Conductor Definition and 820 Threads

Consider an infinitely long stationary conductor which carries a steady uniform current. 1. At an arbitrary Test Point outside the conductor the Electric Field should be ZERO according to Maxwell's Equation. 2. But if Special theory of Relativity is considered, the moving charges...

Homework Statement A charge q of mass m is released a distance d from a semi-infinite grounded conductor. How long will it take the charge to reach the conductor? So I tried this using the method of images, and I can easily find the force on the charge a distance d away: F = -q^2 zhat /...

Homework Statement 13) A large metallic sphere insulated from ground is charged with an electrostatic generator while a student standing on an insulating stool holds the sphere. Why is it safe to do this? Why would it not be safe for another person to touch the sphere after it had been...

Homework Statement In the field of a point charge over a plane, if you follow a field line that starts at the point charge in a horizontal direction, that is, parallel to the plane, where does it meet the surface of the conductor? Homework Equations The problem 'hint' is "You'll need Gauss'...

1. If you have two identical conducting spheres A and C. A carries a charge and C is uncharged. Sphere C is touched to A. How does the charge change on A? 3. I know since C was initially uncharged, after it touched A it becomes charged. IF A was positively charged C would become...

why is the potential constant inside a spherical conductor/insulator? Are there boundary conditions that needs to be satisfied in order to make the potential zero? this is just a general question since most of the physics problems that I do needs the potential to be constant inside the sphere.

Hi, I have a doubt in my mind about the behaviour of Good Conductors. So far whatever we studied, 1. Good Conductors have free electrons to move and carry the charge, 2. Electric charge is being carried in form of electrons. Now the question is Suppose, we have piece of good...

[My understanding is that in a conductor which is conducting a current there is and electric field present also. If the electric field can be found by E= - \frac{dV}{dl}, what is E in a conductor. On a conductor in a DC circuit the potential is the same everwhere on that conductor, so I believe...

Homework Statement In a vacuum diode, electrons are "boiled" off a hot cathode, at potential zero, and accelerated across a gap to the anode , which is held at positive potential V0. The cloud of moving electrons within the gap(called space charge) quickly builds up to the point where it...

Homework Statement An isolated capacitor with capacitance C = 1 µF has a charge Q = 29 µC on its plates A conductor is inserted into the capacitor with thickness of the conductor is 1/3 the thickness of the capacitor and is centered in between the plates of the capacitor. What is the...

Anyone can tell me why there is a -ve for the z= -r cot theta for the picture shown below? thanks!

For insulators the excess charge stays on the outside of the object. For conductors the excess charge travels through the sea of electrons until the net charge inside the object is zero with the rest of the charges pushed to the outer edges of the conductor. So with both the excess charges...

Homework Statement In a vacuum, a straight conductor has 18-A current that goes upward. An electron is traveling at 8.92 x 10^4 m/s. If the electron is 0.2 m from the conductor and its instantaneous velocity is parallel to the conductor (albeit heading downward), find the magnitude and...

I have some questions about electric field inside a conductor. In fact, if a neutral conductor is placed within a capacitor, why its electric field inside the conductor at the beginning not zero, then it is zero? Why does the field disappear? How about if a charged conductor is placed...

Homework Statement Hi all. I have two questions. 1) The electric field of a uniformly charged, infinite plane is given by: E = \frac{\sigma }{{2\varepsilon _0 }} The electric field just outside a conductor is given by: E = \frac{\sigma }{{\varepsilon _0 }} Why are these expressions not...

A cylindrical aluminium bar is placed vertically on an insulating surface. The radius of the bar is R and the length is L. The bar has a total charge of zero. Compute the electric field inside and outside the bar. This is a Homework problem given by Count Iblis to the PF community :cool:

Why is it that the current in an ideal electric conductor resides in a very thin layer at the surface of the conductor?

Homework Statement A charge Q is placed at the center of a conducting spherical shell of inner radius R1 and outer radius R2. The sphere has no net charge. Ok, I have some statements for this setup. Would you be kind to check them? The Attempt at a Solution 1) The electric field in a...

Hi, As I understand it, the potential of a charged conductor is the work done in bringing a unit positive charge to its surface from infinity. Is this correct? When a conductor is grounded, then any excess electrons on it go into the ground. Is this correct? If so, why? Assuming that...

What is the difference, apart from the Meissner effect? What are the practical consequences of Meissner effect? How can I, by experiment, deduce whether a material is an ideal conductor or superconductor? superconductor has zero resistivity. So what happens when we apply a potential...

Homework Statement A 2.0-m length of silver wire has a uniform cross-sectional area of 0.6mm^2. If the drift velocity in this wire is 5.0 x 10^{-5} m/s and the electrons all move in the same direction along the wire. What is the total current carried by the wire? Homework Equations So...

Hi, Just got a doubt, which is probably silly but nonetheless cannot solve. Say you have a conductor placed in an external uniform electric field. We know that charges will be induced on the conductor and distribute on its surface as to nullify the field inside the conductor. Then, at...

Homework Statement http://img228.imageshack.us/img228/2536/physicsme1.th.png Homework Equations I = \int \int J . dS V = - \int E . dl V = IR The Attempt at a Solution I'm not really sure how to get started on this problem, generally I would start with Laplace's equation but...

Homework Statement A heavy conductor (mass m, length l, resistance R) is suspended by two springs each with spring constant k, and connected to a battery with electric potential V as shown in the figure. A magnetic field B is now imposed. The acceleration of gravity is 9.8 m/s^2. I'm going to...

