Conductor Definition and 821 Threads

I heard it's quite hard to prove that electric charge is distributed uniformly on a disk conductor. Can you point me to some resources online on the subject?

Hey, I asked myself, how can I use: U=\oint (v\times B) ds (1) to calculate for example the alternating voltage of a conductor loop turning in a constant magnetic field. But I am not only interested in this case, I just want to illustrate it. Therefore I thought about using Stokes theorem...

this type of cable is used to transfer power underground: http://www.mahanson.com/images/Hendrix%20Cable.jpg see the drain wires? i would think that those would be a huge problem because they are grounded and are right next to the conductor, i suppose any shielding would have this problem...

I read this in book that if we consider a conductor in which current I is flowing at a potential difference of V then in time ∆t charge equal to I ∆t will flow across the ends of conductor. But in time ∆t that much amount of charge will only be able to travel distance equal to drift velocity...

http://www.kabculus.com/capacitance-and-inductance-matrices/node7.html this short page describes conductor bundles, which are power transmission lines hung parallel to each other. i think the page is trying to explain why, when they are hung that way that they reduce impedance per meter, but i...

Hey everyone! I need some help. Can a non uniform charge distribution exist on a conductor's surface due to some external influence? Please explain bearing in mind that a conductor's surface is equipotential.

I am trying to understand Lenz law as it applies to an A.C. generator, Lenz law says " an induced current is always in such a direction as to oppose the motion or change causing it". Does this mean that if the north pole of a magnet passes a conductor in a stator, that the current induced in the...

Why in perfect conductor magnetic field B vanishes? It's often assumed while considering wave guides.

Homework Statement A circular disk of radius r and thickness d is made of material with resistivity p . Show that the resistance between points a and b (Fig. attached)is independent of r and is given by R=πp /2d Homework Equations R= p L / A where L and A are length and section...

Can anyone give me some hints as to how to proceed with the following problem. I have a capacitor where one capacitive plate is kept at a potential Va and the other at Vb (grounded). In between the two capacitive plates I insert a conductor which has some charge q on it. The conductor does...

I need clarifications on the following points regarding a capacitor in general. 1.When you bring another conductor near a charged conductor, the capacitance of the latter is said to increase, because the presence of the second conductor near the first one lowers the potential of the former...

When we connect a battery across a loop of wire having some finite resistance there comes into picture an electric field E which is empirically given by J/sigma.(sigma==>conductivity). but how can there exist an electric field inside a conductor??We had already learned that electric conductor...

Homework Statement A solid spherical conductor carries a charge Q. It is surrounded by a concentric uncharged spherical shell. The potential difference between the surface of solid sphere and the shell is V. If a charge of -3Q is given to the shell. Then the new potential difference between...

question For a plane wave of the form E(z,t)=Ee^i(kz-wt) and B(z,t)=Ee^(-kz)*e^i(kz-wt) write down the time-averaged ohmic heating loss per unit volume for any z. Homework Equations J=\sigmaE Maxwell's equations for linear media The Attempt at a Solution not sure where to start, i...

Why is the magnetic field outside a conductor zero?

I'm curious why electrons will travel near the perimeter of a large wire as opposed to using the whole cross section. I understand that electrons flowing through the wire repel each other and thus want to be as far apart as possible. Yes, but from this electrons should not just occupy the...

Homework Statement We are given that there is a hollow conducting sphere with a charge 1C (to simplify things) inside it and are asked to find the charge per unit area on the inner and outer surface of the sphere. Inner radius of the sphere is 1m and outer radius is 2m Homework Equations...

The Hall voltage across a 0.800-mm-thick conductor in a 1.30 T magnetic field is 3.2 uV when the current is 12.0 A. What is the charge carrier denisty in the conductor (in m-3). I was using the equation Vh=IB/ned where Vh is the Hall voltage I is the current B is the magnetic field...

Homework Statement Show that there is a force of 0.1N on a conductor of length 100mm carrying a current of 10A at right angles to a flux density of 0.1T. Show that 0.1J of work is done if the conductor is displaced by 100mm at right angles to its length. Homework Equations F=BIL...

In an infinitely long current carrying wire (assuming zero resistance) say there is a definite current. "Having current in it" means there is a flow of charge in it, which means if positive charge moves in one direction then negative charge moves in opposite direction. As we know that a charge...

Homework Statement v=qEt/m t=time between each collision q=charge on particle m=mass of particle E=electric field Why is this the average velocity/drift speed in a conductor? Homework Equations The Attempt at a Solution Doesn't qEt/m = the final velocity of the...

Homework Statement A Spherical conductor has an Electric field near its surface of 180 volts per inch. How much charge (in Coulombs) is on the sphere ? How many excess electrons are on the sphere? Will the air around the sphere break down and produce an arc ? Homework Equations Well, I...

Hi everybody... I have a simple question for you.. Where can i found the expression of the magnetic field around at the conductor which it has finite lenght? because i always found the megnetic filed in a conductor infinite length .. Sorry for the stupid question... tanks and best regard

Homework Statement The potential of a metal sphere of diameter 2 cm is 10^4 V relative to the ground. a) What is the surface charge density? b) How many electrons were removed from the sphere? c) What is the electric field strength at the surface? Homework Equations The Attempt...

Homework Statement a thin straight wire of length 0.4m is suspended from a spring balance. the scale reads 2g. the horizontal component of the Earth's magnetic field at that place is Bh=3*(10^-5)T. the wire is held horizontal and at right angles to Bh.if a current of 500A is passed through...

Homework Statement The problem is simple: there is a coaxial cable where the current flows in one direction in the inside conductor and in the opposite direction in the outside conductor. I'm asked to find the magnetic field on a point situated in the space between the two (that space is...

