Conductor Definition and 821 Threads

This is just a hypothetical questions, but... Would it be possible to have a capacitor so large that its able to store all the free electrons in the wire in the circuit its attached to? Then, this would mean all the free electrons have been removed from the wire, thus making the wire non...

Hi there, My boyfriend and I have been bashing our head against this past exam question for some time now, any physical insight would be appreciated. Homework Statement A long straight conductor has a circular cross-section of radius R and carries a current I. Through the conductor...

Homework Statement Find the induced emf in a rotating disc of radius (a) in a magnetic field (B), rotating with uniform angular velocity (w). If the disc is replaced by a rotating conductor of length (a) fixed at one end find the induced emf in the conductor. 2. The attempt at a solution...

Homework Statement How does the electric current flow through this circuit? 2. The attempt at a solution It would make sense for me to take the path where there's no resistance and skip the path with the resistance R1, but I'm not 100% sure about that. So how does it flow? pic1 or pic2...

What happens if I place a solid conductor in a static B field. I mean B fields can't do work so it won't induce a current unless its a superconductor. Will it shift the electron orbitals because of the Lorentz force? Any input will be much appreciated.

Hey all! I've return back to my year 12 assignment, the railgun. I got a working model back then, but unfortunately didn't write up a good report. I have the videos on youtube if anyone is interested. The reason for the conductive liquids is because I want to tackle the arcing issue. I...

Hi all, I need some help understanding why exactly there is no electric field inside any conductor (charged or uncharged). I am in year 12, and I would like to understand the reasoning behind it in terms of the MOTION OF CHARGES in the conductor. What I know so far: - Charges (electrons)...

Homework Statement A hollow sherical conducting shell is suspended in air by an insulated string. The total charge on the conductor is -6 microCoulombs. If an additional point charge of +2 microCoulombs is placed in the hollow region inside the shell what is the total charge induced on the...

I have written this problem myself to present to my professor. He teaches HVAC and Electrical for the department of Construction Management. Some of the problems and solutions we do in class are inconsistent with the material I was taught in physics. He really appreciates my criticism and I...

Homework Statement The problem asks us to find the magnetic field inside a coaxial conductor that consists of an aluminum wire of radius r1 surrounded by a cylindrical aluminum shell of inner radius r2 and outer radius r3. I know how to do this, but it also says that there is oil flowing...

as temperature of a conductor increases why does the ratio of conductivity to resistivity increase ?

Homework Statement I am a HS student researching the penetration depths of magnetic fields in conductors. Specifially, I am investigating the exponential decay of eddy currents induced within a conductor in the presence of a rapidly changing magnetic field. I am a bit confused as to why the...

Homework Statement I know that the field inside a conductor is zero but what if there was a charged object in the cylinder I mean in some examples I see infinite charged wire inside an infinite hollow conduction cylinder with radius a but if we take a cylindrical gaussian surface with r <a...

Heres's the situation: A neutron enters a block of Gadolinium, it gets absorbed at some point and emits an electron via internal conversion. This electron has an energy of 72 keV (most probable interaction). If the Gd block is in an electric field, what describes the motion of the electron...

Please note, I'm not in school anymore -- just a basic physics question! Homework Statement A conductor is placed inside the coil of an induction heater. Imagine that the inductor coil has radius R, number of turns N, operating frequency f [Hz], drawing current I = I0 * sin(2*pi*f*t). The...

hello fine people, ohm law is V=IR. suppose V is a constant value, as say 5. then it is I=5/R. when R is zero current is infinite. me thinks this is case with superconductors. me have been telled that limit of I=5/R does not exist. what did it mean in this real world problem? will this mean...

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...

Homework Statement A conductor has the shape of an infinite conducting plane except for a hemispherical boss (a raised part on the at surface) of radius a. A charge q is placed above the center of the boss at a distance p from the plane. Calculate the force on the charge. Homework...

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...

Okay, I have a feeling this is a pretty easy problem to solve, the only trouble is, my professor worded it really weirdly, so I only have half an idea of what it's asking. Any ideas? ----------- Let the Electric field be E at a point P near a conductiong material. Because of electrostatic...

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...