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. K

    Charge sprayed onto a conductor

    An irregular neutral conductor has a hollow cavity inside of it and is insulated from its surroundings. An excess charge of 16.0 nC is sprayed onto this conductor. A) Find the charge on the inner surface of the conductor. B) Find the charge on the outer surface of the conductor. C) Without...
  2. T

    Why is the electric field inside a conductor zero?

    Homework Statement Why is the electric field, in static equilibrium, equal to zero. The Attempt at a Solution The only way I can see why is to picture that there was an electric field inside a conductor. The field would cause the electrons to move freely inside the conductor. This...
  3. Y

    Electric Field in a Conductor: Is the Image Misleading?

    The image below is from giancoli. There is clearly an electric field inside the conductor, going from the + charge on the outside surface of the wheel to the - charge on the inside surface of the wheel. There is an electric field inside this conductor because if I drop a + test charge in the...
  4. E

    Electric Potential outside of a spherical conductor

    Homework Statement The potential outside of a spherical conductor is given by V = keQ/r. Using Er = -dV/dr, derive the electric field outside this charge distribution. The Attempt at a Solution I attempted to take the negative derivative of V being -1/(r2) and then multiplying it...
  5. M

    Electric Potential due to a charged conductor

    Homework Statement Two charged spherical conductors are connected by a long conducting wire, and a charge of 22.0 µC is placed on the combination. If the first sphere has a radius of 4.49 cm and the second has a radius of 5.68 cm, what is the electric field near the surface of each sphere...
  6. R

    Electrostatic potential on the surface of a conductor

    Homework Statement At the surface of a conductor the potential is constant .. I can't get my head around this .. Homework Equations E=-grad VThe Attempt at a Solution The only reason I can think about this is Electric field is perpendicular at the surface , hence no work is done when moving...
  7. B

    Magnetic flux through a coil. Field generated by a straight conductor.

    Hi! I'm stuck on a problem concerning the magnetic field produced by a long straight conductor: A triangular piece of conductor (N=1) rests in the vicinity of a long straight conductor with a current I=50A. What is the magnetic flux through the triangle if a=1cm? (See attached file). My...
  8. C

    Add conductor between infinite sheet

    Homework Statement Please check attachment or picture below http://i.imgur.com/ALG5d.png Homework Equations The Attempt at a Solution Probably I should consider it as a capacitor? For a conductor, is that means no charge inside, charges are all on surface? Thanks!
  9. H

    Magnetic Field in a Cylindrical Conductor

    Homework Statement A cylindrical conductor of radius R = 2.49 cm carries a current of I = 2.17 A along its length; this current is uniformly distributed throughout the cross-section of the conductor. Calculate the magnetic field midway along the radius of the wire (that is, at r = R/2)...
  10. J

    What happens to field lines from a charge inside a hollow conductor?

    If I put a charge inside a hollow conducting body is it true that the field lines from the charge don't penetrate through the conductor but instead terminate at induced charges on its inside wall?
  11. P

    What happens when you connect a ptype semiconductor to a metal conductor?

    Will a current through the ptype + metal material be very low because of the ptype material? Does a junction like a pn junction form between the ptype semiconductor and the metal? Thanks for your time.
  12. A

    Different magnetic field in conductor

    hi all expert... During my study on physics book is borned in my mind this question: I have two conductors with the same material, same length and same diameter...In one conductor is carrying 1000 Ampere in A.C. and in other conductor is carrying 1000 Ampere in D.C. If i check the magnetizing...
  13. W

    Induced current in conductor moving circularly in constant B-field

    Homework Statement A light bulb with resistance R is attached on a metal rod which is rotating around the point O on the figure. The metal rod is in contact with an electrical conductor which is a part of a circle with radius d. The metal rod and the circular electrical conductor is a closed...
  14. D

    Mutual inductance in a Conductor

    Friends: Lets say you have a conductor that is made of two components - an inner core of steel and an outer layer of aluminum (ACSR). Is there mutual inductance between the steel and the aluminum? Every example of mutual inductance I have seen requires that an insulated wire be wrapped around...
  15. P

    Electric potential constant within a conductor?

