Conductivity Definition and 382 Threads

Hello! Does anyone have an idea of how can I obtain information from a band diagram about the directions along which the system conducts best and worst ? Thank you in advanced! :)

Progress This is the experimental data of thermal conductivity of stainless steel 304L at low temperature. The data is calculated with the Fourier's law of thermal conduction. I checked many times in the excel file and I confirmed that there is no mistake in the calculation. The parameters are...

Hi, I am reading "An Introduction of Solid State Physics" from Ibach Lüth and don't understand the integration process. They write $$\sigma=\frac{e^2}{8\pi^3 \hbar} \int df_{E}dE \frac{v^2_x(\bf{k})}{v(\bf{k})} \tau(\bf{k}) \delta(E-E_F) $$ $$ = \int_{E=E_F}^{}df_{E}...

Hello, I have four questions. As it stands now, I don't have the necessary materials to test this myself, which is how I'd prefer to learn the answer. I still plan on doing this experiment for fun once I can acquire the necessary components. This deals with Lenz's Law. My goal is to maximize...

Dear friends, does anyone know if there exists any study about electrical conductivity of liquid argon? Thank you in advance for any suggestion.

Homework Statement I need to calculate the specific conductivity k and the resistance R of a cell containitng 0.01 M HCl and 0.1 M acetic acid (HAc). I know the molar conductivity of HAc: Λm = k/c = 5.14 cm2S/mol. I also know Ka (HAc) = 1.795 *10-5. I know the cell constant Kcell = R*k =...

<< Thread moved from a technical forum, so no HH Template is shown >> Our teacher gave us a lab, and we have to write a procedure on how to test the electrical conductivity of multiple substances. However, on the materials, all that was written was "electrical conductivity tester", which I'm...

Hi, If some voltage is traveling from a low conductivity metal to a high conductivity metal, does it impose limitations on the high conductivity metal such that it will only do as much as the low conductivity metal?

Homework Statement The question below is asking how long it would take for the cooler side of the handle to heat up till its unbearably hot. I'm having a bit of trouble trying to understand the solution and would like some guidance. I can't seem to get how the ##\Delta T ## that represents...

Maybe someone can help me out; I've been seeing conflicting information on the meaning behind optical conductivity vs AC conductivity. Some papers seem to post plots of transmission and reflectivity, and others a Drude-like \sigma(\omega). In many textbooks I can't seem to find a satisfactory...

Homework Statement Hi there, I am designing a heat exchanger and I am really struggling to find out how to fairly accurately estimate the density, viscosity and thermal conductivity of a gaseous mixture at ~~20bar. There is 8 components in the mixture: methane, ethane, ethene, ethlyene oxide...

Question#1 I would like to compare a 100' length of 4" PVC pipe with air in it surrounded by Earth and/or water. What length of 4" copper pipe would equal a 100' length of PVC? Question#2 If the inside of the pipe had turbulence what length of non-turbulent 100' PVC 4" pipe would it equal? I...

I know that electric conductivity of metallic conductors increases with decrease in its absolute temperature(kelvin) . But is it the same for electrolytes such as water. Is cold water a better or worse conductor of electricity than warm water at same pressure and concentration.

Homework Statement I have some data from measuring EC in solutions and I don't know how to convert EC to pH Homework EquationsThe Attempt at a Solution I use Arduino for programing. Values of ADC of EC that I collect from microcontroller are 80 ( for EC : 0.2mS/cm ) , 90 ( for EC ...

Homework Statement Homework EquationsThe Attempt at a Solution Part 1.1) I managed to find the energy needed to melt the ice, before using ΔU = Nf½KΔT to solve for the new temperature, which was correct Part 1.2) Initially tried using ΔQ = mcΔT before realising that I didn't have the mass...

Greetings Denizens!, I'm building a small "zapper" for the purpose of keeping critters away from a deer feeder. Other than volts and amps ratings, I believe it is, for all intents and purposes an electric fence, just in a unique configuration (shape, not electrical specs - those are within the...

