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Applications of electric dipole materials in the field of electronics?
Wiki User
∙ 15y ago
uses of dipole materials
Wiki User
∙ 15y ago
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Why is the direction of electric dipole moments from negative to positive and that of a magnets is south from south to north?
let me try to explain it this way. Suppose I have an electric dipole that is placed in an external electric field E(vector). Now, scientists try to calculate the energy stored in the dipole due to its position and configuration in the external field. When you learn about angular motion, you probably know this equation that describe the potential rotational energy : delta U = U(final) - U(initial) = (integral from θ(initial) to θ(final) of the torque) = ∫τ dθ Let's just skip the calculation to determine the energy. But what we really need now is how to find the torque in order to estimate U. From the figure above, you might see that we assume the field points from the left to the right, there fore it will exert a force on the two charges. For the positive charge, the force is to the right and for the negative charge, the force is to the left, but the charges attract each other.Thus they cause the electric dipole to rotate around an axis that is perpendicular to the page and pass through the centre of the line connects the charges. The torque vector is the cross product of the displacement vector (r) and the force vector (F) then τ = r X F = F*r*sin(θ) = F*(a)*sin(θ) (since we let a=r is half the distance from the negative charge to the positive charge and it's exactly the distance from the centre to each point charge) And the total torque is : (total)τ = τ 1(positive) + τ 2(negative) = 2F*a*sin(θ) But the electric force F = qE, we substitute it into the equation to get: (total)τ = 2qEasin(θ), rearrange it, we have : (total)τ = (2qa)E(sin(θ)) Since it's easy to calculate E and θ, we let E and sin(θ) out and group two quantity a,q and the coefficient 2 as one quantity called the electric dipole moment p So now, p = 2aq That's how we got the magnitude of the electric dipole moment. But there's a problem since we realize that the torque (total)τ and E are all vector quantities. So that means the electric dipole moment p must also be a vector quantity so that we can perform the cross product calculation. (total)τ(vector)= p(vector) X E(vector) Here we have two choices, one is p points from the negative to the positive and the other is the opposite. Let me remind you that since the electric field points from left to right, the e.dipole will definitely rotate clockwise The toque is the vector that lies along the axis of rotation and since we have an international convention that if it rotates clockwise, the angular velocity is negative and if it rotates counter-clockwise then the angular velocity is positive if I use the right hand rule to find the direction and sign of the angular velocity , i find that the angular velocity vector points into the page and because τ= I*(angular velocity), the torque must points in the same direction, which is into the page. It's very clear now that τ(vector) = p(vector) x E(vector). We find the magnitude by performing this calculation: τ = pEsin(theta) and determine the direction using the right hand rule . As we discuss earlier, τ(vector) points into the page and E is to the right, thus the only solution for the direction of the electric dipole moment vector is from the negative charge to the positive charge(not the opposite one)!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! This works well with different configurations, too. And with that, we have a complete definition of the electric dipole moment vector that would fit and be consistent with so many previous physics laws and equations. Good luck with this!!!
What is the difference between monopole antenna and dipole antenna?
Monopole is an antenna with just the radiating element where the ground of the transmitter is connected to an electrical ground which serves as an Image ground to the radiating element. Thus the name "mono" pole. Dipole is where the ground and the radiating elements are connected to two different elements where one is the radiating element and the other is the ground to the later. Thus the name "Di" Pole Cheers by zafran khan
How does yagi-uda antenna differ from a folded dipole a loop antenna and a helical antenna?
Wow, your question on how a yagi-uda differs from a folded dipole, a loop antenna, and a helical antenna relates very much to how does a lawn mower engine relate to a V-8. The principals in all the antennas remains much the same. So I will deal with them in the order asked. The Yagi in its simplest form consists of 3 elements. The center element is the driven element and is essentially a dipole. Behind it is a slightly larger element called a reflector which does just that, it reflects signals to and from the dipole and in front there is the smaller director which helps focus energy. This is a directional antenna with gain. The folded dipole goes back to the basic dipole except it has makes a full loop. They are just as about as long as regular dipoles. With the loop of wire out there, they tend to have a wider band width than regular dipoles - but are not as tolerant of being used at even multiples of their cut frequency as the wires tend to cancel out each other. Oh, btw, yagi's have been made using folded dipoles. You must use ladder line or a 4:1 balun on folded dipoles, with perhaps the exception of the terminated folded dipole which has a resistor where the two elements of the dipole come together. The loop antenna? Which loop? I assume you are talking the traditional loop and not the magnetic loop. The full loop is normally computed to be 1005/frequency=feet. While you could take the time to tune the antenna, it might just be easier to put in a balun and an antenna tuner. The main advantage of a loop over the previous reviewed antennas is that it does fairly well even though fairly close to the ground where the previous 2 antennas should be at least 1/2 a wave length up for good performance. Helical antennas are generally good for just one band. In fact, due to the loading they cause they are best if used on a single frequency as their feed line requires them to be provided the connecting feed the is the electrical equivalent of a 1/2 wave at that frequency of operation. This may work well at VHF and above as an entire band can be tuned satisfactory, but in HF it would limit you to a very small segment of the band. Helical antennas definitely are the lawn mower engines of the antenna world. Look up antenna elmer on your favorite search engine. You have entered into a world where there is still a lot homework left to be done.