Homework Statement The figure shows a portion of an infinitely long, concentric cable in cross section. The inner conductor carries a charge of 5.1 nC/m and the outer conductor is uncharged. What is the electric field 1.9 cm from the central axis? The permittivity of free space is 8.85419e-12...

Hi, I am in Purcell's E&M book at the section explaining why the field is zero inside a hollow conductor of any shape. The proof given is that the potential function inside the conductor must obey Laplace's equation, and that the boundary of the region (in this case a rectangular metal box) is...

In a question there are two conducting shells of radii a and b (a<b),the outer shell is given a charge Q . And the inner shell is grounded then the potential of that shell was equated to zero and its charge was assumed q. And it resulted in an equation KQ/b + Kq/a = 0 this gave q = -(a/b)Q...

I beg you to understand my poor Eng.. If there is any poor grammar or spelling..please correct me.. While studying MHD with "An Introduction to Magnetohydrodynamics" written by Davidson, I encountered the term 'current density'.. As you know well, empirically, \mathbf{J} = \sigma...

Homework Statement A conductor is aligned with Earth's magnetic lines of force. The compass set above the conductor points in a line parallel to the conductor. A DC power supply is connected to form a closed circuit with the conductor. Explain how this information could be used to identify the...

Homework Statement Given an electrical dipole of electrical dipole momentum \vec P = p\hat k, centered in 0\hat i + 0\hat j + 0\hat k, find the potential in all the space, where V(\infty ) = 0. If the dipole is now surrounded by a hollow spherical conductor (initially discharged), find the...

The noise power in a conductor is given by P = k.t.B Does this mean the noise power is independant of the conductor length? Also, does this only apply for a conductor with no resistance? Thnks, Rudi

In the case of a finite conductor rod moving at a constant velocity perpendicularly to a uniform magnetic field, E. Purcell says that the free charges in the rod suffer a force such that they move to an extremity of the rod. When in the final state, he says (at least this is what I understand)...

When finding the angles for the finite length Biot-Savart formula of a filamentary conductor H = I*(cos(α2) - cos(α1))aΦ/(4πρ), is α1 supposed to be calculated at the start of the current, and α2 at the end? I'm just wondering because my book does it this way and vice-versa, so I'm not entirely...

Experience tells me it is, but my instinct tells me it shouldn't be. If you place 2 leads of a dc source into water, how does the charge get from one end to the other? I can see how it would work with salt water, with the disassociated ions carrying the charge, but that doesn't really have...

Homework Statement We know that free charges inside a conductor will eventually move to the conductor surface. Consider a free charge initially placed inside a conductor at t=0. Show that the free charge density \rho_f will dissolve exponentially with time. Express the characteristic time...

Homework Statement http://i258.photobucket.com/albums/hh258/Plutoniummatt/Untitled-1-2.jpg Homework Equations Pwr Ref Coeff: (Z'-Z)/(Z'+Z) all squared I maybe made a mistake but i can't spot it. And its bugging me I did square the whole thing afterward for the power...but...

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?

Hi. I'm doing an experiment and I'm kinda stuck. I know that a current produces a magnetic field. In this experiment there is a current carrying wire (copper) and a permanent magnet suspended above it. Deflection is being measured as the current is varied. I know that both magnetic...

Homework Statement An isolated conductor of thickness 'a' is placed between the plates of a parallel plate capacitor. Find the capacitance Homework Equations C = A/(4*pi*d) The Attempt at a Solution C1 = A/(4*pi*((d-a)/2)) C2 = A/(4*pi*((d-a)/2)) 1/C = 1/C1 + 1/C2...

There is this problem of a conducting rod being in a uniform magnetic field. When the rod is being moved, some answers that there will not be an induced emf as there is no change in magnetic flux linkage but some answer that there is. Anyone can clarify? Thanks.

I'm only midway to finish my introduction to electromagnetism (level around Resnick-Halliday) so I understand the concepts I will talk about, but I never derived them. For example, in the case of a spherical (not empty) conductor or any other solid conductor. If we charge it with extra...

Homework Statement First part of the question: A rectangular loop is placed near a long straight conductor. Conductor is oriented vertically to the XY plain at the origin the loop is contained within the YZ plain. Current passing through conductor. I = 19 Ampere dimensions of the loop...

Homework Statement Let's say I have : Spherical conductor of radius=x; Spherical conductor has a inner cubic cavity of side = b; inside the cubic cavity we have a charge = y; the surface of the sphere has a charge density = z; I need to calculate the electric field at some point g, where...

I was taught in my Eletricmagnetics Lessons that the density of electric charge is higher near the surface with big curvature and lower near the flat surface. Why does the density of electric charge has something to do with the surface curvature? Is this because such a system has the minimal...

A few questions about electric field here: 1. Why do charges have to be on the outer surface of the conductor? 2. Why no charge on the inner surface of a hollow conductor? 3. If charges cannot be inside the conductor, how come the electric potential is constant throughout the conductor when...

Homework Statement For the configuration shown in the figure below, suppose that a = 6.10 cm, b = 21.6 cm, and c = 26.6 cm. Furthermore, suppose that the electric field at a point 11.5 cm from the center is 3.37x10^3 N/C radially inward, while the electric field at a point 58.6 cm from the...

My teacher said so, but I just don't understand why. Is it because of the free movement of electrons inside the conductor?

Homework Statement An isolated capacitor with capacitance C = 1 µF has a charge Q = 22 µC on its plates. Now a conductor is inserted into the capacitor. The thickness of the conductor is 1/3 the thickness of the capacitor and is centered in between the plates of the capacitor. What is...