    1. Electric potential inside a conductor / outside a coaxial cable Electric Potential inside a conductor(spherical) is a constant, although electric field is zero. How does that make sense given: Given V=- \int E \cdot dl? The integral should be 0. Even if you consider constants of integration...
  16. W

    Force on charges inside/out of a hollow conductor

    Homework Statement Two charges, q and q', are located respectively, inside and outside a hollow conductor. Charge q' experiences a force due to q, but not vice versa. Prove this statement and explain the apparently violation of Newton's third law. There is no net charge on the conductor...
  17. D

    Conductor Tension Due to Birds Landing & Flying Away

    Friends: I have been wondering how a conductor's tension is affected by birds landing on it and then flying away. By itself, the conductor has some tension obviously due to its weight. When a bird lands on the conductor, the tension increases. But what about when the bird flies away? By...
  18. R

    Charge on a grounded conductor w/ method of images

    Why is it that whenever the method of images is used to solve for the induced charge on a grounded conductor in the presence of a point charge, the total charge is just the same as the image charge?
  19. M

    Maxwell's equations on the boundary between non-conductor and conductor

    Homework Statement Hi, this is the first time I post a thread in this forum. I am not sure if I could post this question here since it is not a homework problem. I have trouble understanding two boundary condition between nonconductor and conductor from Maxwell's equations in dynamic case...
  20. R

    Resistance of a toroidal conductor

    Homework Statement Consider a segment of a toroidal (doughnut-shaped) resistor with a horizontal cross-section (see attachment for the figure). Show that the resistance between the flat ends having a circular cross-section is given by R = \frac{\phi_o}{σπ(√b-√a)^2} Homework Equations...
  21. I

    Effect of Neutral Conductor on a Point Charge?

    Why should the force on a point charge always be toward a neutral conductor? I know this is a simple concept, but I'm having trouble grasping it. Any ideas? Thanks!
  22. R

    A charged rod transfers electrons to a neutral conductor

    An initially neutral conductor contains a hollow cavity in which there is a + 65.0 nC point charge. A charged rod transfers - 75.0 nC to the conductor. Afterwards, what are the charges along the inner surface and the exterior surface? I understand that the charges from the rod are equally...
  23. W

    Exploring Spherical Conductor Current & Power Density

    Homework Statement A spherical conductor of radius a is surrounded by a spherical conducting shell of radius b, and the gap is filled with an insulating material of resistivity ρ. A thin wire connects the inner surface of the shell to the surface of the conductive sphere, and a potential of...
  24. C

    Help understanding voltage within a conductor

    Homework Statement Help me understand why electric potential can ever be a nonzero value at a point within a charged conductor? I need conceptual reasons to help me make sense of the integration "flaw". (See below.) Homework Equations The electric field inside a charged spherical...
  25. Demon117

    A rectangular hollow conductor, open at one end

    Homework Statement A rectangular hollow conductor,open at one end of z, has a voltage impressed at z=0. On the z=0 plane, the voltage as a function of x and y is simple cosines such that V=0 at x=y=+/-L/2. All other surfaces are grounded. V(x,y)\approx f(cos(Ax),cos(By)) Calculate...
  26. S

    Sliding conductor on a metal rail, with perpendicular B-field

    Homework Statement In the following diagram, the brown metallic conductor rod is given a slight push to the left. The black lines are all conducting wires, with the entire setup placed in a perpendicular B-field. Ignore friction. What will happen? 1) The rod slowly come to a stop? 2) The rod...
  27. A

    Why is there never any electric field in a hollow conductor?

    I can understand that if there is no charge inside an object then the electric FLUX is zero. Meaning the net integral of field vectors with respect to the area will be zero. But that doesn't mean there are no field lines inside the object at all! does it? I thought it just meant that the number...
  28. S

    The magnet and conductor problem.

