# 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. ### I EM field and EM wave

Hello, I'm new to this forum. I have a short question that I can't solve on my own, I've consulted many books but I can't find solutions, I hope you can help me. Then considering a conductor traversed by an electric current that varies over time, it produces an electromagnetic field, under...
2. ### I Quantum Hall Effect and Hall Voltage

I understand that the Quantum Hall Effect explains how both the transverse and longitudinal resistance vary with magnetic field strength. I don’t get why the hall resistance is equal to the hall voltage over the current . I know current isn’t a vector quantity but isn’t the hall resistance an...
3. ### Direction of electric field vector on the surface of charged conductor

Consider a negatively charged spherical conductor. On the surface of it, what is the direction of its electric field? Well, the definition of the direction of an electric field is the direction a positive test charge would go if placed at that point. But... it wouldn't move anywhere! So is the...
4. ### Zirconium Versus Zirconium Carbide For Use With Galinstan

I'm planning on working with galinstan, for one of my projects. I need a conductor that can be immersed in the galinstan, indefinitely, without being corroded. I've learned that zirconium carbide has excellent chemical resistance, when it comes to galinstan. However, no one seems to sell it...
5. ### I Current's Effect on Electrical Arcs

Hello, I figured this belongs more in a physics thread than an electrical engineering thread, but please advise I am wrong. I am having a hard time finding the correlation between the amount of electric AC current flowing in a conductor and its affect on allowing an electric arc. Obviously the...
6. ### Electric field on the axis of a ring-shaped charged conductor

Hello. I was wondering why do we not multiply cos(alpha) by 2. I believe we should do this since the y-components of the electric field cancel out, meaning there would be 2 x-components of the electric field(at least I think so). Currently, this derivation/answer only considers one horizontal...
7. ### Conductor Cross Section: Small vs Large Copper Wire in 9V Battery Experiment

I connected the small copper wire and the light to a 9V battery, the light came on, but when I changed to the large copper wire, the light did not light up.
8. ### Gauss' law and Faraday cage problem

Is this a good response? The lift is a conductor, therefore electrons can move freely. The charges on a conductor reside on the outer surface as they like to be as far from each other as they possibly can be due to the repulsive coulomb force. There is no charge between the inner and the outer...
9. ### Heating of a conductor (1000 turn coil)

Suppose I have a current carrying wire that is 20 AWG copper. There is insulation on the copper wire that is rated for 200 degrees C. I have 500 meters of the wire wound into a coil. The coil takes up a total volume of 0.0001157 meters cubed (roughly 1000 turns). Suppose I run 3 amps of current...
10. ### Electromagnetism: Moving conductor and EMF

For 1) I used $$V=Blv=Blwr$$, where $$w= \frac{4\pi rad}{sec}$$, $$l= 0.30m$$ and $$r=0.50m$$. I got 0.5 V. For 2) I used W=Vq=VIt, where $$q=It$$, where t=0.5 s, we get 1.125 J. For 3) I used P=IV, we get 2.25 W. Are these correct?
11. ### Conductor rolling down an inclined plane in a vertical B-field

For part (c) of this problem, My working is However, the tricky part is to find theta. I tried to draw the situation so that I could find theta: It appears that theta = 90 degrees. However, this does not seem to be correct. Does anybody please know how to correctly find theta in terms of...
12. ### Magnetic Field Surrounding a Straight Conductor

For this problem, Part of the solution is, However, would someone please tell me where they got the sine function circled in red from? Many thanks!
13. ### B Uniform charge distribution in a conductor

How and why can charge be evenly or uniformly distributed in a conductor? How can such near perfect configuration of charge be achieved? Is outside influence (or force) or any special scientific tools or instruments required to accomplish that? By definition, electrostatic equilibrium is...
14. ### Ampere's Law for Cylindrical Conductor

I know that Ienl for the inner cylinder is just I and the current density for the outer tube is J1= -I/(pi(Ra^2-Rb^2). I assume that the current through the enclosed portion of the conducting tube (I1) is equal to J1(A1) where A1 is the area of the enclosed portion of the conducting tube. I...

