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Questions tagged [conductors]

For questions about materials which allow the flow of an electric charge (electrical conductors) or the transfer of heat (thermal conductors) through them.

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1answer
119 views

Electrons close to Fermi-Conductivity

As a student of electrical and computer engineering solid state physics is not my thing so I might have fundamental blanks here and there. I really like this course and I try to gain as much as ...
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What is the significance of the height of these verical lines in Thermal Conductivity graph?

The following image is from the Wikipedia Article on Thermal Conductivity: Please click here if you want a good image resolution, as I was unable to upload it here due to "Unsupported Image Format". ...
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Surface charge on a resistive wire in DC circuit

I want to understand how does the energy transfered from battery to the resistor in a simple dc circuit . I read that it is due to the surface charge the battery creates on the wire. So why this ...
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Why does Griffiths's book say that there can be no surface current since this would require an infinite electric field for an incident wave?

In sec. 9.4.2 Griffiths shows the well known boundary conditions for E and B fields, one of them is this: $$\frac{1}{\mu_{1}}\textbf{B}_{1}^{\parallel}-\frac{1}{\mu_{2}}\textbf{B}_{2}^{\parallel}=\...
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How does 'conservation of law of energy' work in an open circuit connected to a hydroelectric generator?

I am trying to relearn high school physics and having trouble visualizing electricity in an 'open' circuit. I am going to use layman terms so i don't confuse myself! Apologies in advance if i am ...
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4answers
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Flux linkage inside of a conductor

Can someone explain to me why the flux linkage inside of a conductor is dependent on the cross sectional area of the conductor? My book says that d$\lambda$ = $(x/r)^2\phi$ where $\phi$ is the ...
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1answer
36 views

Can any other thing rather than current pass through conductor? [on hold]

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 ...
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1answer
50 views

Does the air conduct electricity?

If the air is compressed at high pressure in a container, then the volume of the air is less, therefore the air molecules are close to each other. If electricity is passed through the container, do ...
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2answers
386 views

Charged Cavity in conductor

Problem: Suppose we have an isolated spherical conductor and a cavity that is not concentric. Then, a charge is placed at the center of the cavity. What can we say about the distribution ...
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0answers
27 views

What exactly is a coefficient of friction due to electron stopping?

To be more specific, I am looking to understand what electron stopping is and how I could possibly define a coefficient of friction due to electron stopping. I am running MD simulations using LAMMPS ...
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2answers
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What will be the effect on Coulomb force if any conductor is placed between the electric charges?

I know that if any insulator or dielectric is placed between the electric charges then coulomb force decreases by factor known as dielectric constant.So, what will the effect when any conductor is ...
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1answer
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What would be tension developed in a conducting ring of radius $R$ which has been given a charge $Q $, uniformly in the ring? [closed]

As the question says , i thought about using coulumbs law , but for any small dq charge , all other part will be attracting it , so.how to get the total tension force ( difficulty is in as distance ...
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Gauss law in electrostatics

Consider a solid conductor,if the conductor makes a free electron inside that due to thermal energy ,so that causes one positive ion inside the conductor, my question is according to gauss law inside ...
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2answers
47 views

Charging a metal by friction

Why is it so difficult to charge a metal by friction, even if the metal is insulated? (For example, rubbing a fork hold by my hand wearing a plastic glove?) If I wear a glove, electrons can't pass ...
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3answers
49 views

$E$ outside a Metal Spherric Shell with a off-center Point Charge inside Shell

If a charge +Q is placed inside a metal shell (NOT at the center), as shown below. I can understand that E will be 0 between inner surface and outer surface due to this is a conductor. Then according ...
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Electromagnetism question about the magnetic flux and inductance of a parallel wire transmission line

I derived using the formula for the magnetic field of an infinite wire that the flux between the wires is the same as that in the answer but with $b-a$ on top. This is because when you integrate $B\...
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1answer
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Conductors and non-optical photons

While there seems to be plenty of information available about the photoelectric effect and the emission and absorption of photons by conductors (metals) at optical frequencies, I’ve been searching for ...
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25 views

Grounded Conductors and Charge

Not HW, just something that popped up in my mind during a shower XD Consider a configuration consisting of an insulator that has been charged negatively by friction, and a conductor placed nearby. ...
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3answers
69 views

Do electric charges in an electric field move at a constant speed?