    I am trying to understand the magnet and conductor problem that Einstein mentions at the beginning of one of his 1905 papers. In the frame of reference of the conductor, the magnet moves. Why does this mean that Faraday's law is applicable and not Lorentz force law? In the frame of...
  29. O

    What property of molecule structure can be a conductor - electricity?

    As we know, plastic is non-conductor, iron metal is conductor, does anyone have any suggestions on what kind of property in term of molecule structure allows electricity to get through? Thanks in advance for any suggestions
  30. Z

    Skin depth of a good conductor

    Homework Statement for my assignment given i was told to derive the equation of the skin depth of a good conductor and i derived it as d=sqrt(2/\mu\omega\sigma) then i was told to calculate d where i was given w=10^15 and sigma=10^7 and this gave me a d of d=1.26E-8 which i guess is...
  31. T

    Electric potential of a point charge inside a spheric conductor

    I'm trying to find the electric potential inside a thin (not charged) spheric conductor of radius R, containing a point charge of charge +q exactly in the center. To do this, I'm trying to solve the differential equation \Delta V = 0 (harmonic). Together with the boundary condition V(R) = c...
  32. S

    Electric potential, spherical conductor

    Hello, in this diagram, the shaded regions are spherical conductors. What's the potential at A=B? Ignoring the outer sphere, it should be kQ/R. When you add the outer sphere, potential at C=D=0 and electric field between B and C is kQ/x^2 so i integrated (kQ/x^2) dx with interval [2R, R]...
  33. B

    Potential of a charge approaching a perfect conductor.

    Homework Statement A point charge Q with mass M approaches a semi-infinite surface of a perfect metal and becomes trapped near the surface in a (quantum) bound state. Find the binding energy of this particle to the surface. Treat the metal classically—i.e. ignore its internal quantum levels...
  34. S

    Why is a Cavity Within a Conductor Important?

    This is an excerpt from my textbook. Could someone please help me understand why the line I highlighted in yellow is true? Thanks! :)
  35. jtbell

    Pity the poor conductor of this train

    ...having to call out the name of this station.
  36. H

    Charge on Conductor: Why Reside on Surface?

    why all the charges in conductor reside on surface?
  37. C

    E field difference between planar conductor and infinte sheet

    My question is related to the gaussian surfaces, a planar conductor and an infinite sheet. The E field outside of this sheet is sigma/2*epsilon naught The E field outside of this conductor is sigma/epsilon naught, twice as strong as the infinite sheet. I understand the...
  38. M

    Magnetic field inside and outside the rectangular conductor

    Hi I want to find the magnetic field result from DC current flow through the rectangular transmission line numerically by using the finite difference. the solved equation is curl curl A =µ J , with div A=0, and J is a uniform current on the crosssection. I implement the MATLAB code , but...
  39. P

    Electric field near the surface of a conductor

    Good afternoon, I was self-studying Electricity (Gauss' Law) and I have a doubt regarding the electric field near the surface of a conductor. I know that, near the surface of an infinite plate made of a non-conductive material, the electric field can be given by: E=\frac{\sigma}{2\epsilon_0}...
  40. sankalpmittal

    Why Copper is a Better Heat Conductor than Iron

    Hii , i am new in this forum . I am in class 10th and my name is Sankalp . I have a question : Can you tell me why copper is better conductor of heat than iron ??
  41. I

    Turning a conductor into an insulator

    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...
  42. S

    ElMag: Current-carrying Conductor, B inside a Hole

    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...
  43. F

    Induced emf in a rotating 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...
  44. F

    Current flow through no resistance conductor

    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...
  45. C

    Conductor in a Static B Field: Impact on Electron Orbitals and Induction"

    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.
  46. Z

    Liquid non metal conductor for railgun

    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...
  47. W

    Electric field inside conductor?

    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)...
  48. A

    Gauss' Law and charges placed within a spherical conductor

    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...
  49. E

    Caluculate Voltage Drop Due to Conductor Resitence on a Circut with an A/C Motor

    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...
  50. S

    Magnetic field inside coaxial conductor

    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...
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