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Questions tagged [insulators]

Electrical insulators are materials through which electric charge does not flow freely. Insulators have high electrical resistivity.

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Location of free charge in insulators

I'm going through the introductory section to Electrostatics in Materials in Griffiths, and I have a question that I can't seem to find a satisfactory answer to. If I have an insulator with free ...
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Why electron can go through PVC insulator

I connected a PVC insulated alligator clip test lead to a 12V (give 20V) DC power supply positive terminal and a multimeter. After that I connected an other one to the multimeter ground, and a third ...
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Is it absolutely insulating in its interior of topological insulator?

If putting a 3D topological insulator (TI) into a sandwich testing structure (electrode-TI-electrode), can we detect any leakage current in its interior like the ordinary insulator? Is it absolutely ...
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What are the Possible Dangers of an Overheating Household Wire? [closed]

Can anyone tell me any possible dangers/risks that could happen if a wire overheats even if it's insulated properly?
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29 views

New black Van in South Florida - To insulate or Not? Radiative Cooling effect?

I'm not homeless, I'm just frugal and trying to drive a lot less.. maybe I'm adventurous. :) Anyways, I've been working , eating and sleeping out of my new Black van. The van is brutally hot during ...
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Electrical vs Heating Insulation

Let's say we have a 120V cable and a 600V cable, this means that the 600V needs more electrical insulation to prevent the insulator from exceeding its dielectric strength. But in the other case, the ...
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150 views

Why High Voltage Power Lines need more Insulation than a low one?

"A 400 kV cable requires less insulation than a 240V cable." This was regarded as False in one of my question papers, but why? Doesn't a higher voltage means, lower current(P=V. I) and a lower ...
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Semiconductors/insulators: Why is the fermi energy between the valence and conduction band?

Ive asking myself a question on the fermi-energy. The fermi-energy is defined as the maximum energy which an electron, following the Pauli-rule, can have at T=0. In semiconductors and insulators the ...
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Two neutral metal objects are connected by a wooden bar when a positively charged object contacts one of the metal objects

Two neutral metal objects are connected by a wooden bar when a positively charged object contacts one of the metal objects. What should we expect the charge to be on both the other metal object and ...
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Why don't insulators conduct electricity? [closed]

I have been taught in school that because of the high energy band gap (approx. $9~\text{eV}$ or more) of an insulator, electrons can't jump to the conduction band. But also $1~\text{eV} = 1.6 \cdot ...
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56 views

Could one make an electrostatic “permanent magnet”?

Could one make a negatively-charged insulator with the extra electrons trapped all the way through its volume by building it up layer by layer with electrons "sprayed" onto each layer as it was ...
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54 views

Is diamond able to conduct electricity given 5.5 eV of energy? How do we then identify insulators and semiconductors?

I have learnt that the band gap for diamond, an insulator, is $5.5\:\rm eV$. Does this mean that diamond is able to conduct electricity if we give it this immense amount of energy (let's assume we do ...
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253 views

Electric fields and insulators

Will the electric field of an induced dipole in an insulator match the electric field inducing it but in the opposite direction? I have 2 counter theories: Let's say I place an insulator (and let's ...
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Effect of humidity on removing excess charge from objects [duplicate]

The usual answer to the question "why electrostatic discharge happens more often on dry days" is that water - due to its polarity - has the tendency to remove the excess charge. But I do not ...
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1answer
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Ways to generate long-lasting charge on materials surface?

First off, I am no physicist, please don't judge me if I said something wrong. I read that insulator surface can carry a static charge by rubbing against another insulator with a different electron ...
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1answer
42 views

Material with fairly high resistivity, but allows flow of charge

Is there a material with fairly high resistivity (at least semi-conductor level), but also allows the flow of charge through it (and subsequently to the ground)? The flow of charge does not need to be ...
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156 views

If vacuum is an insulator, then why do charges flow inside a vacuum tube?

Since vacuum or free space is used as insulators in capacitors, how is it possible for charges to flow inside a vacuum tube?
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Are materials which are bad at conducting heat always bad at conducting electricity also?

When defining a material's conductivity, we usually consider its conductivity of heat and conductivity of electricity separately. However, I realize that materials like metal conduct both heat and ...
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71 views

Insulator behavior of large U limit in Hubbard model

I am now learning the many-body physics and having some questions about the insulator behavior of large $U$ limit for the Hubbard model : \begin{equation} H = -t\sum_{\left\langle {i,j} \right\rangle,...
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269 views

Calculating temperature of insulated container over time

Experiment In Science Olympiad there is this competition called Thermodynamics. In thermodynamics, we have to make an insulating box that is smaller than 15cm by 15cm by 15cm. This box will have a ...
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1answer
2k views

Does the shiny side of foil keep food warm? [duplicate]

As the title asks, does the shiny side of foil really insulate or keep food warm when facing inwards? I've heard that the shiny reflective surface of the foil reflects the infrared energy. Is this ...
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1answer
132 views

Is electron-hole pair generation and recombination process in insulator same as semiconductors?

I was trying to understand the electron-hole generation and recombination process in materials. However, most of the sources explain the phenomenon by using semiconductors through the energy-band ...
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1answer
538 views

How do insulators lose their charge?

Some theoretical questions that got me confused during physics lecture today. bringing a conducting balloon to a negatively charged rod close will allow the conducting balloon have positive charges ...
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1answer
114 views

Why we assume a negative charge inside a cavity of non-conductors?

The electric field of a spherical non-conductor, with uniform charge density $\rho$ is, $$E_s(r)=\frac{\rho r}{3\epsilon_0}$$ It is mentioned in a lot of places that the electric field inside the ...
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268 views

Why don't insulators attract even if charged?