A faraday cage made of a perfect conductor would theoretically have a zero E field inside. However, are there cases where a faraday cage made of a real conductor like copper wouldn't block out all EM radiation, like very high or low frequencies? How can the design be improved to make a real...
16. ### I Questions about a Conductor in an Electric Field

Dear PF, I have a question regarding a conductor in electric filed. I have formulated my question in attached PDF file ... would please be so kind and advise me please... Thanks you in advance ...
17. ### How is converted the energy of a E.M. wave in a conductor

I'm thinking about how the energy is conserved when a E.M. wave pass through a conductor. If a E.M. pass through a conductor, the electrons must move "oscillated", thus the energy from the E.M. wave is converted to kinematic energy. Another way I see that is the E.M wave must generate a current...
18. ### I A smaller cross-sectional area increases the resistance of a conductor?

why smaller cross-sectional area increases the resistance of a conductor?
19. ### Charge density on the surface of a conductor

I have tried to solve the problem by setting as a condition that the electric field inside the conductor has to be 0, but in this way I have two unknowns (σ1 and σ2):
20. ### Uncharged conductor inside an insulating shell

I worked this problem out in griffiths and my work checks out for for the potentials, b.c. and the coefficients. I will post the solutions just because my work is a little harder to read. What I am having trouble finding is the dipole moment of the conductor. I know the formula for dipole...
21. ### I Electric field is zero in the center of a spherical conductor

Electric field is 0 in the center of a spherical conductor. At a point P (black dot), I do not understand how the electric field cancels and becomes 0. Electric field is in blue.
22. ### I Why is there no induced charge outside of the conductor?

If we put a positive charge outside of a conductor, there is an induced charge, but if we put a positive and negative charge inside a conductor, there is no induced charge?
23. ### I Electric field, flux, and conductor questions

1) Why is the electric field 0 at the bottom of Gaussian surface? Isn't the electric field on both sides of the surface, pointing down and outwards like a plane of charge? see image. 2) Why does a charge distribution with cylindrical symmetry have to be infinitely long? 3) My book says a...
24. ### Point charge in cavity of a spherical neutral conductor

For (a) this problem, the only thing I can see changing is the distribution of the negative charge on the inner wall of the cavity. When the point charge is in the center of the cavity, you could say the induced charged is spread symmetrically on the inner cavity wall in order to oppose the...
25. ### Question About a Test Charge Near a Conductor

I am confused because I thought this was a method of charging a conductor. Why would the system be reaching a state of equilibrium?
26. ### I Visual Interpretation of Advanced Electrodynamics

Hello! I am a junior undergraduate physics major and I am very confused on how to visualize things in my electrodynamics class. Specifically, I am having issues with dielectrics and spheres with constant potentials etc. I usually notice that I am lost in a class when I can no longer draw out a...
27. ### I Perfect conductor in rotating magnetic field

Hello all, what would happen to a perfectly conducting cylinder immersed in a rotating magnetic field, with the rotation axis parallel to that of the cylinder? I guess the cylinder would start to rotate with the field? Right? Thank you
28. ### I Why does increasing resistance in a conductor decrease power dissipation?

I read that resistivity is related to the mean free path of electrons inside the material and on density of charged within it. The electric field does work to flow electrons through a resistor, and the energy is converted into heat due to collision with lattice ion, right? ( in free space they...
29. ### Uneven charge distribution on a conductor

All I can say is that where the charge density on surface is higher, we will have a stronger electric field compared to areas where charge density is lower since more charges means greater electrical force on a test charge placed very close to the surface. Also, the potential on pointed areas...
30. ### Violate current conservation in Perfect Magnetic Conductor (PMC)

Hello, I need to know why having an electric current in Prefect Magnetic Conductor(PMC) violate current conservation. Based on the boundary conditions or lorentz force or ..., I couldn't be successful to prove that surface current can violate current conservation. In the textbooks, they...
31. ### Potential outside a grounded conductor with point charge inside

Potential inside is given as in ,https://en.wikipedia.org/wiki/Method_of_image_charges, which is the sum of excitation and induced potential. When the charge is outside it is easy to argue potential is zero in the sphere. But when we have charge inside and image outside, what is potential...
32. ### I How do point charges in a conductor move and stop?

Let's speak in the classical context (non quantum). We assume that point charges move in a conductor following Newtonian mechanics. How do point charges move along the boundary of the conductor and how do they stop (equilibrium) in the end?
33. ### Identifying which region in the conductor experiences a greater force

I feel that its M because as the conductor moves upwards, towards K, an equal but opposite force will be produced at M to pull the conductor downwards, but answer is K.
34. ### Identifying which region of a conductor experiences the greater force

I feel that its M because as the conductor moves upwards, towards K, an equal but opposite force will be produced at M to pull the conductor downwards, but answer is K.
35. ### B The resistance of an ohmic conductor

I know that the resistance of an ohmic conductor increases with length because the electrons going through the conductor must undergo more collisions in a longer conductor. But why decreasing the cross-sectional area of the conductor also increases the resistance of a conductor?
36. ### Why Doesn't Electric Force Cause Wires to Move?

