Insulator Definition and 130 Threads

Homework Statement A long cylindrical insulator has a uniform charge density of 1.79 µC/m and a radius of 3 cm. What is the electric field inside the insultor at a distance of (a) 2 cm? [Answer in units of N/C] (b) 10 cm. Homework Equations ∫ E • dA = Q_enclosed / e_0The Attempt at a Solution...

I feel so ashamed to ask a question this simple, but how does an insulator get charged? Let's say rubbing a glass rod with cat's fur. I thought that insulator means there is no free electron. Does rubbing means turning the neutral atoms at the surface of the glass rod into ions? or...

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?

i do not really understand wigmer-mermin theorem in my impression, it states that there is no continuous symmetry breaking in 1d and 2d so does wigner-mermin theorem rules out SF-Mott insulator transtion in 1d and 2d lattices ?

Homework Statement Homework Equations EA = Qenclosed / epsilon The Attempt at a Solution I found the electric field outside to be \rho*d/2\epsilon_{0}. Not sure if that helps, I don't know what to do since it says "as a function of x"

Hi, I always thought vacuum is the best insulator, until I find figures that state breakdown field for vacuum is about 2*10^6V/cm, while some dielectrics breakdown in field higher than that(Al2O3 is 4~5*10^6). So I'm wondering why? I mean electrons in vacuum has the highest potential energy...

[b]1. i have the answer, but just don't understnad it A small metal ball is given a negative charge, then brought near (i.e., within a few millimeters) to end A of the rod. What happens to end A of the rod when the ball approaches it closely this first time? Select the expected behavior...

Does anyone know of an experiment or know where I can find an experiment to compare the heat gain or heat loss by a conductor and an insulator?

For insulators the excess charge stays on the outside of the object. For conductors the excess charge travels through the sea of electrons until the net charge inside the object is zero with the rest of the charges pushed to the outer edges of the conductor. So with both the excess charges...

1. If an object is determined to have a negative charge of 160 NC, you can conclude that the object has an excess of a. 10^ 9 electrons b. 10^10 electrons c. 10^11 electrons d. 10^12 electrons e. 10^13 electrons I came up with c. 10^11 electrons by taking 160E-9C/1.6E-19C = 10^11. I...

Homework Statement Consider a thin ring of mass m that has a radius a and negligible width. The ring lies in a horizontal plan. The ring is an insulator and carries a fixed charge q that is uniformly distributed around its circumference. The ring is located in a magnetic field of strength B_0...

Homework Statement ok here's the problem: find the magnitude of the electric field inside uniformly charged insulating sphere of raduis R. Homework Equations application of gauss's law..but... The Attempt at a Solution should i use \phi = q_{encl}\epsilon_0 or \phi =...

Homework Statement I have a slab of conductor on the ground with thickness, a, and it extends in all directions infinitely. Then I have a slab of insulator above the conductor of thickness, a, and it also extends infinitely in all directions. The two slabs are a distance, 2a, from each...

Homework Statement An insulator in the shape of a spherical shell is shown. The insulator is defined by an inner radius a = 4 cm and an outer radius b = 6 cm and carries a total charge of Q = +9 microC. You may assume that the charge is distributed uniformly throughout the volume of the...

Good afternoon(or good morning,it depends on where you are :zzz:),this is my first topic in this great forum so don't be very tough with me okay? My question concerns the means of producing electricity and to be more precise:Electromagnetism. I read that if you move a conductor(such as copper...

Rod A is a positively charged insulator. Bob C and a second rod B are in contact with each other and made from conducting material. Rod B is fixed, and C is suspended from a wire and free to swing. Briefly describe what happens when A is brought near B. (I would draw a diagram but i can't figure...

We just got assigned to make an insulted cup for holding 200cc of boiling water It has to be able to hold 1 liter of water though Also, must be minimal size and mass There is a competition and whoever has the warmest water after 10 minutes, w/ smallest size and mass, gets the most points, wins...

by definition, a charge cannot move inside an insulator and by a similar definition, a charge can move inside a conductor. so, I don't understand how do we could charge an insulator, the charge cannot move, or there is something that i missed?

Homework Statement a circular ring made of an insulating material is cut in half. one half is given a charge -q uniformly distributed along its arc. The other half is given a charge +q also uniformly distributed along its arc. The two halves are then rejoined with insulation at the...

Somebody told me this and I have yet to figure out even if the statement is true or not.

Today I went to the JPL at Pasadena, and I saw the Aerogel. It is said it is the best insulator on Earth. They used it for insulating the Mars Rover vehicles. But it seems that is weak when shear stress is applied. Do you know what are the current applications of Aerogel, and why is it not...

Well i have to do this project/experiment creating an insulator that keeps water at the same temperature for an hour or some duration of time. I was thinking of Styrofoam, but i just wanted to post this here in case someone could help me out or give some ideas. I have to use recycled materials...

I'm working on the following problem: A small spherical insulator of mass 9.00 x 10-2 kg and charge q1 = +0.400 µC is hung by a thin wire of negligible mass. A charge q2 = -0.700 µC is held 0.150 m away from the sphere and directly to the right of it, so the wire makes an angle with the...

Hi, I have the following question: An uncharged wooden stick is balance on a pivot so that it can rotate freely. If a charged rod is brought close to one end of the stick, the stick will be... Attracted by the charged rod is the answer. This has got me confused for a while. Here is my...

Will I get a shock if I stand on an insulator and touched a iron which supplies a voltage of 2000000V and without Earth wire?

I have a question about insulator. The story starts from the fact that, taking a 1-D model, there are N possible values of wave vectors k within the first Brillouin zone [becasue number of possible k's = (2*Pi/a)/(2*Pi/L) = L/a = N where L is the length of the crystal, a is the distance...

Better insulator?? I am doing a project at school about heat insulation. I have one question, though. At school the walls are surrounded by concrete blocks. At home, however, my walls are surrounded by sheetrock. Which insulates heat better? Thank you

Consider a long uniformly charged, cylindrical insulator of radius R with charge density 1.1 micro-coulombs/m^3. (The volume of a cylinder with radius r and length l is V = pi*r^2*l) What is the magnitude of the electric field inside the insulator at a distance 2.7 cm from the axis (2.7 cm <...

Does anyone have any information about SOI. I've heard lots about it yet all i know of it, other than its benefits, is that instead of a metal on the oxide it uses a silicone. What is this silicone's structure, etc. Just some basic information about it would be great.

Im doing this coursework about what material can keep heat the longest. My test results show that Polystyrene was the best material, but why ? Why is polystyre a good insulator?