Hi Dear, First of all I thank the administrators and the whole team that runs this forum for having accepted me to be part of this great family and also for the quality of this forum. So, I have a question regarding conductivity which is an inherent property of material, Currently I take a...

I have found a lot of data and graphs showing conductivity (micro-mhos) vs % by weight of various salt solutions. The salts for which graphs appear particularly linear are those of alkali Earth metals - eg sodium, potassium - KI, KBr, KCl etc. Is there a theoretical equation for conductivity vs...

Hi, Quick description of the problem at hand: spherical perfect conductor around the origin with radius a, spherical shell (with radius b) around it made of a material with given magnetic permeability bigger than 1. Uniform Magnetic field in the area. The solution I am looking at (which I won't...

according to the definition given to me by my book conductivity is the conductance of one unit volume of an electrolyte. on the other hand molar conductivity is the conductivity of one mole electrolytic solution. so what's the difference and how should I relate these 2 terms? will two solutions...

I am trying to derive the DC electrical conductivity using the pertubation theory in Interaction picture and linear response theory. If working in a energy eigen basis and using the density matrix, the Fourier transform of the susceptibility can be written as ##\chi {(\omega )_{ij}} =...

Hello, I would like to ask if I have this data from impedance spectroscopy: frequency, Z(im), Z(Real), how should I calculate conductivity ? Should I use R(im) or R(re)?

Homework Statement why there's no horizontal conductivity in this question ? Homework EquationsThe Attempt at a Solution IMO , there's also horizontal conducitivity in this question because of the water can also flow horizontally across layer A , B and also C . [/B]

I was solving the problems given by Griffith in his book 'Introduction to Electrodynamics' and stumbled across this question. "Because sigma (conductivity of the medium) is a function of position, the equation 7.5 does not hold" --i get this point; current density isn't constant and so its...

More thermal conductivity means there's more energy?...

Aluminum metal covers itself immediately of an oxide layer in air. This layer is quite thick, more than 0,01mm they say and it's non-conductive. This layer infact is, e.g., thick enough to prevent soldering, further chemical attack by air oxygen or water (with which nude Al would immediately...

Hi all, I'm working through chapter 2 of Michael Tinkham's Introduction to Superconductivity. On page 40, he asserts that the skin-depth for a general complex conductivity is (In Gaussian units) $$\delta = \frac{c}{\sqrt{2\pi\omega\left(|\sigma| + \sigma_2\right)}}$$ where $$\sigma = \sigma_1...

First up, what is the prefix thing about? I picked "B" but I have no idea whether this is correct. My question is pretty simple. How does an electrolyte conduct charge below the potential threshold of any redox reactions (ie the threshold for electron transfer)? Is it purely due to EDLE? If...

Hello, could you help me please about how can I calculate dielectric constant form electrical conductivity?

Homework Statement A long round wire of radius a and conductivity σ is coated with a material of conductivity 0.1σ. (a) What must be the thickness of the coating so that the resistance per unit length of the uncoated wire is reduced by 50%? 2. Homework Equations [/B] R = l/(σS) where R is the...

Homework Statement The problem is given. Homework EquationsThe Attempt at a Solution I tried to solve the question as if there is a nanowire between two reservoirs and got an answer. But I don't know what should I do to measure thermal conductivity in a thin film. My formula for k in a...

Suppose I have a tank which is made of steel coated with a thin layer of glass on the inside to protect the steel from corrosion (the material stored inside the tank is corrossive; say for arguments sake Water with 10% Hydochloric Acid). In theory, till the glass is intact there is an...

graphite has high conductivity , so i though of making a touch button out of a pencil drawn pattern on the wall.the pattern is shown below. when not touched -resistance between ends of the pattern >200Mohm (exceeds dmm limit) when fully pressed - resistance between ends of the pattern = 1.3...

