Dielectric Definition and 676 Threads

Homework Statement A slab of dielectric of thickness a and relative permittivity ε is placed in a uniform external field E whose field lines make angle θ with normals to the surface of the slab. What is the density of polarization charge on the surface of the slab? Neglect end effects...

Hello! Let's consider a plane wave represented by a ray, propagating in a 2D dielectric slab. It has a medium with refractive index n_1 as its core and a medium with refractive index n_2, n_2 < n_1, as its cladding. In order for this ray to represent a mode, it must satisfy two conditions: -...

Homework Statement there's a paper insulated plate capacitor. a.) What should the area of the plates be when the capacitance is 0,1 μF. thickness of the paper in between the plates of the plate capacitor is 0,05mm the relative permittivity of the paper is 2,5 b.) How big of a charge can be...

Is the potential across the boundary continuous for a dielectric sphere embedded in a dielectric material, so that the potential inside the sphere can be set equal to the potential outside of it at r=R ?

Homework Statement A dielectric sphere of radius R with uniform dielectric constant ε has an azimuthally symmetric density charge σ = σ0 cos θ placed on the surface. Outside the sphere is vacuum. (a) Obtain the electrostatic potential inside the sphere, φin. (b) Obtain the electrostatic...

I'm constructing a device that needs two electrodes in a mesh-like formation. there doesn't have to be a cavity but one is preferred. I have this https://imgur.com/a/DWoxQ But I need there to be insulation like on a normal wire. I'm looking at a wire gauge of 28+ AWG. Ive tried 3D printing a...

Hey SIr , (Addressed to Sir J D Grififfiths) Last year when I took basic electricity and magnetism course , my instructor discussed some interesting ideas which you discussed in your book ''Introduction to Electrodynamics'' ,one of that was calculating force exerted on a dielectric while it's...

Hi everyone Can anyone help me understanding the physical meaning for the complex dielectric constant? Assuming a electromagnetic wave from air to a conductor, the following equation is valid R= ((n-1)2+k2)/((n+1)2+k2) where K is the extinction coefficient (the complex part of the complex...

My partner and i have been running experiments for our research in micro algae separation, using a reactor containing aluminum electrodes. we run a 10v current across the electrodes, and flow saltwater between them. we were wondering how changing the conductivity of the saltwater might affect...

What happens when i apply dc current in them? And ac aswell? Im quite confused about them tbh. Edit: Dielectric*

Hi, My setup for measuring parallel plate capacitance consists of an LCR meter and a parallel plate test fixture. The area of the parallel plates is much larger than the area of the samples I am measuring. From what I've seen in literature, and my physics classes, the sample area should be...

In a linear isotropic homogeneous dielectric, P= χε0*E, where E is the net electric field from the effects of both free and bound charges. But E=(σfree—P)/ε0 So E itself depends on P. My concern is, isn't this circular? How can the polarization density depend on a field that itself depends...

Will the high surface area of carbon nanotubes and high dielectric constant of calcium copper titanate be used together in supercapacitors?

Homework Statement A capacitor, is fully charged by a battery. The battery is disconnected and a dielectric is inserted into the capacitor. Which of the following is true? I. Voltage will stay the same II. Potential energy of the capacitor will increase III. capacitance will increase...

Homework Statement My teacher told me that the force will increase ##k^2## times, where ##k## is the dielectric constant, but I don't see how. Homework EquationsThe Attempt at a Solution To start with, with no dielectric, the force between the plates is given by ##\frac{q^2}{2A\epsilon_{0}}##...

Dear all, I needed help in finding a source where the derivation of radiation emitted by a dielectric body is laid out. The derivation of spectral density of radiation emitted from a blackbody at a temperature ##T## is given in many books by populating the energy states using Bose-Einstein...

Why is dielectric material used for anti-reflective coating? / Why not use a material this is NOT a dielectric material? Is it because dielectric materials are highly transparent?

