In physics and electrical engineering, a conductor is an object or type of material that allows the flow of charge (electrical current) in one or more directions. Materials made of metal are common electrical conductors. Electrical current is generated by the flow of negatively charged electrons, positively charged holes, and positive or negative ions in some cases.
In order for current to flow within a closed electrical circuit, it is not necessary for one charged particle to travel from the component producing the current (the current source) to those consuming it (the loads). Instead, the charged particle simply needs to nudge its neighbor a finite amount, who will nudge its neighbor, and on and on until a particle is nudged into the consumer, thus powering it. Essentially what is occurring is a long chain of momentum transfer between mobile charge carriers; the Drude model of conduction describes this process more rigorously. This momentum transfer model makes metal an ideal choice for a conductor; metals, characteristically, possess a delocalized sea of electrons which gives the electrons enough mobility to collide and thus affect a momentum transfer.
As discussed above, electrons are the primary mover in metals; however, other devices such as the cationic electrolyte(s) of a battery, or the mobile protons of the proton conductor of a fuel cell rely on positive charge carriers. Insulators are non-conducting materials with few mobile charges that support only insignificant electric currents.
Hi,
I consider a connected conductor. Is it right, that:
1)the potential at any point of the conductor is the same, but
2)the absolute value of the potential isn't zero in general?
I think these statements are true, but I'm not sure about it, especially with the second statement...
Homework Statement
A line charge λ is surrounded by a long cylindrical insulator with a linear charge density 2λ and radius a. This is surrounded by a concentric conductor cylinder of radius b. Use Gauss’s Law to find the charge density on the surface per unit length at r = a just inside...
If a neutral conductor gets an induced charge and is then grounded, will electrons from the ground flow into the conductors induced positively charged side, resulting in a net negative charge for the whole conductor?
I've noticed that almost every good conductor of electricity, is also a good conductor of heat, except for certain exceptions like Graphite. Why is this so? I can't seem to associate electron flow with heat conduction.
Hey guys,
I'm hoping someone can help me out, as i have an exam tomorrow and have no began panicing as I've found a question i can't seem to get to the end of...
Here is the question itself;
A large crucible contains a metal of thermal conductivity, κ = 12.5 Watts. m-1.K-1, electrical...
If we have a very thin sheet of conductor, and a plane EM wave incident upon it from a vacuum, it goes into the conductor and starts dying exponentially. Another result is that the E and B fields of the wave aren't in phase anymore (see Griffiths).
Now, what happens when the wave reaches the...
1.Why electric field is zero inside a conductor? Can anyone explain it with Gauss's law and without Gauss's law?
2.Is it possible to create electric field inside a conductor? If so,how and in which condition it is created?
Hi
we all know that electric field inside a conductor is zero in electrostatic case. but this is
macroscopic field which is averaged over time and space coordinates. what about the instantaneous electric field inside the conductor. are there any experiments done to measure
this...
Homework Statement
A proton (q = 1.6 x 10-19C; m = 1.7 x 10-27 kg) is in a uniform 0.25 T magnetic field. The proton moves in a clockwise circle with a tangential speed of 2.8 x 105 m/s.
What is the radius of the circle?
Homework Equations
Not sure what equation to use.
The...
Hey All,
I'm new to the forum. I hope I put this in the right area of expertise. If not, I would appreciate it if you could direct me to the right place. I am just a curious person with a pretty good physics background but I came up with a question I couldn't answer. Hypothetically, if you had...
Let's say we have a charge a distance d above the xy plane, which is a grounded conductor. Find the potential at every point. Now this is not a hard problem if you know the method of images. I do however have some questions:
1) The idea is, as reader probably knows, to solve poissons equation...
i am really really confused . I know what Drift velocity is but the problem is I have three Sources which tell absolutely different expression for drift velocity and I cat relate . please tell which is right .
This website and MIT Profs. Walter Lewin In his Lectures says Vd = eE/m x (Tau)...
A conductor, like a metal string, is moving in an electric field.
The metal string is under mechanical tension and is electrically connected to a resistor. The other end of the resistor is connected to the remaining end of the string.
The electrical field is the static field of an electret...
Homework Statement
Fig. 1 shows the cross-section of an infinitely long conducting pipe. The inner radius of the pipe is r = R1, and the outer radius is r = R2. Suppose the inner surface has a constant voltage V = Vc > 0, and the outer surface has a constant voltage V = 0. The voltage...
