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.

122 questions
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Skin effect fully explained by plane wave attenuation?

I went over the explanations of the skin effect in multiple sources. However, I still don't understand how the fact that this equation: \begin{equation} (\Delta - \mu_0\sigma\partial_t - \frac{1}{c^2}...
733 views

How to calculate Hall coefficient in gold and silver?

BACKGROUND - Hall Effect Using the free-electron model, the Hall coefficient is calculated as $$R_H = \frac{1}{ne},$$ where $e$ is the elementary charge and $n$ is the carrier density. For a metal $X$...
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what is the current operator of an interacting electron gas?

If i have an electron gas with coulomb interactions, what would be the current, operator. I would write the Heisenberg equation of motion for the density operator, than write the continuity equation ...
120 views

Van der pauw method for an isolated hole

Van der pauw method is a way to measure the resistivity of a material with arbitrary shape while it meets some specifications ( being homogeneous and ...). One of the conditions is that the sample ...
248 views

Electric field in a “concave” conductor

I am aware that the electrons are distributed across charged conductor surface so that the areas with smaller radius of curvature have more charge per surface area. But what happens when the ...
26 views

Exact distribution of electric field in conducting current carrying cylinder

Consider a conducting cylinder, whose place surfaces are connected to a battery. Now, if we assume electric field inside it is constant, and electric field just outside it is zero, then circulation of ...
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I was thinking about the Hall conductivity, when this question popped up. If there is a magnetic field and an electric field perpendicular to it, then a Hall current is generated since the ions have ...
480 views

Semiconductors vs. Metals Conductivity at High Temperatures

For metals, I've been told that as temperature increases it's resistance increases, due to the lattice vibrating more, and thus there are more collisions with electrons (increasing resistance). ...
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Interference in electron conductance through e.g. single molecule or semiconductor?

Imagine attaching electrodes to a complex sample, e.g. a semi-conductor or a single chemical molecule, leading to some electric current. Can we decompose this electron flow into local flows? - like ...
218 views

Why aren't all insulators transparent, since they have a large band gap?

According to Floris' answer in this link, diamonds are transparent as they have large band gaps while graphite is black as it is a conductor. As electrical insulators generally have a large band gap, ...
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How do excess charges move in an insulator?

I am currently studying intro into electrostatics and reading my notes from teacher that stated, "an insulator holds on tightly to its outer electrons and does not permit the flow of electric charges ...
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Why $d^{10}$ metals follow the free electron approx better than the other metals

The free electron gas model is surprisingly good at explaining the properties of the conduction electrons in metals, but it works better in some metals than others. In particular it works well for Au, ...
613 views

Tap water conductivity differences between AC and DC

Direct current is often used in electrolysis and because of the alternating nature of AC, it's not great for electrolysis. Tap water, however, conducts AC really well. But why is that? Why does ...
686 views

Is it a magnetic or an electric field that causes induction in the antenna?

wiki says that: The electric field (E, green arrows) of the incoming wave pushes the electrons in the rods back and forth, charging the ends alternately positive (+) and negative (−). but ...
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Determination of electrons flow through the crystal

Talking about doped semiconductors: Atoms outer shell extends and overlaps with another ones outer shell (the conduction band), right? So when electrical field is applied to a semiconductor bar (lets ...
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Difference in conduction in metals and semiconductors

According to Fermi-Dirac statistics, in a metal, only certain number of valence electrons take part in conduction when they acquire an energy equivalent to KT for some temperature. Now my questions ...
647 views

How to calculate the Electric field near a 2-D charged square sheet of conducting material with finite area?

The case for infinite sheets are simple enough, and also for a disk of finite size, which can be derived as in the picture. title edited to specify sheet is finite.
962 views

What happens to metal when exposed to an electric current for an extended period of time?

I was wondering what happens to the actual metal (copper, aluminum, silver, gold) when electricity is ran through it for a long period of time. Say years like the wire in a house. Does the ...
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Are covalent crystal compounds with lone electron pairs electrically conductive?

In molecular compounds valence electrons can pair up and satisfy each other such as with carbon where the electron configuration is like the following but each electron is paired up with another ...
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Regarding the zero internal electric field in a conductor (electrostatic case)

Let's say we have a homogenous electric field in the $z$-direction. For computational simplicity let's say we have a thin sheet of metal covering entire the $x$-$y$ plane. The answer here is straight ...
480 views

Why does AC Conductivty in Drude Theory have an Imaginary and a Real Part?

In the Drude Model the direct current (DC) conductivity is given by the following formula: $$\sigma_0=\frac{ne^2 \tau}{m}$$ where $\tau$ is the relaxation time. Furthermore, the AC conductivity in ...
397 views

salt water conductivity

my book says the following on conductivity in water with ions. I am confused about why electrons from the zinc (anode) repel positive ions. Because zinc becomes negative, shouldn't it attract it? ...