Conductors Definition and 299 Threads

Hi all. I have a question regarding Gauss law. I have learnt that Gauss law applies irrespective of external charges. However, there is a situation which I can seem to reconcile. Consider the case of a coaxial cable, with two concentric conductors separated by a layer of air. The electric field...

Suppose we have two conductors ( can be of different shapes) and connect them to battery. Why would equal amounts of charge appear on the two conductors?

I have trouble researching whether valence-electrons take part in electrical conductivity. Some sources say that a lower amount of valence electrons lead to an higher electrical conductivity, whilst others say the opposite. And each have their different reasons, for example, lower valence...

Does the second uniqueness theorem just say that if there is an electric field that satisfies Gauss's law for a surface surrounding each conductor + a surface enclosing all the conductors, it is indeed the true electric field, and no other electric field will satisfy those conditions?

in this example in Griffiths' electrodynamics, he says the following :(Figure 3.7 shows a simple electrostatic configuration, consisting of four conductors with charges ±Q, situated so that the plusses are near the minuses. It all looks very comfort- able. Now, what happens if we join them in...

(a) Using Gauss's Law ##E_P=\frac{q_1+q_2+q_3}{4\pi\varepsilon_0(R_1+R_2+R_3+d)^2};(b) V_3-V_1=\int_{R_3}^{R_2}\frac{q_1+q_2}{4\pi\varepsilon_0 r^2}dr+\int_{R_2}^{R_1}\frac{q_1}{4\pi\varepsilon_0 r^2}dr=\frac{q_2}{4\pi\varepsilon_0}\left(\frac{1}{R_3}-\frac{1}{R_2}\right).## (c)...

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...

I teach electricity in grade 9. For the concept of conductors, they are described in the textbook as atoms where the outer electrons can easily move from one atom to another (e.g. copper). But I noticed that on the triboelectric series, copper and other metals are listed as having a strong(er)...

Hi guys, I wonder when I have defined the strand number of litz wire in copper material properities in Maxwell 3D, should I keep number of conductors in coil terminal added in a winding the same as number of of litz strand? For example, 2 for strands litz wire and then 2 for number of...

If there is a spherical conductor like this with excess charges on its surface then this is the field it sets up. Each e- would have there own radial field of lines. And all the e-s would exert a force on each charge and the net field on each charge and thus net force would be zero. All the e-s...

In this page you can see it’s written: E must be perpendicular to the surface. If it were not then the charges would move due to a component along the surface. I am assuming the field is generated due to the charges on the surface. I have a doubt. Is the author saying if it were not...

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?

Hello hope everyone at PF are keeping well! Looking at this problem but don't know if I have oversimplified it and my final answer doesn't seem right? So I drew the equivalent circuit: Then went onto calculate: I1 = 1/(R1+RL1) = 0.01A ω = 2πf = 2π*109 rads-1 so then with Vi being the inducted...

Hi, I found the following question in a physics book, and so dusted off my 30yr old knowledge on capacitors and tried to answer it. The question is as follows :- "Suppose two nearby conductors carry the same negative charge. Can there be a potential difference between them? If so, can the...

Is there any software/simulator of point charges/conductors? Preferably with features enabling dynamics of charges.

2 separate big conductors initially charged Q1 and Q2. Then connect them with an ideal wire (no resistence). The charges Q1 and Q2 will go to the 4 surfaces (marked red). All the 4 surfaces have an area A. Suppose the 2 conductors form an ideal parallel plate capacitor. How to determine the...

2 separate big conductors initially charged Q1 and Q2. Then connect them in a circuit with a battery of emf V. The charges Q1 and Q2 will go to the 4 surfaces (marked red). All the 4 surfaces have an area A. Suppose the 2 conductors form an ideal parallel plate capacitor and the wires in the...

I think: Due to charge q, there will be a field in region 1, very much dependent on position of q. The inner surface charge density of irregular conductor is also dependent on the position( so that it could cancel the field of charge and E=0 inside body of irregular conductor). The outer...

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...

Initially, I thought to apply the image charge theorem, but I don't know how to continue. Someone could give me some indication on how to solve the problem? Thank you.

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...

figure 1: → I don't understand how to approach this problem. Basically it asks for the distance r.I think I should use Gauss's law, but I've been thinking about the shape of the gaussian surface and I'm not sure about how it should look or where I should place it. Any help would be useful...

If I have two parallel bars serving as a DC bus with a capacitor across the output and there is a short fault event, I know the peak current is limited by V/X. The instantaneous current would be a function of the time RLC time constant. How do I relate this to the force on the conductors due to...

Here I am going to include the proof provided by my book. It is quite a splendid explanation, though there are a few key points I have yet to fully understand. If the electric force by the electric field on the charge at the surface of the conductor is conservative (which it is), then why is...

Are there any plausible semiconducting or superconducting devices which would show clear parity violation? Electrons in matter are governed overwhelmingly by electromagnetic interactions. Electron-electron, and electron-nuclei. However, there is in principle some weak interaction. Elastic weak...

Due to symmetry of the system,when the frame is rotated to make the electric field point from corner A to corner C,the magnitude of charges induced on these-(AB,BC,CD,DA),(OA,OC),(OB,OD) will be equal(different for each group but same for elements in these groups). For the sign of induced...