This doubt cropped up in my mind while going through my old electrostatics notes...
We consider a spherical shell with some thickness (so that two different charge distributions may be possible on the inner and outer surfaces of the shell) made of some conducting material, and electrically...
Homework Statement
A conductor with inner radius R and outer radius 2R. A charge q is kept at a distance d<R but it is not at the centre. What will be the electric field outside the conductor? Will the charge distribution be uniform?
Homework Equations
The Attempt at a Solution
i...
Homework Statement
Prove that there is no charge inside a SOLID conductor, and thus, charges are only on the surface.
Homework Equations
Gauss's Law (Maybe)
The Attempt at a Solution
I have been doing some research on it on some websites.
It mentioned that, "you make a Gaussian surface...
Homework Statement
There is a conductor with a spherical cavity. Point charge B is at the center of the cavity. Point charge A is outside the conductor.
What is the force on B.
Homework Equations
The Attempt at a Solution
I know the answer should be zero, but I can't fully...
i've been thinking about creating some sort of taser like weapon. As we know, taser range is limited by the length of the wire and the weight of the electrode. So it's only usefull over short distance. What intend to create is some sort of stunner beam. Here's how it'll work.
the first part...
Suppose there is a cavity inside a conductor. Outside the conductor there is a point charge (A). E inside the cavity is zero because the field from the conductor and point charge cancel. That I believe.
Suppose I add a point charge (B) inside the cavity. Obviously, there is a radial...
Let's say we have 2 different conductors - one a round wire, another a round wire but with hollow core.
The wire with the hollow core has higher resistance. But for the sake of argument, let's assume that it has the same resistance and the round wire.
Will the skin effect be less for the...
Homework Statement
Two infinite plane lattices (conductor) of uniform thickness t1 and t2 respectively, are placed parallely to each other with their adjacent faces separated by a distance L. The first lattice has a total charge by unit of area (the sum of surface densities of each sides of...
Hello, I'm having some issues with Love's equivalence principle.
I'm studying Balanis' "Antenna theory" (1997), here's a (legal) fragment of the section in question:
http://www.uniroma2.it/didattica/ap1/deposito/02_2-Balanis-Equivalence_Theorems.pdf
I'm trying to understand the following...
Homework Statement
The figure shows an end view of two long, parallel wires perpendicular to the xy-plane, each carrying a current I but in opposite directions.
Derive the expression for the magnitude of B at any point on the x-axis in terms of the x-coordinate.
Homework Equations...
Homework Statement
Homework Equations
All explained in my solution attempt
The Attempt at a Solution
Let me know what's going wrong here. I don't feel like I should be getting something as small as t = .05 seconds for an answer.
I'm a little bit confused about this...i know that when a current-carrying conductor is placed in a magnetic field, it experiences a force called Lorentz force, this is the formula:
F = Bil
but the thing i can't understand is whether this FORCE is perpendicular to the magnetic field or the...
Hi was wondering if anyone knows how to calculate the tension in a overhead conductor say 'Dog' conductor over a 100m Span with a wind of 900Pa given its properties are as below
'Dog' Conductor properties
Diameter = 14.15mm
Weight = 0.3965kg/m
Area = 118.8mm^2
CBL = 32.7kN
Expansion...
how do i measure temperature of a current carrying conductor? i need to know the increase in temperature as i heat it up by passing a current through it. i read somewhere that i could use heat transfer convection equations to find it, but then i would need the precise value of the heat transfer...
Homework Statement
Calculate the drift velocity of the elctrons in a conductor that has a cross-sectional area of 8x10^-6m^2 and carries a current of 8A. Take the concentration of free electrons to be 5x10^28 electrons/m^3 with 1.6x10^-19C charge on each electron.
Homework Equations...
I'm attempting to figure out the total current induced in a hollow metal tube as a result of the EMF due to a constantly varying magnetic flux through its cross-section.
Faraday's law of induction states that for an infinitely thin loop of wire in such varying magnetic flux has induced EMF...
This is for extra credit not actual homework but I need the points and I would like to understand the subject matter as well so any help would be much obliged.
Homework Statement
There is a sphere with radius R made up of a perfect conducting material in a constant and uniform electric field...
Hi, I'm new to the forums, and I have a question.
Here's the scenario:
Let's say I have a circuit in a vacuum chamber with a current i, that flows through it and a constant voltage source and resistance in the circuit. One section of the circuit is a piece of gold (or any other conductor)...
