Conductor Definition and 821 Threads

If a conductor has a cavity in it and if a charge is placed in the cavity, then will the electric field inside it be zer

1. The question: This question is from purcell's E&M book (3.71). (a) The plates of a capacitor have are A and separation s (assumed to be small). The plates are isolated, so the charges on them remain constant, the charge densities are +-σ. A neutral conducting slab with the same area A but...

Homework Statement The following is a small concept exercise from an. EM text (Electromagnetism: Pollack and Stump). I believe I have the explanations correct, but am just looking for "peer-review" as they seem "hand-wavy": Suppose a conductor has a cavity inside it, and there is a point...

I don't understand why there is no net electric field inside a conductor. Let's say the conductor is a sphere with excess charge. The charges will then distribute themselves towards the edges. Now, if I place a test charge anywhere except for the center of the sphere, wouldn't there be a net...

i have a doubt on this one. we know +ve charge (proton) and neutrons make the most of mass for any matter. Now consider a conductor and through induction, centre of -ve charged is moved toward the object (insulator(static charge on it) with +ve charge say). Now these two attract and conducting...

I was wondering , are there any materials , metal or others, that have ions as the charge carriers that form current instead of electrons as in most metals.? and are the ohmic resistance in room temperature for example similar to materials were current is formed by electrons or is the resistance...

Assume a conductor in a rectangle shape for simplicity. Now, if I only choose one side of this rectangle, and apply external electrical field ∑ only to it, what EMF would I create on the conductor? I would simply say ∑, however then I had the following idea, and I started to doubt if I create...

Homework Statement Through linear conductor flows current I, with direction shown in the picture. Axis where conductor is placed is common edge of three areas with different ferromagnetic materials. They form angles θ1, θ2, θ3 (θ1 + θ2 + θ3 = 2π). If space is filled with homogeneous materials...

Hi, this is my modified post since I've been told that I have to use certain format. I hope this is good now. Homework Statement Copper (conductor) sphere of radious R with an spheric bubble inside placed at distance c from the center, with radius b. The metalic sphere has charge Q.Homework...

I am confuse with the fact that current carrying conductor has gradual surface charge density which provide force to electron to produce current.

Homework Statement Wire conductor of length l consists of two part with equal length in series, and of specific conductivity σ1 and σ2. When conductor is connected to constant voltage U, what are electric fields in parts of this conductor? Homework Equations J=σE The Attempt at a Solution...

I have read Tesla's patent and he claims that by rarefying the air enclosed in a vessel its insulating properties are impaired to such an extent that it becomes what may be considered as a true conductor, although one of admittedly very high resistance.And any amount of electrical power can be...

Any one knows how to calculate the magnetic B field strength at a distance from a Large Conductor ? Do we go by average ? thanks

Homework Statement A conducting sphere of radius a is surrounded by a neutral conducting shell of radius b (b > a).Connections are provided as shown in diagram. Initially, the sphere has a charge Q. The switch S1 is opened and then closed. The switch S2 is then opened and closed. Finally, the...

Homework Statement A monochromatic plane wave with frequency ##\omega## and real amplitude ##E_0## passes from medium 1 to medium 2 orthogonally with the surface between the 2 media. Both media are semi-infinite; the indices of refraction are ##n_1=\sqrt{\mu_0 \varepsilon _0}## and...

Assume that we have a conductor of any shape, say a ball of copper. At electrostatic equilibrium, it is well known that the potential inside this conductor is constant, for otherwise free charges would move from points of highest potential to points of lowest potential (this includes the surface...

Assume we have the following copper slab, with volume ##V##, and introduced a magnetic field covering a small area of it like so: There is change in magnetic flux(##\phi##) due to the magnetic field increasing/decreasing, and via Faraday & Len'z law of electromagnetism, there is an induced...

for an electron, randomly moving inside a conductor , having applied an external electric field we have those electrons moving with a net speed called drift speed , against the direction of field. so initially as electrons are moving randomly we consider their initial velocity o and after time t...

i want to know why flow of electron produces magnetic field sombody says this is because of spin of electron or because of flow of charge or relativity of flowing electron. anybody please clear my confusion?

Homework Statement :[/B] When a steady current flows through a conductor, the electrons in it move with a certain average 'drift speed'. The drift speed of electrons for a typical copper wire is about 1 mm s-1 . How is it then that an electric bulb lights up as soon as we turn the switch on...

How to calculate condoctor size for different types of load like resistive load, inductive load or capacitive load etc and what will be neutral wire size for these load? Any body please help me. Thnx

Hello, this is my first post and I've been out of school for a few years and now working a job in my field at a distribution utility, but I'm just really rusty or green on a lot of things now that I'm being challenged. Seems like the simplest questions elude me! Anywho, I've been tasked with...

How come there's no electric field inside a metal cylinder, even though there's positive charge on side and negative charge on the other? For example look at this picture: As you can see there's is a zero electric field within the cylinder. Why isn't there an electric field that's directed from...

When current flows in a conductor, is it evenly spread out in the conductor? Not flowing(concentrated) in a certain part? And if we split the conductor into smaller pieces(visually not physically) the current divides out evenly so that when all those split pieces add up it equals the same as the...

So it says here that a conducting sphere of radius R with a charge Q uniformly distributed over its surface has V = Q/4πεR , using infinity as the reference point having zero potential,,V (∞) = 0. This gives C = Q/|ΔV| = Q/(Q/4πεR)=4πεR. Does ,V (∞) mean that you are taking the potential of a...

hello! is there a high thermal insulator material, like ceramics, that is also a good electricity conductor? or these two things, thermal insulation and electrical conductivity, are mutually exclusive? thanks!

