Conductivity Definition and 382 Threads

if ∧m = ∧mo - A√c then till where is this formula ∧m = κ/c applicable because if for infinite dilution c = 0 it gives molar conductivity infinite. Please explain how conductivity and molar conductivity varies with concentration of electrolyte.

How does insulator's density affect its thermal conductivity? For example, considering such insulators as rock wool, It seems that the thermal conductivity should increase with an increase in density (due to elimination of 'air pockets'). However, experimental results, in many cases, look more...

Hi, I need to conduct experiments at fixed pH. The complication is that the solution I'm using will have NaCl in it. So if I add HCl or NaOH to make the solution more acidic or basic, the conductivity of the solution (as measured by a conductivity meter) will change due to the added Na+ or Cl-...

Hello friends, I am having a hard time understanding thermal conduction and was hoping someone could shed some light for me. I am looking to protect a component from heat by placing a thermal barrier between it and the heat source, the heat applied to the surface of this barrier would be...

I have a question that I've been debating with some co-workers. We are using conical springs (tapered) that most of the time in our application fully compress once engaged. We are measuring minute changes in temperature and I was wondering if a spring diffuses more heat compressed or relaxed...

ZrO2 is an ionic conductor used in automobile engine control systems. At 800oC the mobility of Zr4+ is 0.01m2/V.sec, and of O2- it is 0.04 m2/V.sec., there are 4.5 x 1017 mobile Zr4+ ions/m3, and 2.0 x 1018 mobile O2- ions/m3. What is the conductivity of ZrO2 at this temperature, in S.m-1...

Hey there. I am making Carbon pellets using polyvinyl alcohol as a binder to help shape the pellets. I would like to measure the pellet's conductivity without being hindered or influence by the conductivity of the PVA. One way to do it is to heat the pellets to 300 degrees and evaporate the PVA...

Homework Statement The following questions apply to a confined groundwater aquifer consists of a homogeneous sandy soil with hydraulic conductivity, K, of 3 x10-2cm/sec. In the area of interest, the hydraulic head is 500 m, the aquifer length is 10 km, and the cross-sectional area of the...

Hey! I'm currently solving the heat equation using finite differences. I have a conductivity k(u) that varies greatly with temperature. It even drops to zero at u=0. I have discretized the equations the following way: \frac{\partial}{\partial x}\left( k(u) \frac{\partial u}{\partial x}\right) =...

How to calculate K or Q without one or the other? For example, if the material is unknown (but cannot test density, or melting temperature) how would you test heat flux? Q=K(Th-Tc)/(x)

Homework Statement After performing a lab experiment to determine the conductivity if Pasco conductivity paper, I found the conductivity to be 0.195 Ωm. We found conductivity by graphing measured values of voltage (y axis) and the length (x axis) between the probes of a voltmeter that are...

Hello everybody, I'm new. It's a long time a have a big (probably stupid) doubt about the interaction between light and media, and now it's time to solve it. The doubt its essentially concerning the difference between an antenna and a photodetector: the first one is able to detect the amplitude...

Why doesn't SiCl4 conduct electricity when it's in its molten state and conducts electricity when water is added? The answer is C. I know very well what is X and Z, but unsure what is Y.. Why not Al2O3? What's the difference? Does it got to do with their structures? Al2O3 is ionic with a degree...

I have studied that Ions conduct electricity in solutions due to their ability to move freely.BUT EVEN THE WATER MOLECULES MOVE FREELY, but they don't conduct electricity.What's so special in ions? I have studied the entire electrolysis process , in which the ions are attracted to the...

Hi! I am currently trying to determine how the salinity ##S## of a sample of seawater (or, objectively, a salt-water solution) changes its electrical conductivity ##\sigma##. It is clear that they are proportional since the mobility of the ##\text{Na}^{+}## and ##\text{Cl}^{-}## ions plays a...

I was reading about semiconductor transparent conducting oxides and I found this why p-type conductivity is limited in TCOs. But I could not understand its meaning please someone explain me how the holes are localized at valance band edge and how dominated by oxygen- 2p levels? ''Owing to the...

whats the thermal conductivity for car insulation? roof or dashboard, basically the thermal conductivity of foam used in most cars.

Let's say you have a small metal case that is 3 inches by 3 inches versus 2 inches by 2 inches. Inside at center is a heat generating source (let's say a small processor chip). How efficient is the transfer of heat from the processor to the air... and from air to metal between the 2 different...

If you rub two electrically neutral pieces of insulation together, one piece becomes charged and the other piece becomes oppositely charged. Does this transfer of electron depend merely on the electron affinities of the two pieces, or does the conductivity of the two insulations play a part? I...