Homework Statement
A 500 mm conductor inside an electric motor has a force of 1.5 Newtons exerted on it. If it is at right angles to a magnetic field of flux density 0.6 T, calculate the current flowing in the conductor.
Homework Equations
F=B.I.L
The Attempt at a Solution
B = 0.6T
F =...
Might have posted this in the wrong place before.
A metal wire slides on a horseshoe-shaped metal loop of width 0.25 m. The loop has negligible resistance, but there is a 1Ω resistor in the circuit as well as a 6 volt battery. There is a uniform magnetic field directed into the plane of the...
A metal wire slides on a horseshoe-shaped metal loop of width 0.25 m. The loop has negligible resistance, but there is a 1Ω resistor in the circuit as well as a 6 volt battery. There is a uniform magnetic field directed into the plane of the page of magnitude 0.5 T. The slide wire is pushed...
Homework Statement
The electric field is zero within the conductor because the charges are all at rest in an electrostatic situation. But the electric field inside a cavity within the conductor is not necessarily zero because it isn't part of the conductor, as my book says. Then i encountered...
If specs on a 300Hp electric motor;
480 Volts
3 Phase
60Hz
The full load Amps of the motor is 361A, which I found in the NEC table. My distance is 700ft to a control center and I can't seem to figure out what copper conductor size to use. In order to find the Voltage drop I have to know...
Hi everyone,
The field inside a conductor and also inside any voids in a said to be zero. I'm convinced with the available proofs for the field inside a conductor. However, I am not aware of any solid proof for the field inside a void in a conductor. Would you please share your knowledge on...
Problem:
Calculating the eddy current distribution inside an infinitely long cylindrical conductor inside a straight and infinitely long solenoid energized by an alternating sinusoidal current.
The problem has a perfect summery and we know that magnetic field and the eddy current depend on...
My textbook (Halliday & Walker) explains that a charged conductor (a solid, of an arbitrary shape) in electrostatic equilibrium will have the electric field inside be 0 and all electrons will be on its surface. It proves this by saying that if the electric field inside was not 0, the free...
Homework Statement
Hey guys, new to the forums so hopefully you can help. I have been given the frequency (and hence the wavelength) of a microwave of 10GHz, and the conductivity of Al which is 3.53x10^7 Siemens/m. From this I have worked out the skin depth. But it asks also what the...
Hi folks,
I am an electrical electronics student and hence you may find the question below ridiculously easy but please bear with me and I hope you could advise me.
I am currently doing a project and need to dissipiate heat away from a specific electronic component to the frame of the...
electric field "inside" conductor
Well consider a conductor with a void inside it. An external constant electric field is applied across it.
I would like to distinguish between two things : when i say "inside" the conductor i mean the void, the empty space which contains nothing but air and...
As we say that current is the flow of charges, but if we dye a conductor with red color and then connect the terminal with the dc source.
Now as the current starts flowing through this conductor and we say current is the flow of electrons or charges then why the red color around the conductor...
Hi, I was reading some text and came across this problem, the problem is also mentioned in this link from Wiki: http://en.wikipedia.org/wiki/Inductance#Self-inductance
They said that it is because the 1/R now becomes infinite, this is what I'm confused about. From my understand, there would be...
Imagine an uncharged spherical conductor centered at the origin
has a hole of some strange shape carved out inside it, and a charge
q is placed somewhere within this hole. What is the field outside the
sphere?
Is it even possible to determine the electric field simply from the given...
Homework Statement
In case of having a conductor (spherically shaped and uncharged) and an irregularly shaped hole inside it with a charge at an arbitrary point, I am asked to find the electric field right outside the conductor sphere.
Homework Equations
Gauss's law ∫EdA=...
Homework Statement
A hollow spherical conductor, carrying a net charge +Q, has inner radius r1 and outer r2=2r1 radius (see the figure ). At the center of the sphere is a point charge +Q/2.
A.Write the electric field strength E in all three regions as a function of r: for r>r2,r1<r<r2...
i can't grasp the idea that how is electrostatic induction possible in a conductor.
for example, if a negatively charged strip is brought near a metal conductor, the electrons will be repelled to the further end of the conductor thus making the end near the charged rod positively charged...
Hi there,
I have lately tried to revisit electronics again after a long hiatus. Unfortunately, I am having trouble with basics (which was originally what helped me to fail my post-school education).
I've always been interested in particles and their physics and have spent a bit of time...