# Questions tagged [dipole-moment]

Dipole moment is the electrostatic moment generated by two opposite charges taken together, far away from the charge's locations

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### Absorption Cross Section for Two-Level Spin System in an AC Magnetic Field - Photon Picture

For a two-level spin with a energy difference of $E = h f$, where the two levels have zero dipole electric coupling and can only be driven by a magnetic field, how do I calculate the absorption cross ...
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### Meaning of electric dipole moment

what is the meaning of electric dipole moment? Or why do we need to define electric dipole moment?
1 vote
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### Intuition for magnetic dipole moment

The definition of the electric dipole moment of a system of charges makes sense intuitively - $$\boldsymbol {\bf p} = \int_{V} \boldsymbol {\bf r} \rho (\boldsymbol {\bf r})dV$$ describes the overall ...
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### Multipole expansion, same charges

I know dipole is defined with 2 opposite charges. That's why in EM dipoles exist, while in gravity they do not. However, I view multipole expansion as a way to describe how the distribution of charges ...
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### Understanding polarization and magnetization intuitively?

I am trying to develop a more intuitive understanding of the field produced by magnetization and polarization. I have the following image, and I can derive it from Maxwell's equations what the fields ...
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### Dipole moment and Branching ratio relation

I am looking for a good derivation of relation between dipole moment of transition and Branching ratio of the transition, is there a good textbook for this?
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### Larmor precession with an oscillating field?

With a non-polar molecule like CO2, presumably Larmor precession doesn't apply. However, CO2 has a mode of vibration that induces an oscillating dipole moment. Could something similar to Larmor ...
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### What does centre of mass of charge mean?

I am unable to understand what does this centre of mass of positive charge and centre of mass of negative charge mean??
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### What does centre of positive and negative charge separated by a small distance mean? [duplicate]

I dont understand the meaning of this statement that centre of positive and negative charge is separated by a small distance??
1 vote
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### Why do we make a dipole a ideal dipole?

My question is that why do we make a dipole a ideal dipole ($q\to\infty$ and $d\to 0$) …i mean i want the reason behind to take this and what is the problem of taking a charge with some magnitude (not ...
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### Density of current in a Elementary Dipole

I can't understand this formula from my textbook, I'm trying to understand why the Density of Current is I*ΔZ(ΔZ is the lenght of the dipole) i mean a density of current would be I/Δs (with Δs the ...
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### How do i determine the dipole moment of a charged conducting sphere in a uniform electric field?

What bugs me the most is that since there is net charge, i dont know two things, how would that charge distribute across the surface (even though my intuition says that one of the sides will have more ...
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### If torque is a form of moment, then why is the word 'moment' used for the 'magnetic dipole moment', NiA, for a current-carrying loop?

I thought torque is a form of moment: If the moment makes the object rotate, we call it torque; otherwise we just use the name moment. However it seems the electric & magnetic dipole moments are ...
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### Has been the spin magnetic dipole moment value of the free electron to be Lorentz invariant ever experimentally verified?

As far as I know all experiments measure the rest value of the spin magnetic dipole moment of a free electron either indirectly at relativistic speeds near the speed of light measuring for example the ...
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### Is the spin magnetic dipole moment of the free electron not at rest the same as its rest value?

As far as I know all experiments measure the rest value of the spin magnetic dipole moment of a free electron indirectly (i.e. apparently there is yet no method or apparatus to directly measure this ...
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### Does an initially accelerating electron introduced inside a homogeneous magnetic field reduces its spin magnetic dipole moment?

Due to the Lorentz force we know that such an electron will be forced to a helical forward trajectory and given enough time inside the magnetic field it will experience also a continuous diminishing ...
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### What would it mean for a dipole moment not to be constant?

It is fairly easy to show that, for a neutral the electrostatic force on a neutral charge distribution with a dipole moment $\bf{p}$ is given by $\bf{F}$$=$$(\bf{p}$$\cdot \nabla)$$\bf{E}(r)$ if we ...
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### Work done in bringing a test charge from infinity to center of dipole

Potential at Equatorial point of dipole is given 0 in my book(after putting angle = π/2 and cos(π/2) = 0 in formulae V = (K p cos(x)/r2) x = angle made my ...
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### Question regarding understanding Dipole Moment

I am trying to understand the meaning of the term Dipole Moment,every definition or physical explanation involves some kind of hand wavy explanations ,I would like some concrete intuitive explanation ...
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### Quadrupole moment being tensor in electromagnetism

I was reading "Lectures on Electromagnetism" by Ashok Das and he says that because the moment of a monopole is a scalar, the moment of a dipole is a vector then the quadrupole moment is a ...
1 vote
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### What kind of experiment could measure the total sphericity of the electron's monopole charge $E$-field? [duplicate]

As far as I know this was never experimentally undertaken with a high precision measurement, probably by measuring the $E$ interaction field around the monopole charge of an isolated electron (i.e. ...
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### Why magnetic field doesn't do any work on moving charge?

As we know the Lorentz force $F=qv\times B$ never does work on the particle with charge $q$. But it does work on a dipole. My question is, doesn't a moving charge behaves like a dipole? I mean an ...
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### Can we calculate dipole moment about infinity?

If $Q_{net}$ is zero: can we calculate dipole moment about infinity? if yes, is the dipole moment the same as about origin dipole moment is calculated?
If I have two molecules with different constants polarizabilities $\alpha_1$ and $\alpha_2$ and I send and EM field first on the molecule no.$1$ and then on the molecule no.$2$ so that the two ...