Dipole Definition and 796 Threads

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...

Homework Statement Two electrical dipoles with dipole moments \vec{p}_0=p_0\hat{y} and \vec{p}_1=p_1\hat{y} are located in the xy-plane. \vec{p}_0 i located at the origin and \vec{p}_1 is initially in (x,y)=(a,0). What work is required to move \vec{p}_1 (with unhanged directon) to the point...

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.

Homework Statement This is a mastering physics question but it does not count for my assessment mark, i am using an alternative approach to the one given in the hints. And off course i got the question wrong but i don't understand why.. "[URL...

I was hoping people might be able to provide some insight into the following fairly basic scenario (not homework/school related). Imagine a positive point charge on the x-axis. Also on the x-axis, to the right, is an electric dipole, with finite spacing, pointed along the x axis, with the...

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...

Homework Statement The graph shows the potential energy of an electric dipole which is in a constant electric field; only the electric force is acting on the dipole. Consider a dipole that oscillates between plus and minus 65 degrees. a) What is the dipole's mechanical energy? b) What...

Homework Statement The figure shows an electric dipole. What is the magnitude of the dipole's electric field at point P, located at distance r >> d? Homework Equations The Attempt at a Solution I suppose I could define the angle with which I could write Ey = Esin\theta, but...

Hy, i am back with my annoying questions about this and that. Could everyone tell me why the frigging dipole have an electric field that drops with 1/r^3? i mean, if i am far away , i should feel no electric field, you know, q2 = -q1 , so they cancel, but i feel (q1 q2 k)/r^3.What the HECK?

Homework Statement Two dipoles are oriented as shown in the diagram below. Each dipole consists of two charges +q and -q, held apart by a rod of length s, and the center of each dipole is a distance d from location A. If q = 4 nC, s = 1 mm, and d = 6 cm, what is the electric field at location...

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...

Hi all: One system consists of two neutrons. both spin magnetic moments are 1/2. At a instant time, neutron 1 locates position 1 and neutron 2 is in position. As we know, spin magnetic moment is kind of dipole moment. They can generate magnetic field (not electric field). The interaction can be...

microwave can be used to engineering potentials for alkali atoms i find that in the literature, people only take the magnetic dipole transition into account why the electric dipole transition is neglected? is it forbidden?

Homework Statement I wonder if anyone could explain me how to arrive at the equation (1.24). I have attached the part of the book where this appears. Homework Equations I have attached the part of the book where this appears. The Attempt at a Solution I have tried to make the...

Homework Statement A dipole of moment 0.7 e * nm is placed in a uniform electric field with a magnitude of 50000 N/C. Find the potential energy of the dipole in the electric field at 60 degrees. Answer in units of J. Homework Equations -pE cos (theta) The Attempt at a Solution I...

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...

In Weinberg's cosmology book, section 2.4 we have T' = \frac{T}{\gamma(1+\beta\cos{\theta})} He then claims, "Expanding in powers of beta, the temperature shift can be expressed as a sum of Legendre polynomials" \Delta T = T' -T = T\left(-\frac{\beta^2}{6} - \beta P_1(\cos{\theta}) +...

As per my understanding, the position of most stable equilibrium of a dipole placed in a uniform electric field is when it is aligned with the field, i.e. when E and p (dipole moment) are in the same direction. Also the position of most unstable equilibrium is at the position where the dipole...

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...

In the near field, a hertzian pole has a changing electric field and a changing magnetic field, that are in both space and time quadrature. Are two sets of EM waves then created in the far field, one from the changing e-field, and one from the changing m-field?

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...

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

Was studying in class the effects of the E and B fields far from the source and what they looked like, but we failed to discover what happens near the source...Is this because there is no difference or did we just not cover the material

Homework Statement Hey everyone, I need to derive what the E and B fields look like for the electric dipole in the near field region close to the source i.e. lambda>>r. Homework Equations The Attempt at a Solution I managed to derive it for the situation far from the source but...

Homework Statement In Figure 21.12, two point charges q1=3uC and q2=-3uC interact with a third point charge Q=7uC. Find the magnitude and direction of the total (net) force on Q. Homework Equations Edipole= kqs/r^3 The Attempt at a Solution I solved for the electric field with the...