The electric field is given by: $$\vec{E} = \frac{1}{q}\vec{F}$$ Electric charges create an electric field which, in turn, creates a force that accelerates charges. The Ohm's law, however, tells us ...
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3answers
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Drift velocity of electrons in a conductor

How does the drift velocity of electrons in a conductor depend on the temperature? I have two contradicting views for this. First, we can say that increasing the temperature of the conductor will ...
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3answers
420 views

Temperature distribution in a current carrying conductor

A rod of uniform cross section and composition is connected across a battery. Let the middle part of the rod(when divided into three equal parts) is heated uniformly. A book says that the temperature ...
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2answers
74 views

How could an ideal conductor with 0 resistance conduct electricity? [duplicate]

A very simple circuit consist of a resistor, a battery, and some conducting wires connecting the resistor to the battery(assuming resistance of the conducting wire is $0$). It is always assumed that ...
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2answers
28 views

On the microscopic description of a steady electric current

In Purcell's Electricity and magnetism, page 137, the author derived a formula describing the average velocity $\overline{\textbf{u}} $ of positive ions inside a conductor, a gas made of neutral ...
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1answer
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Why is the electron mobility 'irrelevant' in metallic conductors?

This Wikipedia article states in the introduction Conductivity is proportional to the product of mobility and carrier concentration. For example, the same conductivity could come from a small ...
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2answers
51 views

Why are 'low frequency' EM waves attenuated by a single layer of kitchen foil?

Can someone explain why my am radio doesn't work when covered by a layer of foil that is less than one 'skin depth' at the appropriate frequency? According to wikipedia and other websites on the ...
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3answers
482 views

Is an EMF more/same/less in an insulator than in a conductor?

Is an EMF (electromotive force) more/same/less in an insulator than in a conductor? For example: A loop of copper and a loop of plastic in a changing magnetic field. In which will the emf be the ...
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4answers
551 views

Car hit by a lightning strike

In Griffiths' Introduction to Electrodynamics, at the Electrostatics chapter, in particular, in the conductors section, he says this after the stating that within an empty cavity surrounded by a ...
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1answer
232 views

Interaction of charged particles with a conducting or insulating surface

If I have a charged particle floating in a vacuum, and it strikes a conductor or insulator on its way, what would happen? Would the electron be taken into the conductor? or would it just bounce off ...
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1answer
519 views

Location of mirror charges (method of images)

I was reading about method of images from Griffiths and I was thinking about a situation where a charge is kept inside a spherical cavity of a conducting shell rather than placing it outside a ...
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1answer
254 views

Neutral conductor and charged insulator brought near each other

What happens when a charged insulator is placed near an uncharged neutral metallic conductor? I know it attracts each other because of charging by induction (electrons redistribute). But would the ...
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1answer
32 views

On proving the $E$-field is null inside the layer of a conductor having a cavity

Let us consider a conductor having a cavity (both can have an arbitrary shape) wherein a positive charge $+q\,$ is located: At the electrostatic equilibrium, the inner wall of the conductor will ...
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2answers
50 views

A small size conductor causes a greater current in a circuit?

I have a question - let’s say I have a very small 2 wire cable connected to a load that draws a large amount of current, I’ve been told ( I have yet to do my own testing) that the smaller cable will ...
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1answer
138 views

Best visualization of electric current and voltage

I asked this exact question on the electrical engineering stack exchange, and it was suggested that I post it here: So, I want to know what the best way to visualize what is actually happening in a ...
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1answer
27 views

Can total charge be transferred from a conductor to another isolated conductor?

