form E_{dip}(r)=\frac{1}{4\pi\epsilon_0}\frac{1}{r^3}[3(\vec p\cdot \hat r)\hat r-\vec p]. Homework Equations Starting from E_{dip}(r)=\frac{p}{4\pi\epsilon_0r^3}(2\cos \hat r+\sin\theta...

Hi I want to calculate the electric dipole moment of point charges along the z-axis with distances a and with the charge distribution \varrho (\vec{x}) = q \delta (\vec{x}) - 2q \delta (\vec{x} - \vec{a}) + q \delta (\vec{x} - 2 \vec{a}) and of course \vec{a} = a \vec{e}_{z} I...

Homework Statement Can anyone explain why the direction of the dipole moment of an electric dipole is always taken as "from -q to +q" but not "from +q to -q"? In fact when we draw the electric lines of force we are only drawing in such a way that they start from +q and terminate at -q.Then...

Homework Statement I'm trying to find the dipole moment of The surface charge distribution is: \sigma = \sigma_{0} sin 2 \theta Homework Equations The Attempt at a Solution p_z=\int_{0}^{\pi}{\sigma* z* dA } = \int_{0}^{\pi}{(\sigma_0 \sin{2...

Calculate the dipole moment of a spherical shell of radius 'a' whose surface charge density is σ=σ0(1+cos(θ)). The origin is at the center of the sphere. What I know: 1) p=∫r'*ρ*dV' I'm having trouble understanding how to transform this equation so that I can calculate the dipole moment...

I understand a little about dipole moment. Its like a compass which aligns itself when an external field is applied. But a little fuzzy when it comes to dipole moment of water. why is it 105 degrees. How does this come into play when they are impinged with microwaves or time varying E field.

hi I am student of graduate and want to clear the picture of MAGNETIC MOMENT of electron in my mind.can someone tell me that if an electron is moving in its orbit constituting its intrinsic spin(1/2) ho can it forms dipole moment(to poles) when place in magnetic field?and what is the difference...

a water monomer has HOH angle of 104.5 and OH length of 0.98 , partial charges are +0.4 on H and -0.8 on O. The reported electric dipole moment for this monomer is 1.86D. I tried to calculate it and got 2.3 D. The way I do it is by multiplying the distance between the center of the H-H and the...

Can someone give me a clear picture of it's physical meaning? What does a molecule having dipole moment signify? All the explanations I've seen are very hazy.

In two-level system, with external field applied, why there is no permant dipole moment? In classical point of view, dipole moment is coming from displacement of positive and negative charge. In quantum case, inside the atom, even no external field, there is certain probability for the electron...

Help me to sort out this problem:: Prove that, "integration over[J(r)dr]=del(p)/del(t)" ... where p is the electric dipole moment ... please as soon as possible, reply me ...

Hi , How to calculate the diploe vector of benzene ring?. what is the formula for calculating the diploe moment?. Thanks in advance Aneesh

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...

1. In an electric dipole moment, assume that both charges are positive and find the electric field "E" at point "P", assuming X>>d, where "d" is the distance between the two charges and "X" is the distance of point "P" from the center of the dipole. I have thought a lot about it but I am very...

how to calculate the dipole moment of a molecule?? using electronegative values of periodic table ??

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...

Homework Statement I we know the eigenstates of the system be |\psi_1\rangle and |\psi_2\rangle. Current state of the system is |\Psi\rangle = c_1 |\psi_1\rangle + c_2 |\psi_2\rangle Try to find the expectation value of electric dipole moment \mu (assume it is real) and write it in...

Homework Statement What is the dipole moment for the following charge arrangement? (Please view attachment) http://img378.imageshack.us/my.php?image=dipoleal6.jpg" http://img378.imageshack.us/my.php?image=dipoleal6.jpg Homework Equations p = \int r' \rho (r) d \tau '...

Homework Statement what is the potential 18 cm from a dipole moment 2.6nCm at a) 42 deg to axis b) on the perpendicular bisector note: dipole separation << 18cm Homework Equations electric dipole moment, p = qd where q is charge, d is distance electric potential for point...

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}...

Hi, Is dipole operator symmetric or antisimmetric? Or, in other words, do the transition dipole moments from state 1 to the state 2, and from the state 2 to the state 1 have different sign? I.e. mu_12 = - mu_21. As far as I understand, the diagonal elements for the dipole operator...

Homework Statement Consider two dipoles with moments u1 and u2 arranged as in the following diagram. Each dipole is depicted as two charges of equal magnitude separated by a distance d. The centre-to-centre separation of the two dipoles is the distance r. The line joining the two dipole...

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...

