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. Godparicle

    What are the fields produced around a current carrying conductor?

    If we consider a current carrying conductor, every instant an electron enters the conductor, another electron will be leaving the conductor. Thus, the current carrying conductor will not be charged (i.e, it would not have any net positive or negative charge). Remember dipole has zero net charge...
  2. B

    Current flow through conductor immersed in water

    I have a small conductive, non-magnetic particle in which I will induce a fairly strong electromagnetic field into using a flow of current. I will then disconnect the power source that makes the particle electromagnetic. How long will it take the magnetic effect of the particle to diminish...
  3. G

    Is this the correct set up for the electric field?

    Homework Statement A spherical conductor of radius ##a## carries a charge q and also there is a jelly of constant charge ##rho## per unit volume extending from radius ##a## out to radius ##b##. I'm looking to see if I got the correct set up for the electric field of this spherical conductor for...
  4. A

    Conductor with shell problem getting zero as answer?

    1. Problem Statement: The figure shows a cross-section view of a very long cylindrical cable. There is an outer tube made of copper, inner radius 2R, outer radius 4R. The inner copper wire has radius R and is concentric with the tube. The inner wire has charge density –2λ (per unit length)...
  5. D

    Current capacity of a conductor?

    What determines the current capacity of a conductor? How can I know the maximum current, any conductor can carry safely, over shot or long durations of time. Example: A conductor that is 1m long, 0.00025m wide, and about 0.003m thick is used to deliver power continuously in a system. How much...
  6. T

    Ampere's Law and Conductor: Finding ∫B.dl for a Semicircle in the x-z Plane

    Homework Statement A conductor carrying current ‘I’ is in the form of a semicircle AB of radius ‘R’ and lying in the x-y plane with its centre at origin as shown in the figure. Find the magnitude of ∫B.dl for the circle 3x2 +3z2 =R2 in the x-z plane due to curve AB. Ans (1-√3/2)μ0I Homework...
  7. R

    Why the net field inside a conductor is zero?

    I do not really understand the big picture of gauss law. For what I know a conductor is a material where electrons can move freely, but I am reading my book and they show pictures where the protons are all right below the surface. My other question would be how can you describe the inside of a...
  8. A

    E-field vanishing *at* the surface of a conductor

    Suppose we apply a uniform field to an infinite conducting slab (i.e. like an infinite parallel plate capacitor, but the interior is included as part of the conductor). What is the resulting field? The simple answer is that a surface charge develops on the boundary planes of the conductor so as...
  9. ELB27

    Force of repulsion between two hemispheres of a metal conductor

    Homework Statement A metal sphere of radius ##R## carries a total charge ##Q##. What is the force of repulsion between the "northern" hemisphere and the "southern" hemisphere?Homework Equations The force per unit area on the surface of a conductor: \vec{f} = \frac{1}{2\epsilon_0}\sigma^2\hat{n}...
  10. R

    Can Plasma Conduct Electricity?

    My question is can plasma be used to conduct electricity as efficiently as a solid conductor? I know stability is an issue , but can it be overcome.
  11. M

    Effect of conductor orientation on transmission line ampacity

    Hi guys, I was playing around with conductor configurations and observed this phenomenon. Mind you these are for the High voltage transmission (138 kV) lines that span kms. So apparently, the orientation of the conductor relative to North will change the ampacity of the transmission line. Can...
  12. Greg Bernhardt

    Definition of Conductor: What is a Conductor?

    Definition/Summary A material is a conductor if it contains charges (eg electrons ions or "holes") which are free to move. In equilibrium, the charge inside a conductor is zero, and the density of charge at the surface is greater where the radius of curvature is less (and in the direction...
  13. Hardik Batra

    Maximizing Charge Repulsion: Understanding Earthing a Conductor 2

    1)If a negatively charge plastic rod (q=-20 e) is kept near the sphere.( which having net charge is zero.) Then how much negatively charge is repelled at the other end by this plastic rod on sphere. 2) if earthing is made to the sphere (at the other end), then all the charge which is repelled...
  14. leviterande

    Current carrying conductor has a net force parallel to earth, why?

    I am not sure if I should start a new thread or revive an old thread this because it is the same topic. Location of tests: Scandinavia I simply want to know why and how a current carrying conductor parallel to Earth surface moves perpendicularly to the current flow and parallel...
  15. T

    Conductor band overlap definition question

    i search all over the web but i cannot find the definition. Although I find all the literature saying that metal have valence band and conduction band overlapped, (and I cannot find a metal example with valence band and conduction band not being overlapped), I wonder if there is a...
  16. C

    Finding the velocity of a proton at the surface of a conductor

    Homework Statement A charged conducting sphere with radius 30cm is having a charge of -50nC. A proton is released from rest at R= 10m. Calculate the velocity of the proton when it reaches the surface of the conductor. What happens to the velocity of the proton when the charge on the sphere...
  17. Hardik Batra