I understand that/ obviously, opposite charges will attract? However, I am still slightly confused about what happens if an insulator becomes charged. How come an insulator, which is charged, will ...
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What is the basic difference between insulator and dielectric? [closed]

I just want to know the similarities and dissimilarities between them.
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Why aren't all insulators transparent, since they have a large band gap?

According to Floris' answer in this link, diamonds are transparent as they have large band gaps while graphite is black as it is a conductor. As electrical insulators generally have a large band gap, ...
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214 views

Is wearing an insulated metal armor against a lightning safe?

Related: Is wearing metal armor during lightning safe? only partially answer my question. During a discussion in my question in Worldbuilding, this answer explain that as long as the metal armor is ...
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1answer
5k views

What happens to any insulator when it is placed in any external electric field?

This is in the case of a conductor: I want to know what happens in the case of insulators.
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How do excess charges move in an insulator?

I am currently studying intro into electrostatics and reading my notes from teacher that stated, "an insulator holds on tightly to its outer electrons and does not permit the flow of electric charges ...
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44 views

Superconductor-insulator transition at finite temperatures

I know that it is possible to have a phase transition at $T=0$ between a superconductor and an insulator. The mechanism is not the "usual" QPT as the system is not translationally invariant: the ...
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1answer
98 views

Will a charge ballon get attracted to a conductor or insulator?

Will a inflated ballon charged by rubbing with fur get attracted to a conductor or an insulator ?
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117 views

Are there general Soliton-Instanton correspondence?

In the symmetric double well potential, the solutions in $1+1$ static and real $\varphi^4$ theory, are solitons. However, we know that such theories are "dual" to one dimensional real $\varphi^4$ ...
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1answer
2k views

Why does a plastic comb attracts tiny bits of paper if it is an insulator? [duplicate]

When we rub plastic comb against dry hair, it attracts tiny bits of paper. We know that plastic comb is an insulator of electricity but then how is it getting charged and showing the property of ...
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236 views

Can insulators send charges to other objects?

Basically, a plastic rod (an insulator) won't be able to receive charges from a charged conductor, but if I charge this rod by friction and then make it touch my hand, will my hand get charged? If so ...
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69 views

insulated charged object making contact with an open circuit

I have a circuit in where an "object" is going to be placed instantaneously in the gap of the circuit, but the object will not touch the wire on either side of the gap. The objects has two blocks of ...
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2answers
480 views

Why is it possible to pass current to another insulated human while touching a plasma tube?

I work in a museum and we have a large plasma tube (I do not know any details of the current used within the tube). When I place my hand on the tube and then hold out my finger and touch another human ...
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1answer
809 views

Charging by friction

Why does charging by friction charges an insulating material even if an insulator does not allow flow of electrons between an object to another? Is it because of the TriboElectric effect but doesn't ...
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74 views

Why can a rubber sole undergo electrostatic discharge?

I understand that rubber soles can get gain (or get rid) of electrons when a person walks.How can electrons go from the soles to the fingers when that person touches an electric circuit connected to ...
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1answer
222 views

Interaction of charged particles with a conducting or insulating surface

If I have a charged particle floating in a vacuum, and it strikes a conductor or insulator on its way, what would happen? Would the electron be taken into the conductor? or would it just bounce off ...
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2answers
1k views

What is the 'Drude Weight' and why is it important?

I have been trying to understand the Drude Weight quantity that is used in the Metal-Insulator transition and Spin chain literature, and I have not been able to find any clear intuitive explanations ...
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751 views

Charged body in hollow conductor : what is the role of insulators and how does the charge distribution change if insulators vs conductors are used?

Question as written in textbook: "Figure 1 illustrates a nested arrangement of four cylindrical conductors (seen side-on in cross-section) in which the cylinders are separated by electrical insulators....
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1k views

Why can an insulator send charges to a conductor via conduction, and not upon an insulator via conduction?

Suppose we have an ebonite rod (insulator). This rod has a negative charge, and once it touches a neutral pith ball, charges are distributed amongst the pith ball. However, why doesn't the same happen ...
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173 views

Electrical Physics: Rank the charge densities in the blocks

Im just beginning to learn about electrical physics. Im a bit confused with ranking the charge density. I think Im suppose to compare the ratios of the blocks. Would block E have the Greatest charge ...
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1answer
429 views

Is an EMF more/same/less in an insulator than in a conductor?

Is an EMF (electromotive force) more/same/less in an insulator than in a conductor? For example: A loop of copper and a loop of plastic in a changing magnetic field. In which will the emf be the ...
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3k views

What is the difference of the gap between superconductor and insulator?

This is what I learned from textbook. An insulator is insulate as the gap between the valence band and the conduction band and the fermi level lies in the gap. A superconductor is super electronically ...
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3answers
4k views

What is it about the “conduction band” of a material that is distinct from the valence band?

I'm taking a course in nanotech and we're discussing nanoelectronics. This has led to a discussion of conductors, semiconductors, and insulators. I have a number of lovely diagrams explaining the fact ...
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3answers
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Why are ceramics good electric insulators?

I know it depends a lot on the composition, so not all are great electric insulators. So what makes it good or bad? And is it different from what makes them good thermal insulators? Power line ...
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4k views

what is the physical significance of dielectric constant and loss tangent?

I want to know that the significance of dielectric constant and loss tangent behaviour. How it characterises the materials. and possible relation between the dielectric constant and polarisation ?
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How can a metal and an insulator both have high dielectric constants, yet one is conducting while the other is insulating?

I don't get it: insulators are used as dielectrics. The higher the dielectric constant, the better the insulator is. However, the dielectric constant of metals is considered to be infinite. Doesn'...