Dipole Definition and 796 Threads

[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...

Homework Statement An ammonia molecule (NH_3) has a permanent electric dipole moment 5.0 * 10^-30 Cm . A proton is 2.50 nm from the molecule in the plane that bisects the dipole. What is the electric force of the molecule on the proton? Homework Equations E_dipole = K 2p / r^3 (on axis...

What is the basis for the sixth root dependancy on the inverse of the distance between the dipoles (in any dipole-dipole interaction)? Is it empirical or can it be mathematically derived?

do the electrons have spin angular dipole momentum? (In classical mechanics, the spin angular momentum of a body is associated with the rotation of the body around its own center of mass) Thank you.

Homework Statement #3 on this PDF Homework Equations \tau = Frsin(\theta) = I \alpha I=mr^2 The Attempt at a Solution Here's what I've done: \tau = Frsin(\theta) = I \alpha F=QE 2QEsin(\theta) \frac{A}{2} = 2M\left(\frac{A}{2}\right)^2 \alpha simplify: QEsin(\theta)A =...

is there a relationship between the two? its been bugging me for a while. can't find the answer.

We know that same charges repel and opposite attract them selfs. So if the electrons have dipole magnetic momentum, how will they repel, if they get closer with their opposite poles of the dipoles? Thank you.

Homework Statement Show that the electric field from an electric dipole for r>>d is: \vec{E} = \frac{Qd}{4\pi\epsilon_0 r^3}(2\cos \theta \hat{r} + \sin \theta \hat{\theta}) Homework Equations Electric Field of a Point Charge: \vec{E}=\frac{Q}{4\pi\epsilon_0r^2} The Attempt at 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 For this problem, I had to find the fractional charge given the dipole moment u and bond length R in a diaomic molecule (H-X, where X is a halogen)... I found that fractional charge by: fractional charge=u/(eR) where e=elementary charge of an electron I think that's...

(This question doesn't apply to a specific problem, hence I'm not using the template.) Consider a dipole, approximated as a "dumbbell": two oppositely-charged spheres (charges of equal mag.) connected by a rod (that is, the chemical bond). Suppose that I know the dipole moment. If this dipole...

How is possible that the magnetic field around electron is dipole but it's one circle? Best regards. p.s thanks for the help.

When I got a stick with opposite electric charges on both ends ( a macroscopic dipole) and start slowly spinning it, I get radio waves. What happens when I keep increasing the spinning velocity, do I get the whole spectra of em waves? Does the dipole send out light at a certain spinning...

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...

Hi, in my notes for the Hertzian Dipole I have a derivation of the vector potential A, and the scalar potential (phi). However, I'm missing the derivation of the E and B fields from these potentials. It seems that only the theta component of the E field exists, and I have ... well, I can't write...

Homework Statement Since the electrostatic field is conservative, show that it is irrotational for an electric dipole, whose dipole momentum is p .Homework Equations \nabla \times \mathbf{E} = 0 The Attempt at a Solution I know that the components of the electric field in spherical...

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...

Problem Diagram (Ignore the tildes, they're just placeholders): Below: An electric dipole ~~~~~~~y-axis~~~~~~~~~~~~~~~~~~ ~~~~~~~|~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~|~~~~~~~~~~~~~~~~~~~~~ ~~~~~~~|~~~~~~~~~~~~~~~~~~~~~ ~~<---a---> <---a--->~~~~~~~~~~~~~~~ +Q --------- X ---------...

dipole torque problem.. Help please! Hi, the problem is: Show that if the force action on a dipole p placed in an Non uniform electric field is p\cdot \nabla E_{ext}, the torque acting on the dipole in this field is \tau =r \times (p\cdot\nabla E_{ext})+p\times E_{ext} where r is the...

let's say we have an electron circling the nucleus (like the bohr's hydrogen atom), i don't understand why the average wrt to time of the moment of the diople is zero? we have this equation: \frac{\int_{0}^{T}pdt}{T} well obviously the diople, p, is constant throughout the elctron's motion...

[[disclaimer: this is *not* a homework assignment]] In general relativity, the lowest non-vanishing multiple of gravitational radiation is generically the quadrupole: the monopole is forbidden by Birkhoff's theorem, and conservation of momentum is forbidden by conservation of momentum. I...

We have an electric dipole. Now, let us draw a Gaussian surface around our electric dipole. Now, the total charge enclosed by our Gaussian surface is zero, so according the Gauss' Law the flux through the Gaussian surface is zero, and so is the electric field intensity due the electric dipole...

a- I place a ferromagnetic dipole in a uniform magnetic field so that the axis of the dipole moment vector does not lie parallel to the magnetic field lines. Is there a net force on the dipole? Is there a net force? b- I place a ferromagnetic dipole in a uniform magnetic field so that the axis...

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...

