Conductor Definition and 790 Threads

It is well known that under electrostatic conditions, a neutral conductor when placed in an external electric field encloses a net zero electric field within it. But, do you think that the electric field within a charged conductor is zero, when it is placed in an external electric field...

Homework Statement A solid insulating sphere of radius a = 5.6 cm is fixed at the origin of a co-ordinate system as shown. The sphere is uniformly charged with a charge density ρ = -494 μC/m3. Concentric with the sphere is an uncharged spherical conducting shell of inner radius b = 10.8 cm...

It is true that under ELECTROSTATIC CONDITIONS, excess charge on a conductor always resides on the surface of the conductor because if they were inside it, there would be an electric field inside the conductor which would set the free electrons into motion. They distribute uniformly over the...

Homework Statement An electron is fired at a speed vo = 5.6 ✕ 10^6 m/s and at an angle θo = -40° between two parallel conducting plates that are D = 2.5 mm apart, as in Figure P16.66. The voltage difference between the plates is ΔV = 103 V. Homework Equations F = Eq E = V/d a = F/m The...

This is about a famous thought experiment, cited by Einstein at the beginning of his first 1905 paper on SR, and discussed in textbooks and on this forum. I've fleshed it out with a specific set up, shown in the thumbnail. Seen in the S frame, a wire aligned in the y direction moves at speed...

Homework Statement The problem consists of a single rotating conductor in a magnetic field as shown, I don't understand at which given numbered points where there would be a maximum and zero induced emf ? http://imagizer.imageshack.us/v2/1600x1200q90/28/7ggv.png The Attempt at a...

I have read that in electrostatic equilibrium, their are no electric fields or else the charges would be moving. So given a positively charged spherical shell, the positive charges would repel each other and reside on the outside, causing the shell to be in electrostatic equilibrium. But if...

Hello Friends, in my textbook it is written that in electrostatics,electric field(E) due to a conductor at an external point very near to it is given by σ/ε.where 'σ' is the local surface charge density and 'ε' is epsilon.they have derived it by using a symmetrical conductor which have...

the title says it all , why does a changing magnetic field* or a moving conductor * induce a current ? i know the how , i know how it works ,i know that a changing magnetic field creates a changing electric field , but i want to understand how this works on the electronic level , what is the...

Homework Statement Show that, inside a straight current-carrying conductor of radius R, the vector potential is: $$ \vec{A} = \frac{\mu_{0}I}{4\pi}(1-\frac{s^2}{R^2}) $$ so that ##\vec{A}## is set equal to zero at s = R Homework Equations ## \vec{A} =...

Homework Statement Determine, whether germanium (sigma=2.3) is a conductor at the frequency of 2.4 GHz. sigma=?(omega)(epsilon) Homework Equations The Attempt at a Solution Well I know omega=2∏f and I have f. Thus I could find omega. Given sigma I could find epsilon but what...

Hello, I've been trying to understand how the fact of grounding a conductor affects its charge distribution. So, for example, let's assume there are three spherical shells with radius R1 R2 and R3. Supose I charge the R1 shell with q and the R3 shell with -q , and I connect the R2 shell to...

Could someone please illustrate the difference among the following terms? 1. Enameled round copper conductor. 2. Synthetic enameled round copper conductor. 3. Supper enameled round copper conductor. Thanks in advance.

say you have spherical metal conductor with a cavity with a positive charge inside, the field inside the cavity isn't zero and will induce an opposite charge/field on the surface of the cavity which will cancel the charge inside and lead to a zero Electric field inside the conductor. the...

Hi. Suppose I have 2 cylindrical bodies of the same radius and length - one is a good thermal conductor, while the other is a bad conductor. The upper end in each case is kept at a constant temperature T1, while the lower end is in contact with a steel disk of same radius, which is in free...

This is not an assigned homework problem, just something I came across. It's in Griffiths E&M book. Also I apologize if my equations don't look right. They are showing up all weird on my computer screen. Homework Statement A point charge q of rest mass mass m is released from rest a...

Please help me. Homework Statement Consider a metal sphere of radius R that has a total charge of Q. What is the force on one hemisphere by the other? Homework Equations F=E/q The Attempt at a Solution I thought the Electric field inside a conductor should be 0, therefore...

Hello people, I am doing some work where I need to look at a simplified situation regarding a conductor for which the conductivity distribution does not change along the z-direction of an infinite cylinder. The distribution itself is not symmetric in any way. Presume 2 infinitely long...

Homework Statement The current density in a cylindrical conductor of radius a placed along the z-axis is J=10e^-(1-ρ/a)Uz Find the current through the cross-section of the conductor. Homework Equations I=JA A=(pi)a^2 The Attempt at a Solution So far I have this...

What is "nominal Conductor diameter"(in generator winding)?

Hello everyone, One very basic thing about this phenomenon is not very clear to me. If a conductor moves in a region of uniform magnetic field, would it have an EMF induced across it? I'm confused because as per Faraday's law, a change in flux through the conductor is necessary for EMF to be...

That is what I wondering. When you put a ferromagnetic conductor in a strong magnetic field, the ferro conductor is strongly attracted because of induced strong magnetic dipole moments inside the conductor. My question: are all or (atleast a large portion) of the atoms of the conductor...

When a conductor carries current, due to Lorentz force, the conductor experiences a force. However I was wondering what causes electromagnetic induction. Moving a conductor in a magnetic field causes its charges to experience a Lorentz force, but unlike the case of the current, here both the...

Homework Statement http://imgur.com/sg8czUR An infinite sheet of charge has a charge density of σ= -2.1 uc/m2. (uc is micro-coulombs). The inner edge of the infinite conductor slab is 2.6 cm away. The outer edge is 4.2 cm away. The conductor slab has a charge density of σ= 74 uc/m2. What is...