Hello, In the section of Magnetic Force on a Current- Carrying Conductor in the book of College Physics by Serway, it is written that the Current- Carrying Conductor in a magnetic field deflects because the magnetic force on the electrons transfers to the bulk of the wire due to the collisions...
37. ### Induction in electrostatic equilibrium conductor

We know that both the interior and the surface of an electrostatically balanced conductor are equipotential. My question is if when we approach the loaded objects, the surface of the conductor will continue to be an equipotential. If not, then there could be a field line that left the region...
38. ### Whether charges can stay inside wires or on the surface of a conductor

There's an isolated capacitor initially carrying nonzero net charge. Then place the capacitor in a circuit connected with ideal wires (no resistance). Where will the excess charge go? Can they stay in wires or on any surfaces of conductors in the circuit? Electric field needs to be 0 everywhere...
39. ### Electric Field Shielding: Does a Conductor Shield Inside?

Hi. I was reading about conductors in electrostatic equilibrium and how it makes sense that they have zero electric field inside the material even when an external charge is brought near. The charge density of the material just rearranges itself to cancel. Then I searched for hollow conductors...
40. ### E-Field immediately outside a charged conductor

Griffith's says this, and I'm not exactly sure why... If you had a solid, spherical, and externally induced conductor... Does this mean that IMMEDIATELY outside, when you're infinitesimally close to the surface, E looks like this? If you surround the entire conductor with a Gaussian surface...
41. ### Work done via induced charges in a grounded conductor

I'm currently studying Method of Images in Griffiths book and in section 3.2 he introduces the method of images for a point charge at a distance ##d## from a grounded conducting plane at potential ##V = 0##. In subsection 3.2.3, Griffiths compute the energy of the real system and the image...
42. ### Location of electrons (not excess charge) in a conductor [static case]

In a conductor, excess charge resides on the surface. That seems odd, because one would think that the overall energy of the system could be lowered by allowing some of the excess charge to move inward and away from all the charge on the surface, but obviously that can't be true, because charge...

44. ### EMI Shielding Effectiveness with Various Conductor Thicknesses

Let's assume that I have have one conductor carrying current to the load in one direction and the return line with current in the opposite direction from the load. If the current has high di/dt due to switching, may have EMI issues with nearby circuits. I know that I can put a "ground" plane on...
45. ### Characterizing Total Charge of Conductor A in an External Electrical Field

Assume that a certain charge distribution ##\rho## generates an electrical field ##E_{ext}## in the surrounding space. We also note the corresponding generated potential ##V_{ext}##. Assume furthermore that a conductor A, with a definite shape and volume, is placed in field ##E_{ext}##, and is...
46. ### I Room Temp Super Conductor: Break Out the Champagne?

Summary is from abstract in Nature. Anybody know whether this is a big deal ?. It looks technically challenging (very high pressure) but great oaks from little acorns. I'm not current in superconductivity.🔎...
47. ### The electric field inside a hole inside a conductor is still 0?

This is not a homework question but something that bugs me a bit. My professor has stated that the electric field inside a conductor is 0. This I understand. However, he has also said that even if the conductor has some hole in it, the electric field inside this hole is also 0 Now, two...
48. ### A Taking all the electrons away from a real conductor

How many electrons can you remove from a solid substance before it breaks down at a chemical level? Thinking this through myself, you can create positively or negatively charged objects to a degree, especially with a metallic conductor that can tolerate a loss of charge at the cost of the...
49. ### Magnetic field of a straight current-carrying conductor

It is not a direct home work problem, i was thinking if a sine wave current passes through the straight current carrying conductor, what will be the magnetic field. For the DC current I know the formula as below. ##B = \frac {\mu_0 I 2a} {4\pi x\sqrt{x^2 + a^2}}## Let the current be ##I =...
50. ### How will electrons flow in a very long conductor?

I have two charged spheres connected to different ends of an infinitely long conductor. The first sphere has positive charge, another sphere has negative charge. Suppose that the electric field of the first sphere at point A is zero, and the electric field of the second sphere is zero at point...