Homework Statement If charged is place on a spherical conductor, it distributes uniformly. If charged is placed on a conical conductor, it does not spread uniformly. Homework Equations Remember that, in a conductor, the motion of electrons is fluid. The Attempt at a Solution Taking the given...

I recently studied Gauss' theorum according to which there is no electric field inside a closed conductor. But an isolated chage emits field lines in all possible directions. So why is it that there are no electric lines from the surface of the closed conductor inside it?

It's a dilemma I am in, I am stuck with definitions. NOTE: I have assumed that all the wires, have no resistance, there is not concept of antilog, etc. Capacitance in simple words, is the ability of a material to retain charge (and store it). Force due to charges, when a conductor is placed...

Imagine a surface charge ##\sigma##. The boundary condition on ##E## is ##E_{above}-E_{below}=\frac{\sigma}{\epsilon_0}\hat{n}##, where ##\hat{n}## points outwards perpendicularly to the surface. Because the field inside a conductor is zero, it requires that the field immediately outside is...

Homework Statement I'm having trouble understanding my book's explanation of the electric field within a conductor with a cavity. http://imgur.com/mjHRQoq Homework Equations EA = qenc/ε The Attempt at a Solution So I understand the first two pictures, the electric field is 0 because the...

In an example in my book, the author poses the following question: Given two large plates at a distance d from each other with arbitrary charges Q' and Q" (with Q' on the bottom plate and Q" on the top plate), how are the charges distributed on the plates? The author lists the following...

More specifically, the free electron density in increasing order goes like this: Ag Cu Al why then is the conductivity in the reverse order? ie the free electron density doesn't seem to play much of a role in conductivity beyond a certain point.

What will be the behavior of conductor at absolute 0 temperature?

Is the speed of electron flow through a conductor such as copper equivalent to 'c'? I've heard of this being implied several times, but is it a fact? I know it can't be exactly the same as 'c' because we are not talking of energy propagating though a vacuum.

Homework Statement Find the electric field between the conductor and ground. The conductor is at: Potential = +V0, radius a distance d from the ground plane. Homework Equations I used image theory to create a conductor at -V0 at distance -d from the ground plane. Laplace's equation: ∇2V = 0...

I don't know much about particle physics, but out of curiosity I was wondering what would happen if a stream of electrons hit a conductor, say copper plating, an would it be detectible?

Homework Statement How do I prove that a sphere is a conductor? Homework Equations E = kQ/rThe Attempt at a Solution In my mind, if a sphere is a conductor, the charges formed during induction will move to the surface of the sphere as they can move freely in the conductor, and the same...

According to electrochemical series ,gold is the last element thus it is depicted that it is the best electrical conductor.(most of the teachers say that) But according to the internet the best electrical conductor is silver , following copper and gold. Which one is true and why ?

I know the following works, but I cannot explain why. Say you have an infinite conducting cylinder (radius r=a) with charge Q/(unit length) in an electric field E. To find the potential, you just match the boundary conditions V=0 at a, and V→ -Er cosφ far away. Then you add in the potential of...

Homework Statement I was looking for some practice problems in my textbook and found this problem that I was just a little stuck on. I drew the diagram from my textbook with the givens of the problem. Homework Equations ∲E*dA = Q (inside) / ɛ0 The Attempt at a Solution For r less...

A point charge outside a hollow conducting sphere will produce no field in the hollow interior: the metal shields the interior. But a point charge inside the hollow interior will produce a field outside: the same metal ceases to act as a shield. Why is this? (In particular, aren’t “inside” and...

Here is the question that we have been debating for the past day or so: Take a conducting cubic box and center a conducting sphere with charge +q inside of it. Will the induced charge density on the sphere be uniform or not?My gut instinct is no. The cube and sphere have different symmetries...

Homework Statement I am trying to solve a problem from Jackson's book (in chapter 8). I must describe the propagation of a TEM mode through a transmission line that consists of two infinite conductor plates that are parallel to each other and separated by a distance a. There's a dielectric...

I was shuffling through the previous years question papers & I got this question ! '' A sensitive instrument is influenced by the strong electric field. Write a possible way to prevent this effect. Why is the electric field normal to the surface? '' I am not sure what the answer it. But this...

1. I'm a middle school science teacher with no science background, and I'm trying to avoid teaching any misconceptions on this topic! However, I don't know that I grasp what's going on here myself. I'm trying to explain rationale for why, on a circuit diagram, the symbol for a resistor may...

I can't understand this. When I think of a conductor I think of a cable, and last time I checked they are pretty static. So what is this "force" in practical use?

Is this correct? “The force that gets the electrons moving is the electric field. In AC, it is actually an electromagnetic wave traveling along the wire. Note that the electrons not only react to the electromagnetic field, but also are sources; the oscillating electrons themselves emit...

I have a confusing example that I'm studying, I tried to figure out the direction of induced current. But the right hand rule would tell me there isn't, but there has got to be since there is change in flux?! Here is the example: The gray bar is the conductor that is moving through a...

Homework Statement http://web.phys.ntnu.no/~ingves/Teaching/TFY4240/Exam/Exam_Dec_2008_tfy4240.pdf problem 2a) Homework EquationsThe Attempt at a Solution Hi. In problem 2a I was supposed to find a wave equation, however while digging around in maxwell's equations, I found this result...