Homework Statement A spherical conductor has a spherical cavity in its interior. The cavity is not centered on the center of the conductor. If a positive charge is placed on the conductor, the electric field in the cavity A. points generally toward the outer surface of the conductor. B...

Hi all, So I've been reviewing for the PGRE at the end of next month (wish me luck, I'm going to need it) and I stumbled across something that confused me in my old textbook. I was reading about the discontinuity of the electric field at the surface of a conductor, and also about the...

I remember seeing a demo of collisions inside a conductor. It was a long board with nails representing the atom positions (a square lattice arrangement) and you would put a hand full of marbles at the top. The marbles will slide down but since they keep hitting the nails the velocity will be...

I have a 400 amp 0-40 volt dc supply, I need to heat a wire by wrapping it around two bronze/nickel pulleys 12" diameter , with one connected to the positive terminal of the supply and one to the negative. The wire being mild steel .148" diameter moving at a rate of 50' per second with the...

Is resistor a conductor or an insulator?

In the absence of external forces, the electric field inside a conductor is supposed to go to zero. This is because if any field were to exist, then the charges in the conductor would experience force and continue moving until they canceled the field. However, is it true that for any system a...

Hi guys, can you please help me to understand the following question 1.Why the Electric field in a conductor in equilibrium ZERO?

Hello everybody! I read that if one of the two materials involved in Snell's law is a conductor, the refraction angle \theta_r is about \pi / 2 and is independent of the incident angle \theta_i (I think \theta_r will be precisely \pi / 2 if the conductor is ideal). My question is: why...

Homework Statement "Use the equation I=nAve to justify why charges travel faster in semiconductor than in metallic conductor. Assume that the dimensions and current are the same. " Homework Equations I=nAve I know I = current, n = number density, A= cross sectional area v= drift...

Homework Statement Find the total magnetic force on the semi-circular part of the conductor. There is a current I running counterclockwise through the semi-circle. The magnetic field B is out of the page.Homework Equations F = Il x B l = Rθ dl = RdθThe Attempt at a Solution I assumed that the...

i cannot understand why product of free negative and positive concentrations is a constant independent of the amount of donor and acceptor impurities. let say we dope in some n-type material (pentavalent) ,then the concentration of n should increase,but why ni2 still is constant ?

Homework Statement Begin from the expression of the electric field outside an infinite sheet of uniform surface charge density, E=\frac{σ}{2\epsilon}. Derive the electric field just outside an ideal conductor: E=\frac{σ}{\epsilon}. Do NOT use Gauss's law. Homework Equations Not sure...

can someone please provide me with a proof or even just an intuitive explanation

If an arbitrary shaped conductor is moving through a steady-state magnetic field, \mathbf{B}(\mathbf{r}), is it true that the field induced in the conductor will be proportional to \mathbf{B}? IE: \mathbf{B}_{induced}(\mathbf{r}) = M \mathbf{B}(\mathbf{r}) where M is a 3-by-3 constant...

All the metals are generally good conductors of heat. But is there a conductor for heat which drives heat without deviating or diverging through a fixed path as copper wires conduct electricity.

Homework Statement Use Gauss' Law to show that all static charge on a conductor lies entirely on the surface of the conductor. Homework Equations at a point outside the shell, this would be the final formula supposedly. E(r)= \frac{Q_s}{4\pi r^2 \epsilon} The Attempt at a Solution Sorry if...

Hi, I need help to understand these statements: The generators at the power plant can be operated as either, constant voltage source (CVS), or constant current source (CCS). To obtain a CVS, you spin the generator at constant speed. To obtain a CCS, you spin at constant torque. The CVS is...

I need help to understand what is going on in this simple circuit. Consider all voltage source, resistor and wire are ideal. And also assume that the wire has the same cross-section area along its length (A = const (m^2)). The voltage between two points A and B is defined as path integral...

For intrinsic semiconductor, the know its conductivity=2 neμ , where his the number of electron per cubic meter, e is the charge of an electron, μ is the electron mobility. But if I want to calculate the conductivity of a conductor= neμ. Why not consider the hole in? Electron leaves its...

Why is there a uniform current density in a conductor at DC. It’s my understanding that generally in a conductor, a sphere for instance, in a static situation, all charge is at the surface of the conductor because it the charges repel each other. So in a cylindrical conductive wire even though...

If a resistor shares common junctions to a conductor with no resistance in a circuit, will current flow through the resistor? Also, what is the equivalent resistance between A and B as in the figure...

so i plotted a graph for length of a conductor vs. the resistance to the corresponding the lengths. i observed two "peaks" on the graph. I am not sure how to explain it but it's definitely not a linear relationship. It's like a bunny bouncing diagonally toward toward +y and +x (But there are two...

Hi We know that the electric field at the surface of a conductor only have a normal component equal to ρ /ε (finite number). But let’s consider the point P (at the surface of a conductor ) . Assume that there is a charge at an infinitesimal distance from the point p . we can obtain the field...

Homework Statement three concentric hollow conducting shells are there . inner most is given charge +q , outer most is given charge -q and middle one is earthed , then find charge appearing on all the surfaces ? Homework Equations v= k q / r , E=k q /r2 The Attempt at a Solution no...

In an irregular shaped charged conductor will the electric field E at all points within the conductor be zero? If yes, then how?

I know there must be something wrong with the following derivation based on Maxwell's equations but could not figure out what is wrong. The derivation deals with continuity of current and free charge in a conductor in general. Continuity of current says that, \nabla\cdot...