What is Conductor: Definition and 811 Discussions

In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge (electrical current) in one or more directions. Materials made of metal are common electrical conductors. Electrical current is generated by the flow of negatively charged electrons, positively charged holes, and positive or negative ions in some cases.
In order for current to flow within a closed electrical circuit, it is not necessary for one charged particle to travel from the component producing the current (the current source) to those consuming it (the loads). Instead, the charged particle simply needs to nudge its neighbor a finite amount, who will nudge its neighbor, and on and on until a particle is nudged into the consumer, thus powering it. Essentially what is occurring is a long chain of momentum transfer between mobile charge carriers; the Drude model of conduction describes this process more rigorously. This momentum transfer model makes metal an ideal choice for a conductor; metals, characteristically, possess a delocalized sea of electrons which gives the electrons enough mobility to collide and thus affect a momentum transfer.
As discussed above, electrons are the primary mover in metals; however, other devices such as the cationic electrolyte(s) of a battery, or the mobile protons of the proton conductor of a fuel cell rely on positive charge carriers. Insulators are non-conducting materials with few mobile charges that support only insignificant electric currents.

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  1. P

    As temperature of a conductor increases why does the ratio of

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

    Why do magnetic fields decay exponentially with depth in a conductor?

    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...
  3. M

    Field inside a conductor is zero

    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...
  4. B

    What happens to an electron created inside a conductor in an electric field?

    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...
  5. U

    Magnitude of induced voltage in conductor within AC solenoid

    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...
  6. PainterGuy

    Ohmic conductor, when R tends to zero I=V/R

    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...
  7. U

    Applying an electrostatic charge to a conductor

    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...
  8. L

    Potential difference of 2 points across charge and conductor

    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...
  9. JimiJams

    How Does Charge Redistribution Work in a Conductor with a Cavity?

    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...
  10. S

    Electric field in a conductor with an internal cavity

    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...
  11. A

    Flow of charges in a conductor

    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...
  12. A

    Finding magnetic field from magnetic force / semielliptical conductor

    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'...
  13. T

    Solving Spherical Conductor: Net Charge and Electric Field

    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...
  14. I

    Microscopic electric fields in a conductor

    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...
  15. F

    How can a conductor have zero field inside when it is not in equilbrium

    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...
  16. B

    Complicated conductor geometry decomposed with superposition

    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...
  17. U

    How much charge is there on an conductor

    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...
  18. Y

    Confused about plane wave and skin effect in conductor wire.

    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...
  19. M

    What effects does a conductor have on a circuit. How can they be minimised?

    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...
  20. S

    Question about electrostatic equilibrium for a conductor

    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...
  21. I_am_learning

    Electromagnetic Waves speed in Conductor

    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...
  22. Q

    Sea is a good conductor of electricity

    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!
  23. Y

    Understanding Conducting Solids: Exploring the E-field Phenomenon

    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...
  24. M

    Conductor that can completely surround another conductor?

    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...
  25. P

    What is the value of the band gap in a good conductor

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

    Connecting a conductor with a voltage source

    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...
  27. V

    MCB characteristics and specification of conductor cross-section

    [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...
  28. S

    EM: induction in a moving conductor

    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...
  29. P

    Electric field inside a conductor not zero

    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...
  30. J

    Is the potential inside a charged hollow conductor zero?

    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...
  31. A

    If the charge on an isolated conductor is negative, is it's

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

    Ampère's circuital law and finite conductor

    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...
  33. S

    Potential of Concentric Spherical Insulator and Conductor --

    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...
  34. S

    Electric cable in a Vertical Tube: Estimate the Conductor Temperature

    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...
  35. N

    How Does Electrostatic Induction Affect Electric Fields Near Conductors?

    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...
  36. N

    Why is the surface of a conductor equipotential?

    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...
  37. Terocamo

    Electric potential of a conductor.

    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...
  38. P

    Why is there no magnetic field in a perfect conductor

    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?
  39. S

    What is the current highest temperature super conductor?

    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...
  40. J

    Code Requirements for finger-safe Conductor Rail

    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...
  41. F

    Prove That Charge Distributes Uniformly on a Disk Conductor

    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?
  42. G

    Calculating Alternating Voltage of Conductor in Magnetic Field

    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...
  43. C

    Litz conductor surrounded by drain wires = huge capacitance?

    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...
  44. G

    Charge displacement through a conductor

    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...
  45. C

    Conductor Bundles: Reduce Impedance Per Meter

    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...
  46. V

    Non uniform charge distribution on conductor surface

    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.
  47. J

    Magnetic field induced by current in a conductor question

    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...
  48. P

    Magnetic field in perfect conductor

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

    Resistance of Cylindrical Conductor

    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...
  50. A

    A Conductor within a Capacitor

    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...
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