    Earthing a Conductor: I Have Two Spheres

    I have two sphere. 1) one with free electron, if i connected sphere with the Earth by conducting wire all the free electron will flow to the earth. 2) one with positive charge, if i connected sphere with the Earth by conducting wire then the electron from the Earth will flow to the sphere...
  18. D

    External Electric Field of a Pulse Travelling in a Conductor

    If I send a pulse down a conducting wire, does the pulse emit an electric field?
  19. A

    Question about the movement of electrons in a conductor

    Hello, I know that the movement of a charged particle in space or a fluid caused by an electric field is accelerated(a = F / m) by the Coulomb force(Fc = k q1 q2 / d^2). And the Kinetic Energy of the particle is calculated through this equation ΔKE = q ΔV. But does an electron accelerate in a...
  20. baby_1

    So basic question about Charge density on the surface of the conductor

    Hello I want to know surface charge density of the conductor in all part of that is same or not? for example in this shape ? if isn't why and how the surface charge density spread? Thanks
  21. A

    How to derive the curl of E equation in the frame of the conductor?

    According to wikipedia, "The moving magnet and conductor problem", I stopped at the equation shown in the attachment. It said that the curl of the E` ( electric field in the frame of the conductor) is equal to minus of the dot product of the velocity of the conductor and the del multiplied by...
  22. I

    Electric Field in a Conductor

    I have read that in a charged conductor, all the charge is located at the surface of the conductor and the Electric Field inside the conductor is zero. Suppose we have a conductive sphere with charge Q = -4e. Where exactly in the sphere are these 4 electrons? I know that they are "on the...
  23. D

    Why don't charges fly off a conductor?

    To be concrete, consider two parallel conducting plates, one positively charged and the other negatively charged. Why doesn't the electric field between the two plates pull the charges off the surface of the two plates?
  24. Hardik Batra

    Is all the charge inside a conductor evenly distributed in equilibrium?

    As we know there is no charge inside the conductor.(Consider the solid conductor...) All the charge will distributed on the outer surface of the conductor. There is no charge inside the conductor My question is when we applied potential difference across this conductor then current will flow...
  25. J

    Magnetic field from a conductor using Law of Biot-Savart

    Homework Statement An electric current I flows in a straight conductor of length L. Use the law of Biot-Savart to find the magnetic field at a point lying on an axis going through the centre of the conductor and perpendicular to the conductor. Homework Equations Law of Biot-Savart...
  26. M

    How Is the Total Number of Charge Carriers in a Conductor Calculated?

    Homework Statement Let L be the length of the conductor having uniform cross-section area A and density, let I be the current passing through the conductor. How the total number of positive charge carriers in the conductor of length L is (nAL)?
  27. D

    Conductor wall with internal/external insulation

    Homework Statement Doing my homework I came across the question: why it would be better to have styrofoam on the inside of the house And why it could be better to have it on the outsideThe answer is The steady state will be the same for both but inside: warm and cold quickly Outside...
  28. S

    Are the electron flow in a conductor and ion flow in electrolyte same?

    A current flow occurs when there is movement of electron in a conductor. But in a electrolyte its the ions that move and we still say there is current flow. Are the electron flow in a conductor and ion flow in a electrolyte is the same?
  29. G

    B field inside conductor with assymetric cavity

    Homework Statement Infinite straight conductor, parallel with z axis, of radius R1 with a cylindrical cavity of radius R2. The axis of the cavity passes through the point <0,b,0>. A current I flows through the conductor. The current density is homogenous inside the cundoctor. Find the...
  30. S

    Plasma assumed as a perfect eletrical conductor?

    (Wasn't sure on the right section for plasma physics, I apologise if this is wrong).I'm reading up right now on a plasma surrounded by a tokamak wall, and the assumption of ideal magnetohydrodynamics - which assumes very little internal electrical resistivity and so the plasma can be assumed as...
  31. Y

    Boundary condition between conductor and free-space

    For an imperfect conductor, when there is current, an electric field is set up inside the wire along the direction of the current flow, and is parallel to the wire. If this is true, then what I don't understand is boundary condition tells me the tangential E-field is always continuous, if...
  32. Q

    Moving along a current carrying conductor

    What will happen if I move in the direction of drift of the electrons in a current carrying conductor? What would happen if my speeds are equal to the drift velocity and in a second case close to the speed of light
  33. S

    Geometric Mean Radius of Hollow Conductor

    Homework Statement GMR_{hollow cylinder}=Re^{-Kμ} where K=\frac{AR^4-R^2r^2+Br^4+r^4ln(R/r)}{(R^2-r^2)^2}, where R is the outer radius and r is the inner radius, and mu is the relative permeability. We are to determine the numerical values of A and B. I am stumped on how to begin attempting...
  34. C

    Can a second earthing conductor drive the fault current back?

    i have a TT earthing system and to decrease the resistance of the system I'm connecting the rods in parallel. i have the earthing conductor connected but as a mean of security, I'm thinking of connecting a second earthing conductor from the rod to the main Earth bar. Does this cause a any...
  35. Q

    Why is there force on a current carrying conductor?

