Conductor Definition and 790 Threads

I want to apply a net electrostatic charge with controlled constant voltage (polarity switchable as well) to a conductor. The conductor will continually be charged by friction, so I want to have a circuit apparatus operating on it to continually re-supply or drain charge as needed. Does such a...

Homework Statement See attached image. Homework Equations Potential difference over a line: V=\int E dl The Attempt at a Solution I assume that the approach to take would be to divide up the problem into different parts, and simply add them together. \int E dl I am a bit...

Homework Statement An initially neutral conductor contains a hollow cavity in which there is a +100nC point charge. A charged rod transfers -50nC to the conductor. Afterward, what is the charge (a) on the inner wall of the cavity wall, and (b) on the exterior surface of the conductor...

I'm not entirely sure if this is meant to be in the "advanced physics" section, it's for my undergraduate degree anyway. Homework Statement A conducting sphere of radius R, carries a total charge of q. It is surrounded by an electrically neutral conducting shell with an inner radius, a, and...

in the case of a spherical conductor the charges reside on the surface...the electric field is perpendicular to this surface (radial) and no parallel component exists ,as it leads to the flow of charges across the surface...why is this flow not feasible i.e why does the parallel component...

Homework Statement 1) A charge Q is placed in a uniform magnetic field of magnitude a that proceeds in the -z direction. Its displacement is given by r(t) = (at^2+bt, 2bt, a). a) Find v(t). c) Find the magnetic force exerted on the charge at time t=t'. d) Now the magnetic field at time t'...

A solid spherical conductor of radius 1.50 m has a small spherical cavity of radius 0.50 m with the same center. The net charge of the conductor is zero. An object with a net charge of 4.00 nC is placed inside the cavity in such a way that it is isolated from the conductor. I know the answers I...

Hello I have just read first five chapters from Feynman's "Lectures on Physics Vol. 2" on electromagnetism and couldn't find satisfactory answer to my question, so I am posting this question. Its claimed that electric field inside a "perfect conductor" (something with unlimited...

Homework Statement My book draws this picture where there is an external field outside a conductor and inside has charges where an opposite field takes place inside and there a net zero field occurs. But the book then generalizes that ALL conductors have zero field inside. My question...

im asking this because, if one has a conductor and there is a extern electric field then all the charge in the conductor redistributes itself so as to cancel out the external field. but let's suppose that there is not enough charge in the conductor to cancel out the electric field, would this...

I want to verify my understanding about skin effect and plane wave of conductor wire. In the diagram, assume long straight on z axis. Wire with radius = a and conductance = \sigma . Accouding to the equation shown, the plane wave is going towards the center of the wire only...

Homework Statement What effects occur on a conductor within a circuit, for example copper wires - what can effect them and what can be done to control the effect? Homework Equations None The Attempt at a Solution I have no real understanding of electrics but one attempt is...

At equilibrium, a conducting object will have no electric field, current or excess charge in its interior. There's a fairly simple derivation for how an initial (non-equilibrium) interior charge density d0 falls to zero exponentially with time t when the conductor approaches equilibrium. For a...

I am following Engineering Electromagnetic by H. Hayt, And there, we derived, the speed of Electromagnetic wave in good copper is just around 3.2m/s. Sure, this can't mean it takes 1 second for a light bulb 3.2 m away to glow if I press a switch? I have experience that this is almost...

hi , i was just wondering, if the sea is a good conductor of electricity, when thunder should strike it, won't electricity be conducted everywhere and everything dies in the sea? how far does electricity spread out? is there some sort of limiting factor? thanks!

pardon me for asking such silly question. Why is it that the E-field in the interior of a conducting solid zero? even when the conducting solid have excess positive (or negative) charges? and this conducting solid is placed in an external E-field, will the E-field in the conducting solid...

Homework Statement "demonstrate that the capacitance of any conductor is always smaller than or equal to the capacitance of a conductor which can completely surround it" Homework Equations Multipole expansion? The Attempt at a Solution Tried to compare each terms of...

sorry i moved it to correct forum i rushed in, in my panic

This kind of confuses me. You have a capacitor which has a voltage of 200 volts. Now when doubling the distance between the plates and adding a 100 V voltage source to it, it is said that the voltage between the capacitor plates stays the same, as in 200 V. I don't follow. Someone care to...

[PLAIN]http://www.buildingtechnologies.siemens.com/bt/low-voltage/EN/news_installation-technology_installationstechnik/new_products/BETA/PublishingImages/5SL_Leitungsschutzschalter_Miniature-Circuit-Breakers.jpg Miniature circuit breaker (MCB) time-current characteristic has two specific...

Homework Statement An infinitely long wire contains a current I. A metal rod with length L moves with speed v. Determine the emf in the rod. http://img227.imageshack.us/img227/5149/52966616.jpg With \epsilon = -\frac{d\Phi_b}{dt}, I would have said emf = 0 at first. The current I generates...

Homework Statement Is it possible to create an electric field such that a neutral conductor will experience a net electric field inside?Homework Equations The Attempt at a Solution The definition of perfect conductor is that there are an infinite amount of charges free to move so that electric...

I presume so because the charges will reside on the surface of the hollow conductor and the conductor itself will stop any electric field lines from those charges penetrating into the interior of the conducting shell. If there is no field getting inside then the potential inside is zero...

If the charge on an isolated conductor is negative, is it's capacitance negative by the formula C = Q / V??

Can Ampère's circuital law be used to find electric field for a finite (say length l) current carrying this conductor at a finite point away from it? If yes, then what will be Magnetic field due to a wire extending from (0,-a/2) to (0,a/2) carrying current “I” at a point (b,0) from it, if I...

Potential of Concentric Spherical Insulator and Conductor...Please Help Homework Statement A solid insulating sphere of radius a = 4.9 cm is fixed at the origin of a co-ordinate system as shown. The sphere is uniformly charged with a charge density ρ = -108 μC/m3. Concentric with the sphere...

Hello, I have an electric cable in a vertical steel Tube. I estimated the temperature that will reach the JTube exposed to sun radiation. I came with these equations QCable+ Qsun - Qradiated = mc( Tfinal - TAmbient) where QRadiated= k.A.(Tfinal^4-TAmbient^4), QSun=234 [W/m^2] * A...

I am having trouble understanding this. For example, say I have this: [positive point charge] [A][neutral conducting sphere][B] [...infinity] I know the point charge will create a field radially outward. But now I'm thinking of a test charge being brought in...

Homework Statement I know the definition of electric potential is the work done to bring a test charge from infinity to a particular point. But I read about some question asking the electric potential of a charged conductor, I wonder what that means, whether it is the potential of the surface...

In the treatment of waveguides, it's assumed that in a perfect conductor, both electric magnetic fields vanish. The first part is easy to understand because a non-zero electric field will cause the electrons to move. However why does the magnetic field also vanish?

I've read that as of now the highest Tc is 254 K ((Tl4Ba)Ba2Ca2Cu7O13+). Is that correct? My source is superconductors.org, can that site be trusted? It seems like the record has been rapidly increasing in the past decade. If there are any experts out there, do you think we will reach a Tc of...

Code Requirements for "finger-safe" Conductor Rail I'm planning to install conductor rails about 7ft above the floor in an astronomical observatory. The rails are IP2 "finger safe" rated. Where should I look to determine if this is sufficient enough for conductor rails which will be within...

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...

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...