Conductors Definition and 311 Threads

Homework Statement I just need help understanding what establishes a positive charge on the top conductor in C1: http://imgur.com/fppHtMN My book says that first there is a positive potential difference, Vab Homework EquationsThe Attempt at a Solution So since Vab is positive, a is at a...

Imagine an uncharged solid spherical conductor. Inside this spherical conductor, there is a cavity of a weird shape carved out of it. And somewhere inside this cavity, there is a charge +q (or rather, a charge distribution of total charge +q). The charge +q induces an opposite charge -q on the...

when the external electrical potential difference is applied across the conductor ,electrons flow in the direction opposite to the current.Whether the number of free electrons in the conductor decrease? I think ,No.As electrons return ,because they move in closed loop.

Homework Statement A hollow spherical conductor, carrying a net charge +Q = 47 pC, has inner radius r1 = 5.9 cm and outer radius r2 = 11.9 cm. At the center of the sphere is a point charge +Q/2. a. Find the potential at r = 18.0 cm. b. Find the potential at r = 10.0 cm. c. Find the potential...

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?

Hi, my ph.d. thesis is related to high temperature proton conductors. So, I would like to ask about proton conductivity measurement techniques. I know one, electrochemical impedance spectroscopy (EIS). Who knows more? Another question is about EIS measurements. Why conductivity measurements are...

Homework Statement Given two spherical conductors of radius R and tangent at O, both are charged and in equilibrium with surface charge density ρs=ρ0cos2theta. Calculate: a) Voltage of both spheres at O. (SOLUTION: V=2ρ0R/(3ε0) (...) Homework EquationsThe Attempt at a Solution So I tried to...

Homework Statement We have three equally long conductors with equali distance between each. I have simply drawn it badly. The difference is their currents, they all go in the same direction. How is the middle one effected? - It goes to the right - It goes to the left - It goes up from screen...

I’ve been reading about static electricity and storms and lightning conductors. I’m confused about the way lightning conductors work. Having read two sources and my questions are shown below: Source A (internet) Storm clouds have a negative bottom and a positive top. The bottom of the cloud is...

why does induced emf change in case of generators but remains constant in case of moving conductor?

CAn someone help me calculate expectation value of energy of electron in conduction band for semi conductor

I am desperate with an assignment and i would be grateful if someone could answer the following question. I read about skin effect and skin depth and i found the following one. "The skin effect depends upon the nature of material used for the conductor diameter of the wire, frequency, shape of...

Hi Something is bugging me a little. According to Maxwell's equations the magnetic and electric fields are decoupled in the static case, so that magnetic fields can exist in metals but not electric fields. For time varying fields, though, both fields are linked so that one cannot exist without...

I'm working my way through MIT 8.02x on EdX (an archived course, so it's a bit lonely in there right now!). The problem statement: Two spherical conductors, A and B, are placed in vacuum. A has a radius rA=25 cm and B of rB=35 cm. The distance between the centers of the two spheres is d=225...

A question has occurred to me during preparation for a Physics exam. My textbook does a good job of discussing a capacitor charged equal but opposite. But I want to take it a step further. My question is how to calculate the E field between 2 plates of opposing charge that have unequal...

the interior of a closed conductor can have no excess charges in the static situation ...and even if they have excess charge ...then these charge resides on the surface of the conductor...not inside it... can anyone explain to me...y a closed conductor behaves so? wht connection does it...

The problem is :The conducting spheres (s1) of radius R and (s2) of radius 2R of the figure shown are connected by a thin wire. The conducting sphere (s3) of radius R is connected to ground. A charge Q is placed on the sphere (s1). 1- Determine the charges Q1,Q2,and Q3 thus distributed on the...

Hi, I was hoping to get some pointers from you guys for references/ where to look to get help for the following: I want to know about the force that an electron experiences while on a conductor. When on the conductor, it's essentially in potential well. But i want to learn about all the...

I picked these questions below from a chunk of exams most of them are solved except this one. Questions 2 and 5 are confusing me. In question 2 s1 is supposed to be isolated and in 5 its not . if anybody can explain to me briefly what is happening or can solve them to me he will be so...

For an infinite plane sheet of charge it is obvious that the E-field points directly perpendicular to the sheet. but for conductors of irregular shape. say, a wire, or even a sheet with imperfections in it, what guarantees that the E-field will point directly perpendicular from the emanating...

Hi, Iam trying to understand the differences between metals, semiconductors and insulators. Regarding the conductivity properties. Iam new to this area so please correct me if I am wrong. I may be simplifying things now; 1) If I put a voltage over a solid, I only measure a current if...

I am aware that when charged particles accelerate or decelerate, the particle will emit a certain amount of radiation. But since a charged particle will accelerate any time it goes around a bend in a circuit, wouldn't it radiate some energy when it goes around the bend? I thought that giving...

Homework Statement Part (a): Show wave equation for E can be reduced to that. Part (b): Show impendance of material is: Part (c): Find skin depth. Homework Equations The Attempt at a Solution I've got parts (a) and (b) solved, part (c) I've worked it out, but I'm not sure...

Why do we need two conducting surfaces to allow TEM modes to propagate through a waveguide? Why can we not propagate TEM waves through a single conducting waveguide?