    I know that charges experience a force when they are moving with respect to a magnetic field , but in case of conductor how is the force on the freely flowing electrons transferred to the structure of the conductor?
  36. baby_1

    Laplace in electromagnetics(voltages are different in conductor?)

    Hello as you see this example and solution if we assume the R of conductor sphere is 5m and check voltage in different z we obtain(for example z=1m and z=2) and as we know in conductor we doesn't have voltage differences so this equation should be the same C=0 but voltage...
  37. R

    Voltage on a conductor due to skin depth

    As we know due to skin depth effect the Alternating Current flows at a depth from the conductor surface (which means there is no voltage on the surface of the conductor, it is only at a depth from the surface). Then how is it possible for voltage to get appeared across some other conductor...
  38. D

    Charge above an infinite conductor

    Hello everyone! Homework Statement A charge, +q, is placed above an infinite conducting slab located at z<=0, at (0,0,d). Find the potential everywhere in space, without using the image-charge method. Homework Equations Laplace's equation(and its solution in spherical coordinates). (CGS units...
  39. C

    Good thermal conductor but insulator

    Hi, Does anybody know a material which is a good thermal conductor and an insulator at the same time (at temperatures around 4 K) and is "easy" to fabricate? For e.g. sapphire fulfils the first two requirements, but is extrmely hard.
  40. J

    Does an electric field go through a conductor ?

    I know there is no net flux in a conductor but do they go through the conductor? Say you have a positive q charge inside a hollow sphere that's charged pos q as well. Well that charge from the inner shell should keep penetrating space until it hits a negative charge which implies it goes...
  41. G

    What causes potential difference in the conductor?

    What cause potential difference in the conductor? I mean why the changing magnetic flux induce EMF? I understand the basics but I can't understand it. What I know: there is free electrons on the surface of a copper conductor. Electron have electric field vector and magnetic field vector and...
  42. T

    Neutral conductor has a hollow cavity within it

    Homework Statement a neutral conductor has a hollow cavity within it. When a point charge q = +6.3 nC is placed into this cavity How much charge will be found on each surface of the conductor? inner: -6.3 nC (negative charge being attracted by the positive charge that being put in the...
  43. S

    Why Is There No Internal Electric Field in a Neutral Conductor?

    Hello, members of physics forums. This is my first post and question. As such, it will be quite basic. In an electric field, a conductor with a neutral total charge is placed. All the charges in the conductor will be on the surface, negative charges against the external electric field, positive...
  44. R

    Electric field and the charged conductor.

    It is well known that under electrostatic conditions, a neutral conductor when placed in an external electric field encloses a net zero electric field within it. But, do you think that the electric field within a charged conductor is zero, when it is placed in an external electric field...
  45. M

    Potential of Concentric Spherical Insulator and Conductor

    Homework Statement A solid insulating sphere of radius a = 5.6 cm is fixed at the origin of a co-ordinate system as shown. The sphere is uniformly charged with a charge density ρ = -494 μC/m3. Concentric with the sphere is an uncharged spherical conducting shell of inner radius b = 10.8 cm...
  46. R

    Electric field inside a charged conductor placed in free space.

    It is true that under ELECTROSTATIC CONDITIONS, excess charge on a conductor always resides on the surface of the conductor because if they were inside it, there would be an electric field inside the conductor which would set the free electrons into motion. They distribute uniformly over the...
  47. L

    Calculating Electron Trajectory in a Parallel Plate Conductor

    Homework Statement An electron is fired at a speed vo = 5.6 ✕ 10^6 m/s and at an angle θo = -40° between two parallel conducting plates that are D = 2.5 mm apart, as in Figure P16.66. The voltage difference between the plates is ΔV = 103 V. Homework Equations F = Eq E = V/d a = F/m The...
  48. P

    Moving magnet and conductor - Residual worry

    This is about a famous thought experiment, cited by Einstein at the beginning of his first 1905 paper on SR, and discussed in textbooks and on this forum. I've fleshed it out with a specific set up, shown in the thumbnail. Seen in the S frame, a wire aligned in the y direction moves at speed...
  49. J

    Rotating conductor in magnetic field

    Homework Statement The problem consists of a single rotating conductor in a magnetic field as shown, I don't understand at which given numbered points where there would be a maximum and zero induced emf ? http://imagizer.imageshack.us/v2/1600x1200q90/28/7ggv.png The Attempt at a...
  50. Y

    Charged conductor in electrostatic equilibrium

    I have read that in electrostatic equilibrium, their are no electric fields or else the charges would be moving. So given a positively charged spherical shell, the positive charges would repel each other and reside on the outside, causing the shell to be in electrostatic equilibrium. But if...
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