[SOLVED] Griffiths dipole moment Homework Statement On page 244 of Griffiths E and M book, Griffiths defines the magnetic dipole moment as \vec{m} = I \int d\vec{a} . Then in problem 5.58, he asks us to calculate the dipole moment of a uniformly charged spinning solid sphere. How is that...

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...

I am having some trouble starting this one. http://img301.imageshack.us/img301/8080/79432817ke4.jpg Im not sure if I am supposed to replace the psi(v) with some ground state harmonic oscialltor function or not. If so, do I then just take the integrals and then divide 1 to 2 by 0 to 1 to...

A needle suspended from a string hangs horizontally. The electric field at the needle’s location is horizontal with a magnitude 3.7*103 N/C and is at an angle of 30° with the needle. There is no net electrical force acting on the needle, but the string exerts a torque of 3.7*10-3 to hold the...

There is a dipole moment that is symmetric along a y-axis and is along an x-axis. A charge -q is placed a distance a along the -x direction and a charge +q is placed a distance a along the +x direction, making the distance between the 2 charges 2a. I'm supposed to show that the electric field...

[SOLVED] Finding the Magnitude of a Dipole Moment Hi there, I'm new to posting, but I've used this forum many times to help me with my homework :) I went the "take a photo of the textbook" route (there is a picture with the problem), so I hope that's acceptable. Homework Statement A...

Hi I was wondering if anyone could give me info about atomic electric dipole moment at a very fundamental level (fenomenological, basic quantum), I do not seem to find it when I google =( My Aim is just to understand van der Waals binding in solids a little bit more.

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...

Well I am doing a project suffice to say on electron transfer. In protein complexes it has been shown that förster equation gives pretty good results, so I am trying to understand this equation. But there seems to be not much resource on that (I think I will be buying Förster's own book...

Hi , I crashes myself with this problem about diploe. Please can I have some suggestions. Assume that the density of water is 1000 [kg/m3] and that there are 3.34 × 1025 molecules per kg of water. (One mole of water weighs 18.0[g] since atomic weight of water is 18.0. A mole contains a...

I am rather confused about "dipole moment" in classical electromagnetisim. Since I have no previous background in this field of physics, I find it hard to understand the Maxwell's equations and other equations that involve the concept of dipole moment. Could anyone explain this to me in plain...

Homework Statement Find the magnetic dipole moment of a spherical shell of radiu R carrying a uniform surface charge sigma, set spinning at angular velocity omega. Homework Equations \vec{m} = \frac{1}{2} \int_{S} \vec{r'} \times \vec{K} (\vec{r'}) da' The Attempt at a Solution So...

Homework Statement A phonograph record of radius R carrying a unifrom surface charge sigma is rotating at a cosntant angular velocity omega. Find its magnetic dipole momentHomework Equations m = int I \bullet da The Attempt at a Solution Need to find the current first well the sruface charge...

Griffith' E&M problem 3.28 page 151 Given a spherical surface of radius R which carries a surface charge \simga = k \cos\theta Calculate the dipole moment of this charge distribtuion well using this equation \vec{p} = \int \vec{r'} \sigma(\theta') dA' = \int Rk \cos\theta R^2...

This might be a fantastically stupid question, but does the photon has a dipole? I'm almost certain it doesn't since a dipole is formed when two charges of opposite sign are very close to one another (at least compared to the distance an observer is from them) and unlike say the neutron which...

For a current loop, the magnetic dipole moment is defined as i \int d\vec{a} Now, if I'm given a surface current 'K', how can I find the magnetic dipole moment? For example, if a disc of surface charge [itex] \sigma [/tex] is rotating with angular velocity [itex] \omega [/tex], what is it's...

Hi, I'm stuck on a certain question in a tutorial sheet, and would appreciate a nudge in the right direction. The problem is in one particular question to which I missed notes due to illness, and won't have time to copy up before they need handed in. The question is on dipole moments: The...

Hello, i have absolutely no clue on how to start this one: a sphere of radius R has a uniform volume charge density \rho. Determine the magnetic dipole moment of the sphere when it rotates as a rigid body with angular velocity \omega about an axis through its center. thanks for the help...

Certain molecules have built-in dipole moments. The dipole moment of water is unusually large: 6.1 x 10-30C.m. How does this account for the effectiveness of water as a solvent?

Magnetic Dipole Moment does not include the permeability of free space? Hi, The formula for a magnetic field in a current loop involves the permeability of free space. But the formula for the magnetic dipole moment which seems to represent the flux through a current loop does not...

Point charges -5.00 C and +5.00 C are separated by distance 3.20 m, forming an electric dipole. What is the direction of the electric dipole moment? From + to -?

Question: Consider 2 spheres of radius R and uniformly charged with density \rho, one positively, the other nagatively. The two spheres are particlely overlapping each other and their center are separated by a distance d (< 2R). Calculate the dipole moment of this system. What I have done so...