Is there an easy way to calculate the temperature on one side of a material if we know what material it is, the thickness of it and the temperature on the other side. Basically can we calculated the heat transferred through a material if heated. Thank you

Hi folks, I purchased two books on electric transport at the nanoscale and unfortunately I just found theoretical models and formalism... but the actual data from the experiments was not there. So I am curious about it, I am looking for information on nanowires, quantum dots etc and I would...

Hi Guys I was studying the thermal properties of SiC at high temperatures and now i have a few questions Usually, at high temperatures, the photons effect are much more intense than phonons at high temperature, correct? According to Rosseland heat diffusion equation Krad = 16σT3 /3β, β= 4πK/λ, σ...

my research is about "The effectiveness of different basic substances on the Eletrical conductivity" and i need " significance of the study " 1) who are the beneficiaries and what benefits will they get ?Please help I am a high school student struggling with my research

My partner and i have been running experiments for our research in micro algae separation, using a reactor containing aluminum electrodes. we run a 10v current across the electrodes, and flow saltwater between them. we were wondering how changing the conductivity of the saltwater might affect...

Are metals better conductors in the presence of visible light? Considering photons in visible spectrum are not energetic enough to induce emission from a metal surface but they do cause the ejection of 'conduction electrons' which are bound to the metal by a few electron volts.

Hi everbody My plots seem to show that conductivity between two nails immersed a few mm in tap water falls off at low voltages instead of being a horizontal flat line as would be the case for a linear ohmic medium. And the deeper the immersion, the less linear the conductivity. Is this normal...

This snapshot is from the book Solid State Physics by Ashcroft,Mermin. They represented the Field and Momentum as the real part of a complex function. As far as what I understand, we represent fields in complex notations for our own convenience over the standard real representation which results...

See ref (Smits, 1958, Bell Technical Journal: http://onlinelibrary.wiley.com/doi/10.1002/j.1538-7305.1958.tb03883.x/abstract (also Google will show a pdf copy that is not pay-walled) The paper describes correction factors for doing 4 probe conductivity measurements on cylinders (semiconductor...

Homework Statement My textbook on lasers has mentioned thermal conductivity a few times, but hasn't specifically mentioned it's importance. I'm at a part talking about Nd:Glass lasers and it says that glass has a lower thermal conductivity than Nd:YAG lasers, which prohibits continuous wave...

I'm designing an oven and want to ensure that the insulation I specify has a low enough Thermal Conductivity (k) to resist excessive heat loss. I determine heat loss (Hout)with the following equation: Hout=A*U*(T1-T0). U is dependent on k (U=k/L). I omitted the heat transfer coefficient in...

If I have a certain circuit set up with a voltage V, then how does increased conductivity in the wire affect the voltage, or does it? I know that increased conductivity affects current, but if Ohm's law is to be true , voltage must increase or resistance must decrease. So which is it? Is voltage...

Homework Statement I would like to derive an equation that relates the thermal conductivity to the pressure using the kinetic theory of gases. However, I assumed that thermal conductivity was independent of pressure. Homework Equations I know that P = 2N/3V (1/2mv^2) Also: I believe that...

I am trying to create a conductive Silicon Carbide (SiC) heating element. The US patent 650234 "Process of making carborundum articles", filed in 1899 states essentially that crushed SiC crystals can be be glued together (using diluted glue) then sintered. It states that the addition of 15-20%...

Sphere of mass m, and charge q is hanged on a thread of length l in a constant gravitational field g. There is infinite horizontal conductive plan which is kept at potential 0. Find period of small oscillations of sphere. So my question is next, how do i get the force due tu charge q in Newtons...

Hi I am new to the forum, I am using darcy's equation to model a tumor - tissue medium. In the literature I found that K - Hydraulic conductivity is given by cm^2/(mmHg.s) But in comsol it's given by (m/s) Is there another term involved in this?

For example can an object be very conductive to electricity but be a very poor conductor of heat and vise-versa, or is a good conductor of one always a good conductor of the other and a bad conductor of one always a bad conductor of both? If they are related, then how and why are they connected...