What is the similarity between ice and water?
I will laugh if this is someone from Oriana's Chemistry class. If you are, put into your own words please ^ ^ Um. From what I have been able to figure out, the primary forces of attraction between both water and alcohol molecules is the hydrogen bond, which is largely responsible in each for the high boiling point. Each have London dipole-dipole reactions that are also involved. Despite, or perhaps because of, their similarities, alcohol and water don't mix well, because they tend to form a really complicated hydrogen "network".
How do you increase the range of a Wifi transmitter?
You can buy range extenders that work with the wireless router. Bestbuy has some belkin, d-link, netgear and some linksys ones. What I meant was something free. I've heard things like putting a pringles can over the antenna will increase the range. Is that true? If not, are there other things like that that would work? I have tried using cans as improvised "cantennas" over my wireless router's dipole antennas. The signal results were worse than without the cans. A cantenna must be built to the correct dimensions to provide any signal gain, and it replaces the entire antenna. An almost-free solution is to build a parabolic reflector for each of your transmitter's antennas, directing the signal only where it's needed. See http://www.freeantennas.com/projects/template/ The only materials needed are glue, tape, aluminum foil, and light cardstock (a file folder will do). Since the cardstock is "invisible" to your wifi devices, you can tape the left & right edges of the foil to the outside (convex side) of the reflector. When the reflector is bent into a parabola, having the foil on the outside will pull the foil smooth rather than crumpling it. Here's one I designed for specific antennas: http://24.106.181.178/geocorona/index.html A true parabola with the antenna in the correct focal point will precisely direct the radio signals from your wireless device (eg, laptop) to the antenna, and vice versa. A simple reflector such as a can or arbitrarily shaped foil will sometimes cause more interference than signal gain. For those with a Linux-based Linksys router, third-party firmware is available that will allow a capable Linux user to electronically boost the signal strength of the router, but this will not increase the router's ability to receive signals from the client devices it serves. A bi-directional amplifier for the 2.4 GHz frequencies is required to get a signal boost both ways. These amplifiers usually cost as much as the wireless router they boost.
What is ment by ferroelectricity?
Ferroelectricity is a property exhibited by certain materials where they can retain a permanent electric polarization even after the electric field is removed. This arises from the alignment of dipole moments within the material. Ferroelectric materials are used in various applications such as sensors, actuators, and non-volatile memory devices.
What is the angle between dipole moment and electric field in a electric dipole?
Zero Dipole would set itself such that dipole moment vector is along the electric field vector
What is difference between between electric dipole moment and magnetic dipole moment?
Magnetic dipole is due to two poles of magnet. Electric dipole is due to +ve and -ve charges of electric charges.
An electric dipole is placed in a nonuniform electric filedIs there a net force on the dipole?
yes, there is a NET field .electric dipole experiences a net field .(not in uniform E.Field)
When is the torque on an electric dipole in an electric field is maximum?
That would have to be when the dipole axis is perpendicular to the field.
You turn an electric dipole end for end in a uniform electric field.How does the work you do depend on the initial orientation of the dipole with respect to the field?
The work done by you to turn the electric dipole end for end in a uniform electric field depends on the initial orientation of the dipole with respect to the field. If the dipole is initially oriented such that its positive and negative charges are parallel to the electric field, then no net work is done as the electric field does not do any work on the dipole as the electric field lines do not transfer any energy. On the other hand, if the dipole is initially oriented such that its positive and negative charges are perpendicular to the electric field, then work is done by you to turn the dipole as the electric field exerts a force on the charges in the dipole in opposite directions, causing them to move in opposite directions. As a result, you have to do work to move the charges and turn the dipole.
Which orientation of an electric dipole in an uniform electric field would correspond to unstable equilibrium?
So interesting query! As we keep the dipole with its dipole moment along the direction of the electric field then it will be in stable equilibrium. IF we keep the same dipole inverted ie its dipole moment opposite to the external field then the dipole will be in unstable equilibrium.
What is the expression for the electric field in the perpendicular bisector plane of a dipole?
expression for the electric field in the perpendicular bisector plane of a dipole
Which orientation of an electric dipole in a uniform electric field would correspond to stable equilibrium?
when angle 0 b/w dipole moment vector p and electric field vector E is zero then potential energy of dipole, U=-pEcos0 =-pE and torque=pEsin0=0;which means that the electric dipole is in stable equilibrium.
What is two opposite electric charges separated by a short distance called?
dipole dipole
What is the total charge on an electric dipole?
Q1:How to calculate electric potential due to a dipole? Q2:How to calculate electric potential due to ring of charges? Q3:How to calculate electric potential due to charge disk? Q4:how to calculate electric potential due to a quadrupole?
How electric field is equal to force by dipole moment?
when dipole moment,torque and electric field all the three are perpendicular to each other.