In order to find force( and hence the Acceleration) on the Pentagonal plate,we must find the Resistance of the plate.But to find the resistance we must know how the current is flowing through the given plate(see attached figure). My question is how is the current flowing through the Pentagonal...

The charges are q1,q2 & q. P,Q,O1,O2 refer to positions only. This is a conducting sphere with cavities containing charges. I'm interested in knowing how the charge should be distributed in the sphere. I know the charges induced on the charges of the sphere should be equal and opposite to the...

When placed in an electric field, a conductor has induced charges and a dielectric has bound charges. When there's no net bound charge density in the bulk of the dielectric, bound charges stay on the surface only, like induced charges in conductors. In Maxwell's eqs, the induced charges are...

How can I' be the formula above? Is there any formula to get this same

My first attempt at solving this was to calculate the induced charge in A by making ##V=0##: ##\frac{q_{A}}{4πεR_{1}}+\frac{q_{B}}{4πεR_{3}}=0## ##q_{A}=-q_{B}\frac{R_{1}}{R_{3}}## But that's not the answer. Any help is welcome!

The answer according to the key is C. I thought the answer would be E since the electric field inside a conductor is always zero. Can someone explain why the answer is C?

Hi, Here is a multiple choice question I am stuck with and would appreciate some guidance: The mark scheme for this paper says it is option A - 0N. I didn't get that at all. If a current carrying wire is in a magnetic field with some component perpendicular to the field then how can it be...

Hi! I need help with this problem. When the outer shell is grouded, its potential goes to zero, ##V_2=0## and so does it charge, right? ##-Q=0##. So the field would be the one produced by the inner shell ##E=\frac{Q}{4\pi\epsilon_0 R_1^2}##. When the inner shell is grounded, I think that...

I am seeking direction, information, resources and thoughts on the following subject. The common interpretation of the National Electrical Code does not allow you to use multiple smaller equipment grounding conductors in place of one larger one (except in a few cases such as a cable assembly...

Homework Statement Homework Equations The Attempt at a Solution I'm sure my solution is wrong because of Φ(z=0) ≠ 0 I searched the internet for a similar problem but I couldn't. Any help will be appreciated.

We can define complex permitivity of any medium as \epsilon=\epsilon'-j\epsilon'' And the loss tangent as tan \delta = \frac{\omega \epsilon'' + \sigma}{\omega \epsilon'} The question that I have is for good conductors. I read that for good conductors, we are dominated by σ rather than...

Hello guys! The electric field created by a conductor at a point $M$ extremely close to it is ##\vec{E}=\vec{E_1}+\vec{E_2}## where ##\vec{E_1}## is the electric field created by such a tiny bit of the conductor that we can suppose it to be a plane, and since ##M## is extremely close to the...

I'm considering two identical spherical conductor each of radius ##a## and separated by a distance ##d##, and trying to figure out the capacitance of this configuration. My thoughts are that since capacitance is $$C=\frac {Q}{V}$$ and that the spherical conductors are equipotential surfaces...

Homework Statement The following figure represent the traversal cut of a system with two cylindrical equal conductors of radius r0 length l at a distance d from one another and at the same distance h of a plane conductor (conductor zero). The dielectric that surrounds the conductors is the air...

Homework Statement I have a small question about the following problem. The figure represents the cross-section of a three-conductor system comprising a communications coaxial cable of length l running parallel to a conducting wall (reference conductor). Determine the partial capacitance scheme...

Homework Statement Two thin conducting spherical shells have radii R1 and R2.Outer shell is charged to q and inner shell earthed.Find charge appearing on both the shells. Homework Equations The Attempt at a Solution Isnt the charge on inner shell 0 and charge on outer shell remains Q as it...

Hello, Could someone help me find a general derivation of the formula for addition of capacitance of conductors? I'm hoping to find something that could be applied to a general assortment of conductors, not just parallel plate capacitors. I look forward to your response, Pete

Homework Statement If you put a capacitor in some circuit, why exactly do the conductors that form the capacitor have equal and opposite charge? This seems to be assumed in many cases. Homework Equations Is it possible for the conductors to have different magnitude of charge?

The electric field of an infinite conductor of net charge Q along the x-y plane is easily found using Gauss's Law: $$ \vec E(x, y) = \frac {\lambda} {2\pi \epsilon}\frac {[(x-x_c)\hat x + (y-y_c)\hat y]} {[(x - x_c)^2 + (y - y_c)^2]^3}, $$ where ##x_c## and ##y_c## mark the location of the...

I have a question with regard to split single phase (in United States) electricity. I understand that there are 2 hot legs each 180 degrees out of phase at +120v and -120v (240v between hot legs) going from transformer to breaker box and a center tapped neutral Earth bonded wire at 0v with...

Say I have two parallel conductors that are both L long and d distance apart (center to center). I run AC power of frequency f and RMS voltage V through one conductor. That current will create a fluctuating magnetic field which will pass through the the other conductor and generate a voltage...

Do ohmic conductors obey ohms law at high voltages? Also, I’ve seen it explained that some conductors are non-ohmic because the temperature caused by the current changes the resistance in the circuit. If that’s the case, isn’t ohms law still being obeyed, just with a varying resistance.

When we think of conductors in an abstract sense, charges can flow freely through them. What are these abstract conductors made of? I understand that conductors in the real world are made primarily of protons and electrons, But that it doesn’t seem like that is necesarrily the case. If we had...