Dielectric Definition and 676 Threads

Homework Statement A point charge q is a distance d from a dielectric half-space (z < 0). We will solve for the potential outside of the dielectric, in the region z > 0. (a) Away from the point charge, what equation does V satisfy? Find the bound- ary conditions at the dielectric...

When a dielectric is inserted between the plates of a parallel plate capacitor , what would happen to its charge , Q and electric potential , V as compared to when there is no dielectric ? My thoughts are the presence of dielectric cause the resultant electric field to decrease , and from...

A derivation of the capacitance for a parallel plate capacitor is as follows: [ assume uniform field, plate area is infinite in relation to the separation, the conductors are perfect conductors ] So, V=Ed where V=voltage difference between plates E= electric field (uniform)...

Homework Statement A coaxial cable of circular cross section has a compound dielectric. The inner conductor has an outside radius a , which is surrounded by a dielectric sheath of dielectric constant K_1 and of outer radius b . Next comes another dielectric sheath of dielectric constant...

Can anyone explain the concepts behind dielectric material inside a capacitor. Why is the capacitor able to store more charge exactly? Thanks!

Homework Statement Fig. 1 and 2 show a dielectric slab being inserted between the plates of one of two identical capacitors, capacitor 2. Select the correct answer to each of the statements below (enter I for `increases', D for `decreases', or S for `stays the same'). 1. In Fig. 2...

Homework Statement Say, i have a setup as shown on the photo below http://www.flickr.com/photos/47719498@N07/4375079183/ * setup also seen as attachment how can i be able to compute for the dielectric constant provided it is not parallel plate and considering two different area is...

A parallel plate capacitor of capacitance 10microfarads has the space between filled with material with (dielectric constant k)= 4.0. The capacitor is charged to a potential difference of 2.0V . With the capacitor connected to the battery the dielectric is removed. 1. The capacitance is F...

Homework Statement You are an intern at an engineering company that makes capacitors used for energy storage in pulsed lasers. Your manager asks your team to construct a parallel-plate, air-gap capacitor that will store 120 kJ of energy. (a) What minimum volume is required between the...

Hello, I am looking to purchase Dielectric couplings. I am located in the east coast (NY/NJ). I am having trouble finding these, any help is appreciated. Does anyone know any businesses who sold these during the mid 1990's ?

Homework Statement A medium is described by the response functions \varepsilon (\omega ) and {\mu ^{ - 1}}(\omega ) in \textbf{D} = \varepsilon (\omega )\textbf{E}, \textbf{H} = {\mu ^{ - 1}}(\omega )\textbf{B}. Construct the equivalent dielectric tensor {K_{ij}}(\omega ,\textbf{k}) in...

Hi Got a question, hoping someone can give a good explanation for. We all know that large static uniform electric fields have the potential to ionize. (Dielectric breakdown of Air - Static Electricity Shock). In the Quantum picture, why does this occur. Take for instance the photo...

Homework Statement Two identical capacitors are connected in parallel, charged by a battery ov Voltage V, and then isolated from the battery. One of the capacitors is then filled with a material of relative permittivety E. Homework Equations What is the final potential difference...

Homework Statement A cavity can only store 1J of EM energy as it reaches dielectric breakdown at 3kV/mm. What dielectric strength would a new gas filling the cavity have if the energy stored was to be 4J. Homework Equations U=\frac{1}{2}(epsilon)E2The Attempt at a Solution I would use the...

I know it has to do something with the Breakdown voltage but I've looked everywhere on my book and i have no idea how to calculate it.

What's the formula to calculate it, I've looked everywhere.

What is happening to a ray of light of a certain wavelength that passes through a transparent dielectric medium? Ex: Green light enters in a Bose–Einstein condensate, and slows down some. Than the light is coming out of the medium in free space. What will be the speed of the ray light and...

im confused about what a dielectric sphere is. I have tried googleing it but i couldn't find anything that useful, please help

I understand that Dielectric Strength relates to the point where a compound breaks down under electrical load. Please correct me if I have it wrong. I want to now if an RTV compound (with Dielectric Strength of approx 500 volts/mm) is safe to use across 240v or 415v terminals that are 3-5mm...

i am reposting this question , earlier it had been deleted assuming it to be a "HOMEWORK QUESTION" , well my question is , can we define a dielectric constant for a conductor ?? is it conceptually meaningful?? if yes then why and what is it?

Homework Statement A dielectric interface is defined as 4x + 3y = 10 m. The region including the origin is free space, where D1 = 2ax - 4ay + 6.5az nC/m2. In the other region, εr2 = 2.5. Find D2 given the previous conditions. Homework Equations an12 = ± grad(f)/|grad(f)| D2n = D1n =...

Homework Statement A square parallel plate capacitor with vertical plates of area A and distance d, charged with a constant charge Q and is completely filled with a dielectric material the same dimension as the gap between the plates, with dielectric constant k and mass m. Assuming the...

Homework Statement I must calculate the capacitance of the following capacitor : A cylindrical capacitor made of 2 shells (not sure if shell is the right word in English. Made of 2 cylinders maybe), one of radius a and the other of radius b>a. It has a length of L. We introduce entirely...

Homework Statement A uniform charge q is distributed along a sphere of radius R. a) What is the Electric Potential in the center of the sphere? Homework Equations V(r1)-V(r0) = - \int \stackrel{\rightarrow}{E} * \stackrel{\rightarrow}{dl} The Attempt at a Solution

Homework Statement I have a linear dielectric material. The electric field in the material is 38% less than a vacuum field with the same external sources. I need to find the susceptibility of the material? Homework Equations I used P=\epsilon\chi(vacuum)E P=\epsilon\chi(material).62EThe...