For two long, current-carrying, straight conductors in free space, the force of attraction (or repulsion) per unit length between the wires is the same. That is, the force per unit length experienced by the first wire, is the same as the force per unit length experienced by the second wire. But...

conflicting results. find the potential between the two conductors of a coaxial cable I have already found E... E = lambda / 2 pi r epsilon my question: What are the integration limits for finding the potential between the conductors? say we have a radius a (inner conductor)...

Consider two spherical hollow conductors, charged to Q1 and Q2 coulombs respectively. What happens when one is placed within the other, and they are connected by a thin metallic wire? I do know that if they were placed at a distance from each other, the charge is distributed in the ratio of the...

What are the properties and the parameters that govern the heat conductivity of materials?

A long straight metal rod has a radius of 5 cm and a charge per unit length of 30 nC/m. Find the electric field x cm away where distance is perpendicular to the rod.The solution to this uses ## \int E\cdot dA = \dfrac{q_{encl}}{\epsilon_0}##. My question is, why can you use this? I thought...

Homework Statement Ignore the text in German. You just need to see the picture. 2 conductors both with potential 0 are given. \alpha is the angle between the conductors. (r, \varphi) are polar coordinates pointing to a point in the plane. Homework Equations What we need to do is...

Hi I'm wondering why does the charge resides on the plates on a capacitor when it's charged but not on say two closely placed wires or circuit traces etc, well I do understand that charges stay on capacitor plates because the opposite charges tend to attract and with a distance between them they...

Hello, This is a sequence of my two last posts on this theme(i'm clearly messing this up in my head) and I got no clarifying answer on neither, so I'm trying here in the homework threads! Help if you know 100% sure otherwise its just going to get more and more confusing in my head because...

Find that capacitance of the system consisting of 3 dielectrics w/ length, l=1.0m, width, w= 1.0m and depth, d= 1.0 CM. ##k_1=1.5, k_2=2, k_3=2.5## *dimensions of conducting plates not given* Equations: Capacitance, ##C= Q/{\delta}V## Field in the dielectrics...

when current passes a conductor? does it also generate an electric field with a magnetic field? also what is the difference between the two fields?(i searched it up but i still don't get it) also are electric fields harmful to humans?(are they the same as radio waves?)

I have an enclosure that has numerous 18AWG cables running through it. These conductors carry 24VDC which power locking mechanisms throughout a building. The enclosure also has a 10AWG cable run to it carrying 120VAC. This is used to power the 24VDC power supply. The electrician wants to...

I've been doing some reading about the thermo-electric effect but I don't get why two different conductors are needed for the electrons to flow. I mean if I take a piece of copper wire and heat one end and cool the other, the electrons at the hotter end will get excited and move towards the...

Say I have a metal object and a wooden object at 0 degrees and I touch them. The metal object would feel colder because it is a better conductor of heat and so it removes heat away more quickly. Would it be because each collision between the atoms of the two materials increases the kinetic of...

A quick question. Let's say you had an infinitely long wire carrying a constant current, and a straight piece of wire parallel to it a certain distance away. Obviously, the current, being a motion of charges, will generate a magnetic field, with its curl being equal to the electrical...

Hello, I am trying to understand induction. If I have a negatively charged rod, and two negatively charged conductors, does no induction occur? or is the induction simply the movement of the electrons from the more negatively charged conductor to the less negatively charged conductor? or does...

So I'm a little confused. My question is: If a conductor is placed in an external electric field, do the field lines penetrate the conductor? My original thought was yes they do and then the induced field inside the conductor cancels out the external field so that the net field inside the...

Homework Statement Consider two conductors with capacity C1 and C2, separated by a distance d sufficiently large, so that each conductor can be considered as pontual, when observed by the other. Find the capacity coeficients and the capacity of the capacitor thereby formed.Homework Equations...

You place a conductor in an electric field. The charges inside the conductor will relocate, to form an opposing electric field which cancels the outside field, making the field inside the conductor zero. However, surely there's a limit to how big an opposing field the charges in the...

Homework Statement Two very long coaxial cylindrical conductors are shown in cross-section above. The inner cylinder has radius a = 2 cm and caries a total current of I1 = 1.2 A in the positive z-direction (pointing out of the screen). The outer cylinder has an inner radius b = 4 cm, outer...

1. A coaxial cable is powering a light bulb with a steady flow of current (DC current). The electric potential difference between the outer and the inner conductor of the cable is delta V and the current flowing in the cable is I. The inner conductor's outer radius is a and the outer conductor's...

I know that when there are excess positive charges in a conductor, for example, a metal sphere, the positive charges will spread out over its surface. However, I am confused about how this excess charge spreads out over the surface, if protons cannot move and only electrons can move. Can...

Hi! I have a question regarding the Faraday cage. I know how a Faraday cage works and understand the principles that make it work and why (potential difference, flux, gauss' theorem...) but I have a question. Why some Faraday cages work eventhough they have holes in their surface. For...

In conductors, how does the excess of positive charge distribute itself across the surface of the material?

I would like to know if anyone knows any good formulas for calculating the delay of impulses in single conductors twisted around each other when the period of the impulses is 1μs and the pulses are 20ns long. Some of the usual relations are no longer applicable in this case due to the very...

how do you prove that the electric field is determined uniquely from knowing the total charge on a conductor (just the outline of the proof). Thanks!

Hi guys, sorry as this is probably a silly question. This isn't homework, but it's something I'm confused about in my GCSE course. If a lattice of ions can't conduct electricity when solid, then why can a wire (composed of these lattices (I think?)) conduct electricity? The electrons in a...