Homework Statement Sorry for the dull question. Problem is as shown/attached Homework Equations The waves in part ii) are traveling in a HIL dielectric of permittivity ##\epsilon_{r}## from ##0 <z<d## and then hit an ideal metal boundary at ##z=d##. The Attempt at a Solution I figure this...

Homework Statement A parallel plate capacitor having plates of area S and plate separation d, has capacitance C1 in air. When two dielectrics of different relative permittivities ( ε1=2 and ε2=4) are introduced between the two plates as shown in the figure, the capacitance becomes C2. the ratio...

Cant seem to find a kv/mm for waterglass/sodium silicate. I was thinking of using it as an electrical insulator for vacuum feedthroughs, expecting an easy seal as I hear it expands when heat cured, therefore pushing against the chamber wall and the wires to prevent leaks and also seal by its...

Homework Statement A ##12 \mu F## capacitor ##C_{1}## consists of plates ##A## and ##B##. An ##18 \mu F## capacitor ##C_{2}## consists of plates ##C## and ##D##. (a) Each are charged up by a ##10 V## battery such that plates ##A## and ##C## are positively charged. They are disconnected from...

Homework Statement The plates of a parallel plate capacitor of capacitance C0 are horizontal. Into the gap a slab of dielectric material with K=2 is placed, filling the bottom half of the gap between the plates. What is the resulting new capacitance? Homework Equations C = Q/V = κɛ0A/d The...

Hello everyone, Where can i get dielectric loss values of very thin SiO2 layers (nm) at high frequency range (GHz).? i.e SiO2 oxide layer dielectric loss of MOS (metal-oxide-semiconductor). I searched a lot on net but i didn't find any useful result, any reference is greatly appreciated.

Hi guys, I've been trying to figure out how the capacitance of two microstrips, separated a distance d, are influenced by the presence of a dielectric. The dielectric will be a height (h) above the strips and has restricted movement. Using the electric potential I am able to derive a function...

Homework Statement A capacitor with two parallel plates of area 88.5 cm2 and nylon (dielectric strength 14 MV/m) inserted between them breaks down when a potential difference of 5.80 kV is applied. What is the maximum charge the plates will hold when the nylon is removed and the space filled...

Homework Statement Consider the situation shown in the figure. The width of each plate is b. the capacitor plates are rigidly clamped in the lab and connected to a battery of emf E. All surfaces are frictionless. Calculate the value of M for which the dielectric will stay in equilibrium...

Homework Statement A parallel plate capacitor has a capacitance of 1.5µF with air between the plates. The capacitor is connected a 12V battery and charged. The battery is then removed. When a dielectric is placed between the plates, a potential difference of 5.0V is measured across the plates...

Homework Statement You want to maintain a potential difference of 5000 V between the plates of a parallel-plate capacitor. What is the minimum value of the plate separation if the space between the plates is completely filled by a slab of mica? Homework Equations V=Ed (parallel plate...

My textbook says this makes three pairs of parallel capacitors. I don't understand how?To make three pairs of parallel plates capacitors we at least need four plates but here we have only two

Hello. I've been doing some personal learning on the topic of dielectrics and I've come across a bit of a problem. Say I charged up a cap. plate with a battery and then I disconnected in the battery. Then I inserted some dielectric material in the middle. It is then given that E1 = E2 * k...

Homework Statement A plane electromagnetic wave of frequency 5×1014 Hz and amplitude 103 V/m, traveling in a homogeneous dielectric medium of dielectric constant 1.69, is incident normally at the interface with a second dielectric medium of dielectric constant 2.25. The ratio of the amplitude...

I have a capacitor which I would like to know if the dielectric has undergone dielectric breakdown. Is there anyway I can tell without specialist equipment, is there physical damage to the material that I can see with the naked eye? The material is quartz. Thanks.

First, sorry if something is not totally clear, I'm translating physics term the best I can! 1. Homework Statement A sphere or radius a of permittivity ε2 is placed in a dielectric ε1. Without the sphere, we would have E = E0. We want to find the solution to this problem when ε2 = 1...