A point charge inside infinite dielectric material 1. The problem statement, all variables and given known data A point charge is an infinite medium of dielectric material having a relative permittivity \epsilonr. <--- epsilon(sub r). Find the electric field vector and the potential function...

Homework Statement A very long cylinder of liner dielectric materil is placed in an otherwise uniform electric field E_0 . Find the resulting field within the cylinder. (the radius is a , the susceptibililty \chi_e and the axis is perpendicular to E_0) Homework Equations The Attempt at a...

Homework Statement "When a block of insulating material such as Lucite is bombarded with high-energy electrons, the electrons penetrate into the material and remain trapped inside. In one particular instance a 0.1 mA beam bombarded an area of 25cm^{2} of Lucite (Class A: \epsilon_r=3.2) for 1...

Homework Statement A conducting wire carrying a charge \lambda per unit length is embedded along the axis of the cylinder of Class-A dielectric. The radius of the wire is a; the radius of the cylinder is b. Show that the bound charge on the outer surface of the dielectric is equal to the...

Homework Statement An isolated metal sphere of radius a has a free charge Q on its surface. The sphere is covered with a dielectric layer with inner radius a and outer radius b Calculate the polarization charge density on the inside and outside of the dielectric. Homework Equations...

Holy Dielectric! Homework Statement A large block of dielectric contains small cavities of various shapes that may be assumed not to disturb appreciably the polarization. Show that, inside a needle-like cavity parallel to P, E is the same as in the dielectric Homework Equations...

1. Find the electrostatic energy of a neoprene sphere or ratio R, charged with Q if: a) Q is uniformly distributed in surface The Attempt at a Solution So, I can calculate the displacement field (so that I can use the expresion U= \int \vec{D}.\vec{E} dV), but only for those points in...

I've been working on this for a little while now (in CGS units), and am not really sure where I've gone wrong at in calculating the potential, so I've come here! Here is the problem: What is the potential caused by placing a point charge Q at the center of a dielectric sphere (\epsilon2)...

Homework Statement A liquid-level transducer consists of two parallel plates of conductor immersed in an insulating liquid. When the tank is empty the capacitance of the plates is 200pF. The relative dielectric constant of the liquid is 25. Determine an expression for the capacitance C as a...

Homework Statement A slab of copper of thickness b = 1.85 mm is thrust into a parallel-plate capacitor of plate area A = 2.25 cm2 and plate separation d = 5.00 mm, as shown in the figure; the slab is exactly halfway between the plates. What is the capacitance after the slab is introduced...

We have an infinite half-space filled with a dielectric. The other half-space is vacuum. We take a sheet of charge of density \sigma and place it on the surface of the dielectric. What are the D & E fields everywhere? We clearly have D_1 + D_2 = \sigma. But what other equation do we have? Can...

Homework Statement Either Coulomb's Law or Gauss' Law and r>R, I get \textbf{E}=k\frac{Q}{r^{2}}\textbf{r}. Q is the total charge. If R is the radius of the sphere, shouldn't the field at a point a<R simply be k\frac{Qa}{R^{3}}? Inother words, the field is proportional to the enclosed...

How to calculation the potential distribution for a dielectric cylinder placed in electric field of point charge? The height of the dielectric cylinder is H, while its section radius is R. The dielectric constant of the cylinder is ε1...

Hi everyone, My very first post after simply using physicsforums as a (very) handy FAQ resource. Okay, so my question is probably pretty simple, but I've been unable to find anything on here already. How does a complex dielectric constant imply the absorption of EM radiation? I...

friends, can anyone explain me the effect of electric field on a dielectric(non- conducting) medium

Hello all of you! I'm looking for reliable data about the dielectric strength (=breakdown field) of liquid insulators with a high permittivity and a low viscosity and not too dangerous. Examples of such liquids: - Ethylene glycol carbonate. Propylene glycol carbonate. Maybe the oxalates...

Hi everyone, this is not a homework, I'm actually dealing with the case in real life here. If this turns out to be standard textbook stuff then I'm sorry as I haven't studied this before. Suppose a plate capacitor has two different dielectric material layer sandwiched in it. Then a fixed...

A capacitor is constructed commercial wrap two sheets of aluminum separated by two sheets of paper coated with paraffin. Each aluminum foil and paper has width of 7cm. A sheet of aluminum has 4x10^{-6}m and thickness of paper is thick 25x10^{-6}m and a dielectric constant of 3,70. What is the...

Homework Statement When a certain air-filled parallel-plate ca- pacitor is connected across a battery, it ac- quires a charge (on each plate) of magnitude 214 μC. While the battery connection is maintained, a dielectric slab is inserted into the space between the capacitor plates and...

Homework Statement Two flat metal circles of radius r=15 mm are brought a distance d=8.0 mm apart to form a parallel plate capacitor. The surface charge density of one plate is measured to be +1.0*10^-3 microCouloubs/mm^2. The potential difference across the capacitor is measured to be .12...

Let me know if the following reasoning is correct : If the surface charge density on the internal surface of one of the plates in a parallel plate capacitor is Sigma, which becomes Sigma/K, when a dielectric material is inserted between the plates with dielectric constant...

Higher dielectric constant means better insulator. Water has a dielectric constant of 8, which is enormous(according to Walter Lewin), but it still is a very good conductor of electricity, why?

can you please tell me, how do we measures the conductivity and dielectric constant of silicone oil and castor oil, because resistivity of silicone oil is very high so that's why it is difficult to mesure with conductivity meter,

Hello All, I am wondering why the presence of a dielectric reduces the potential difference of a capacitor (after having been separated from its energy supply). I understand how it works, based around maintaining the same charge, I just don't see why. Thank you for the Help.

assume that i have a cloud of cold dilute Rubidium atoms i know the atomic levels of the Rubidium atom How to calculate the dielectric constant of this gas? Which book can i consult?