Dipole in an Uniform Electric Field: torque is calculated about the position of either charge has the magnitude FLsin(x) = qELsin(x) = pEsin(x). The direction of the torque vector is into the paper such that it tends to rotate the dipole moment vector p so it aligns with the direction of E. The...

Homework Statement Dipole in an Uniform Electric Field: torque is calculated about the position of either charge has the magnitude FLsin(x) = qELsin(x) = pEsin(x). The direction of the torque vector is into the paper such that it tends to rotate the dipole moment vector p so it aligns with...

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...

I am looking for a reference (derivation) for this exact formula given for "the magnetic field due to a dipole \mu fixed at the origin" : B=-\frac{\mu}{R^3}+\frac{3r(\mu\cdot r)}{R^5} I don't really know anything about dipoles or how they are derived (I have only taken lower division E&M)...

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...

optical diple trap is used to trap spinor bec i have a question why are the three different atomic internal levels feel the same shift? To calculate the energy shift of a specific internal level, we need to find out the coupling between this level to higher levels. For different levels...

Homework Statement Find the value of the dipole moment of the distribution of charges. -2q on top of equilateral triangle +q on each of the other points. Each charge is separated by distance d. Homework Equations p = \sum (q_i)(r_i) The Attempt at a Solution p =...

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...

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...

Homework Statement a dipole, \vec p , is in a non uniform field, \vec E = (E) \vec i where \vec E points along the x axis. What is the net force on the dipole if \vec E depends only on x?Homework Equations | \vec{p} \times \vec{E}| = | \vec p | | \vec E | sin \theta The Attempt at a...

Homework Statement Show that the magnetic field of a dipole can be written in coordinate-free form: B_dip (r)=(μ_o/(4πr^3 ))[3(m*r ̂ ) r ̂-m] Homework Equations Adip(r)= (μ_o/(4πr^2))(m*sin(theta))...

Homework Statement Suppose a point dipole is located at the centre of a grounded spherical conducting shell. Find the potential and electric field at points inside the shell. (Hint: Use zonal harmonics that are regular at the origin to satisfy the boundary conditions on the shell.)Homework...

Homework Statement I got this problem from my physics textbook, and I'm not sure how to solve it. A point charge R is distance p from the center of a diple consisting of charges + and - q separated by distance s. The charge R is located in the plane that bisects the dipole. What is...

Homework Statement A point charge Q1 is distance r from the center of a dipole consisting of charges +/- q2 separated by distance s. The charge is located in the plane that bisects the dipole. At this instant, assuming r>> s, Part A: what is the magnitude of the force on the dipole? Part B...

i know that the strongest bond is between metal and non-metal like NaCl after it comes the hidrogen bonds which H bonds with N or O or F after that comes the dipole- dipole bond i don't know how to recognise it regarding what substances and how they look after that comes dipole-...

Homework Statement I'm working on a homework problem which requires me to roughly sketch electric field lines. The object on the left is neutral and grounded, the object on the right was just struck by lightning (and therefore very negatively charged) and I assume that the neutral object in...

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

An electric dipole consists of a pair of point charges each of magnitude 4nC separated by a distance of 6cm. What is the electric field strength at the point midway between the charges? Not sure what equations to use? Any ideas?

Homework Statement Show that a line of charge density \lambda exerts an attractive force on an electric dipole with magnitude F = \frac{2\lambda p}{4\pi\epsilon_{0}r^{2}}. Assume that r is much larger than the charge separation in the dipole. Homework Equations I need to show that the...

I've been trying to learn the details of electromagnetic radiation from a hertzian dipole antenna, but all the information that I find only gives me a patchy understanding. This is what I have so far: Near-Field: Charges oscillate past each other in a center-fed hertzian dipole. This...

Hi guys, I'm in my final year of my physics degree and for my first semester project I had to make a dipole radio antenna, and it's proven to be quite tricky (at least in the theory side of things). I would seriously appreciate some help with a few things if anyone has anything to offer :)...