Does anyone have a formula and derivation of the force between two charges in the presence of two dielectric media. Specifically, have the two dielectric media separated by a plane at z = 0. I have a developed a solution using image charges to matched the boundary conditions at the dielectric...

Consider this stack of materials: metal - dielectric - air - dielectric - metal Assume that air has a lower breakdown field than the dielectric. As the voltage (DC) on the metal electrodes increases the field inside the air gap increases and eventually reaches breakdown causing it to become...

Hi, I've been working on a problem for some time now and I can't figure out why exactly this happens, and I've been looking for some insight. The phenomenon can be seen in this video. We can see that the oil rearranges itself due to a high-voltage electric field. Thinking about this, my...

http://local.eleceng.uct.ac.za/courses/EEE3055F/lecture_notes/2011_old/eee3055f_Ch4_2up.pdf (Page 4.4 )I am having a trouble with understanding why closed loop line integration is 0 at dielectric boundary. As far as I know, closed loop line integration is 0 because electric field is...

I want to know the relationship between the optical axis direction of a crystal and the dielectric constants in different directions in an anisotropic material.

A typical mode in a dielectric slab like this, with propagation along x, uniformity along z and refractive index variation along y, is represented by the following function: f (y) = \begin{cases} \displaystyle \frac{\cos (k_1 y)}{\cos (k_1 d)} && |y| \leq d \\ e^{-j k_2 (y - d)} && |y| \geq d...

Homework Statement Calculate the capacitance of the parallel plate capacitor shown in the following figure,between points X and Y. Homework Equations ##C##=##\frac{Kε0A}{d}## The Attempt at a Solution Which capacitor has an area "A"? I will have to transform this into circuit diagram.

A dielectric is placed between two capacitors ,How (a) gets transformed into (b) Where did all the dipoles present in picture (a)go?And from where the negative and positive charges appeared inside the dielectric in picture (b)

Homework Statement A parallel plate capacitor was lowered into water in a horizontal position, with water filling up the gap between the plates (gap d=1.0mm). Then, a constant voltage V=200volt is applied to the capacitor. Find the increment of pressure in the water between the gap. Homework...

Homework Statement Show the the induced charge density on a dielectric placed inside a capacitor is given by $$\frac{k-1}{k}\sigma$$ where ##\sigma## is the charge density of the capacitor plates and ##k## is the dielectric constant. Homework Equations $$E=\frac{E_0}{k}$$ The Attempt at a...

Can a rotating dielectric disc be polarized? No external electric or magnetic field .

I saw an experiment the other day, where a van de graaf generator charges up this big smooth chrome sphere. There is a "wand" with a much smaller sphere nearby that's grounded, and periodically a spark can be heard and seen when the big sphere dischrages to the wand, which corresponds to...

Why do capacitors need dielectrics (insulators) in between the two plates(conductors)?What if there is no dielectric in capacitors ?Function of a capacitor is " a capacitor stores energy in the form of an electrostatic field between its plates" Let's say there is a conductor is between them...

Homework Statement Homework EquationsThe Attempt at a Solution for #14, I remember a battery maintains the potential therefore, V should be constant; dielectric increases charge on plates and increases capacitance but I couldn't find an option that matched. The answer key says "d" but I...

Homework Statement Determine the conductivity of the insulator in a spherical capacitor filled with weakly conductive dielectric. Specific conductivity of the dielectric is λ, the dielectric permittivity ε. Ansver in book is ##\Lambda = \frac{4\pi\lambda}{\epsilon} \frac{R_1R_2}{R_1-R_2}##...

Homework Statement 2 concentric conducting spherical shells, with radii a and 2a, have charge +Q and -Q respectively. The space between the shells is filled with a linear dielectric with permittivity ε(r) = (ε0*a)/(1.5*a - 0.5*r), which varies with distance r. a) Use Gauss's law to determine...

Problem: When a dielectric slab is inserted between the plates of one of the two identical capacitors in Fig. 25-23, do the following properties of that capacitor increase, decrease, or remain the same: (a) capacitance, (b) charge, (c) potential difference (d) How about the same properties of...