Arright this appeared in my exam tommorrow and I was baffled by the question...Is there any way to store the charge in single conductor or the answer was "not possible" ?

i wanted to ask why the electric field inside a hollow conductor zero throughout and not just at the centre.

[SOLVED] Field of long cylindrical shell conductor Homework Statement Shown above is the cross-section of a long cylindrical shell conductor of inner radius a=4.00 cm and outer radius b=7.00 cm which carries a current into the page. The current density J (current/area) is uniform across the...

the field inside a conductor is zero therefore A. the potential inside the conductor is zero B. the potential cannot be zero C. The potential inside the conductor is the same as the potential just outside the conductor (on the surface) D. the potential inside the conductor cannot be defined...

Homework Statement Which of the following situations would result in a magnetic force on the wire that points due north? Check all that apply. Current in the wire flows straight down; the magnetic field points due west. Current in the wire flows straight up; the magnetic field points due...

We know that if current is flowing in the direction of z-axis (verical), magnetic field is formed in a plance perpendicular to that line i.e., in the XY plane. That is if you keep a compass in the XY plane it will experience a force as per the rule. But what will happen to a compass that is...

Homework Statement I have a slab of conductor on the ground with thickness, a, and it extends in all directions infinitely. Then I have a slab of insulator above the conductor of thickness, a, and it also extends infinitely in all directions. The two slabs are a distance, 2a, from each...

[SOLVED] electrostatics problem Homework Statement Two spherical cavities, of radii a and b, are hollowed out from the interior of a (neutral) conducting sphere of radius R. At the center of each cavity a point charge is placed--call these charges q_a and q_b. Why is it necessarily true...

Hi everyone, From this website (link: http://hyperphysics.phy-astr.gsu.edu/HBASE/solids/fermi3.html#c1 ), we get the following expression: Population Density of Conduction Electron = \int ^{\infty}_{Egap}N(E)d(E) = \frac{2^{5/2}(m \pi k T)^{3/2} exp (-E gap/2kT)}{h^3} My questions are based...

Hey everyone, first post and having an issue thinking about a simple problem. I'm into chemistry so I struggle to get all of these physics ideas down correctly. The problem is about a conductor with a neutral surface. The conductor has a cavity with a point charge of +P inside of it. A...

Do in conductor (like Cu wire) have electron holes, like there is in the semi-conductors?

I'm a little thrown off by this because we there is no voltage value given... And how does the air play into the problem? I just something to help me get started: What is the maximum amount of charge that a spherical conductor of radius 5.0 cm can hold in air?

I have the problem A positive point charge of magnitude 2.4 micro Coulombs is at the center of an uncharged spherical conducting shell of inner radius 65 cm and outer radius 85 cm. I have been trying to calculate the total charge for the inner sphere. I solved for the Electric Field by...

Hi This question really matters me and I would like to someone to point me out (rigorously if possible) why and what makes charge move in ideal conductor. All good conductors are modeled as being ideal so that the Maxwell equations inside the conductor needs not to be solved. So as electric...

How exactly do conductors conduct electrons? I'm confident with Maxwell's equations and I can accept a classical treatment like \sigma=\frac{nq^2\tau}{m} where \tau is the scattering rate. So actually I'd like to know what exactly happens with the electromagnetic fields when a voltage...

What makes the electrons move in conductor, while I am moving the magnet among the conductor in closed circular loop? It is the magnetic force from the magnet, but why when I get close the magnet they start moving in direction, oppose of the magnetic force?

Homework Statement Put in plain words: "In a static situation, the electric field at the surface of a conductor can have no component parallel to the surface, because this would violate the condition that the charges on the surface are at rest." Would this same statement be a valid one for...

Good afternoon(or good morning,it depends on where you are :zzz:),this is my first topic in this great forum so don't be very tough with me okay? My question concerns the means of producing electricity and to be more precise:Electromagnetism. I read that if you move a conductor(such as copper...

Hello everybody, I got a small question and was wondering if somebody could help me with that. Problem: I have a square conductor with side length m. I am now trying to figure out what the magnetic field B is at any point inside that square. Here is what I've come up with so far and...

Hello everybody, I got a small question and was wondering if somebody could help me with that. Problem: I have a square conductor with side length m. I am now trying to figure out what the magnetic field B is at any point inside that square. Here is what I've come up with so far and I think...

why is the magnetic field just inside a cylindrical conductor with inner radii a, and outer radii b carrying a uniform current I distributed throught it's croos section just 0 inside the conductor. I used ampere's law and that surely doesn't give 0

Imagine that there is a point charge in vicinity of an infinite grounded sheet of conductor of arbitrary shape and size such that the problem of finding the potential can be solved by using the method of images. Is their a way to prove that the total charge induced on this sheet is always equal...

Homework Statement Bill knows that a solution with an ionic salt dissolved in itwill allow a current to flow. Bill finds this quite interesting, so he finds a piece of plastic tubing and hangs it from an apparatus. He pours seawater into the tube until it is full. He then moves a magnet around...

Will the impedance characteristics for a length of stranded conductor be really close to an equivalent length of single core conductor? For example, can you expect the same impedance from a 20 ft. run of 12 AWG single core as you would from a 20 ft. run of 20 AWG stranded conductor? I know...

Why does the charge on a conductor accumulate at sharp points? I've read one or two explanations, but I don't follow them, and when I try to think about it I reach the opposite conclusion. Halliday and Resnick has an example where a large conducting sphere and a small conducting sphere are...

Hi Friends, I was thinking of having a either a point charge or some amount of charge at the center(let us say positive charge) and having a hollow concentric sphere( a conductor) around it. Now, there will be induced charge on the inside of hollow sphere and accordingly opposite charge...