Suppose a conductor is charged (Total charge $Q$). Is there any method by which we can transfer the whole charge Q from the initial conductor to another uncharged isolated conductor? What another ...
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2answers
42 views

What makes electrons 'more free or less free' to move around?

I understand that conductors allow electron flow because their valence electrons are 'free' to move around.. But what exactly determines this 'freeness' and the lack thereof that separates conductors ...
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3answers
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What is “surface potential” of a conductor?

If there exists a charged conductor, the surface has a potential. This potential at a point on the surface is created by the charge distribution of all the other points on the surface. This means that ...
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1answer
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Is the electrostatic equilibrium that conductors reach a consequence of Coulomb's law?

We know that if charges were to be placed within a conductor, they would start to rearrange themselves until they reach an electrostatic equilibrium where all charges are 'still' and no $E$-field is ...
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1answer
462 views

Point charge inside a electrically neutral cavity in conductor placed eccentrically, and effect of external electric field if switched on

bear with me, but i would like a definite answer, now, starting off the external charge density on the outer surface of sphere WILL be uniform by unique solution of Laplace equation and letting the ...
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0answers
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Do charged conductors exhibit an equipotential surface even when subject to an $E$-field?

A charged conductor, in the absence of an electric field, attains an electrostatic equilibrium such that its surface has a constant potential. When a neutral conductor is placed in a uniform electric ...
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2answers
73 views

Why strong electric field leads to non-Ohmic behavior?

Homogenous conductors like silver or semiconductors like pure germanium or germanium containing impurities obey ohm's law within some range of electric field values. but if the field becomes too ...
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1answer
67 views

What exactly does Ohm's law say?

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points. Introducing the constant of proportionality, the resistance, R ...
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On proving that charge is linearly proportional to potential for a conductor

In Mr. Purcell's Electricity and Magnetism, page 103, it is stated, An isolated conductor carrying a charge $Q$ has a certain potential $\phi _{0}$, with zero potential at infinity. $Q$ is ...
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274 views

Conduction and Ionic Conduction

How the ionic conduction is different from normal conduction ? Does the electrons that leave atoms completely conduct in ionic conduction while in normal conduction the conduction takes place through ...
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1answer
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Is the $E$-field near and on the outer surface of a conductor null?

Let us say we have a conductor the outermost surface $S$ of which is given by $$S: \big(\,x(u,v),\, y(u,v),\, z(u,v)\,\big )$$ where $u$ and $v$ are parameters. Since it is a conductor, the ...
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Creation of electric field inside a conductor

My book says that as soon as the two ends of a conducting wire touches the two terminals of a battery, it generates an electric field inside the conductor. Why?
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67 views

Movement of free electrons

How can I understand the movement of free electrons in a conductor taking into account the quantam mechanical approach of electrons i.e. uncertainty of position and momentum etc. Does using quantum ...
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2answers
296 views

Why does electrostatic potential inside a conducting spherical shell seem to violate superposition principle?

I want to find the potential at the centre of a conducting spherical shell; The conducting shell bears a total charge of $Q$. The shell has a radius $R$, and there is a point charge of magnitude $q$ ...
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Speed of light vs speed of electricity

If I arranged an experiment where light raced electricity what would be the results? Let's say a red laser is fired at the same time a switch is closed that applies 110 volts to a 12 gauge loop of ...
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6answers
159 views

Why is it assumed that magnetic forces arising from magnetic fields do not do work on a current carrying conductor?

Imagine a long, thin current carrying conductor carrying a current $I$ and moving through space with a velocity $\mathbf v$. If there exists a magnetic field such that there is a force on the current ...
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1answer
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How do I calculate the surface potential of a conductor given a charge distribution?

I have tried the conventional definition but since there is a charge density at the point we want to calculate the potential at, it turns out to be infinity. Now, i dont know how to calculate the sum ...