This isn't a homework problem, I'm just doing this as practice. Homework Statement A magnetic dipole is oriented in a loop of wire of N turns and radius a so that the dipole vector is parallel to the normal of the loop. The loop is connected to a galvanometer, and the active resistance of...

this is not homework help.I want to know. Hello,can anyone suggest why for a dipole m placed in a magnetic field B F=grad(m.B) and N=mxB?

"paradox" regarding energy of dipole orientation I've ran into a "paradox" concerning deriving the energy of a dipole's orientation in an external field. For example, the energy of a magnetic dipole m in an external field B is known to be: U= - \mathbf{m} \cdot \mathbf{B} In Griffiths...

Hi all, I want to generate the dipole vector for a water molecule. I start by generating the dipole moment of the molecule by the formula \mu = \sum Q_a * R_ab but I don't know how to generate the dipole vector? Any help appreciated. Thanks in advance

The energy of a magnetic dipole in an external magnetic field is U = - \mathbf{m} \cdot \mathbf{B} Yet if I try to show this by calculating the energy in the fields, I get the wrong answer. I believe the problem is that I am making some arguements which neglect strange behavior at r=0, and...

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 1) In the case of a bar magnet, outside it, the magnetic lines of forces start from North Pole and end on South Pole. But inside it, the lines of force start from south and end on North Pole. According to definition of direction of lines of force, it is the direction in...

Homework Statement Two point charges likes those in the figure below are called an electric dipole. Show that the electric field at a distant point along the x-axis is given by E_{x}=\frac{4k_{e}qa}{x^3} Figure: http://img300.imageshack.us/my.php?image=58ag9.png Homework Equations...

I am having some problem with the formulas for calculating the electric fields of an infinite line of charge and an electric dipole. I don't understand conceptually why they are the way they are. Can someone explain? Any help is appreciated! [Note: K=1/(4*pi*epsilon_o), lambda=linear...

Homework Statement You've got a circular loop with a steady current I and radius 'a' a distance r from a square current carrying loop with sides of 'b' and current I, r >>> a or b(and they're arranged in such a way as you can think of the circular loop's dipole as pointing up, and the square...

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...

In a review question, we are asked to consider a particle of mass m and charge q in a 1-D harmonic oscillator potential V(x). Light is shined on the harm. osc. with E-field E=E_{o}cos((\omega)t-kx), where k=\omega/c. (Fine, so far. It seems like a Rabi frequency problem, similar to an Ammonia...

Homework Statement A sphere of radius R and uniform charge density 'row' is situated at the origin. A uniformly charged line with length L and charge density 'lamda' (for simplicity assume L>2R) is a distance D from the origin in the y=0 plane and orientated so as to be parallel to the x-axis...

Griffith's E&M problem 4.5 page 165 In the figure p1 and p2 are perfect dipoles a disantce r apart. What is the torque on p1 due to p2.? Wjat is the torque on p2 due to p1? the second part is done in post #4 p1 is located on the right pointing upward p2 is a distance r from p2 and is...

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...

Hello there, I know that folded dipole is used ofr a good matching in antenna systems. Is there a freqeuncy range for them to be used more efficiently? Or can we use both of them in the similar freqeuncy ranges?

Two point charges 3q and iq are spearated by distance a as in the diagram. Find the monopole, dipole moments and the approximate potential at large (in spherical coords including both dipole and monopole contributions) monopole moment is sum of charges 3q \hat{k} + qa \hat{k} = q(a+2) \hat{k}...

It can be shown that if a hamiltonian is invariant under space inversion and if an eigenstate is non-degenerate, then the state is either even or odd in each position coordinate. So if there is a perturbation given by a uniform electric field, which has: H_1 = - \vec E \cdot \left( \sum_i q_i...

I'd like to check my thinking which is getting fuzzy: Question: Two particles are fixed to an x axis: particle 1 of charge q1 = 2.91 x 10-8 C at x = 26.3 cm and particle 2 of charge q2 = -5.82q1 at x = 46.6 cm. At what coordinate on the x-axis is the electric field produced by the particles...

In chapter 10 section 3 volume 2 of the Feynman lectures on physics, there is a passage that I can't force myself to agree with. He says, talking about the polarization vector of dielectrics, Can someone explain this perhaps differently? I really don't see how a non-uniform polarisation...

Hi; Can somebody solve this question below? (i found some answers but I'm not sure of them) TY for your interesting..

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...

A simple electric dipole in an external magnetic field performs harmonic motion (for small angles between E and L) due to the moments by the forces acting on the respective charges. Assuming there is no system to dissipate energy that is. The mechanic moment is given by p x E and the energy of...

Hey! My teacher gave me a very challenging problem on QM. I've only had one introductiary course, but he said he wanted me to figure this problem out by using whatever resources, so now I turn to you guys ;-). The problem is the following: London attraction forces can be thought of as...

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...