Hi all, I am not sure if the is the right place to post the question being new to the forum, but I am looking for some help with a heat transfer experiment that I ran for my honours thesis. Essentially the aim is to determine if warmed saline fluid bags taped to 3 different types of tree barks...

So, there's a project I'm working on (no, it's not school related), where I'm trying to figure out how to measure thermal conductivity of a material using laminar flow. The idea is to integrate this into a larger system, and it's a measurement I'd like to take in the process. I know the...

Since the flow of heat in solids happens due to the collision of the molecules with each other, thereby increasing their internal energy, a higher denser material will have molecules closer, does it mean that the thermal conductivity of high density materials will be higher than the lower...

Copper ::: 60.7 x 106 S m^-1 Silver :::62.9 x 106 S m^-1 Gold :: 48.8 x 106 S m^-1 Why is the electrical Conductivity of these elements this way? I mean down the periodic table it should increase in case of GOLD but instead Gold is have far less value of Electrical Conductivity.

Hello my name is Mike Moore and I work for Copperhead Industries, LLC We are a tracer wire manufacture for the underground non-metallic pipe utility sector, natural gas, water, sewer and telecom. We use magnesium anodes for grounding out the far end of the tracer wire system which completes...

Aluminium surfaces are protected by a thin aluminium oxide layer. The oxide layer supposedly does not conduct electricity. However, when measuring the contact resistance between the test pen of a multimeter and the aluminium, this resistance is always small. Why? Is the oxide layer easily punctured?

why resistivity of a metal increases with increase of temperature and conductivity of a semiconductor increases with increase in temperature??

Homework Statement Two plane parallel electrodes are separated by a plate of thickness s whose conductivity \sigma varies linearly from \sigma_0 near the positive plate to \sigma_0 + a near the negative plate. Calculate the space charge density \rho_f when the current density is J_f ...

Homework Statement Show that the minimum conductivity of a semiconductor occurs when n0 = ni√(μh/μe) Derive an equation for the minimum conductivity Calculate the (i) minimum and (ii) intrinsic conductivity for silicon. State the assumptions you make and the origin of any material properties...

I have measured the conductivity of a 2D material. I want to use σ=N⋅e⋅μ to find the mobility μ=σ/(N⋅e). https://en.wikipedia.org/wiki/Electron_mobility#Relation_to_conductivity I have measured N using a spectroscopic/imaging technique to get a Surface Density with units [cm^-2]. Mobility...

what happen to the conductor if it reaches the critical temperature where high conductivity and then back to the original case does it preserve by an amount of high conductivity or high conductivity disappear just a question I'm engineering student electrical power department

Using kinetic theory, we can derive an expression for the thermal conductivity of a gas to be κ=nCmoleculeλ<v>/3 where n is the number density of the molecules in the gas, Cmolecule is the heat capacity of a single molcule (i.e the heat that must be given to each molecule to raise the...

Homework Statement Suppose the conductivity of the material separating two coaxial cylinders, of radius a and b (a < b) and held at a potential difference ##V##, would not be uniform. Specifically, ##\sigma(s) = k/s##, for some constant ##k##. Find the resistance between the cylinders. [Hint...

Hi I've made what I think is graphene. I first put the solution on cardboard and then I put some on polyethylene. When they had dried, I tested conductivity with a digital multimeter with the scale set on megaohms. The cardboard was nonconducting, but the sample on poly to my astonishment showed...

Hello, I am curious why in the resistivity formula you divide the length by the area? R=P*(L/A). I cannot figure why you would not take the L*A to get volume?

1) PROBLEM: Task is to find the thermal conductivity of steel experimentally. I have conducted relevant experiments and I am trying to solve for the thermal conductivity (k) itself. My final however is ten times too large in size, and I am having trouble identifying where the error is coming...

Homework Statement The temperature within the Earth's crust increases about 1.0 C∘ for each 30 m of depth. The thermal conductivity of the crust is 0.80 W/C∘⋅m. A)Determine the heat transferred from the interior to the surface for the entire Earth in 9.0h . B)Compare this heat to the amount of...

The thermal conductivity of most solids and liquids decreases with increasing temperature, but water is an anomaly because it actually increases with increasing temperature. I don't understand why though. I suppose it is something about the material itself and its hydrogen bonding, but not sure...

The information I am given is : a door has two steel layers both are .47 mm thick, the door itself is 725 mm by 1800mm. The question asks, how thick of a layer of wood (oak) would have to be put in the door to limit the heat loss to 740kJ per hour? Temp inside is 18C and outside is -20C All...

Homework Statement One end of an insulated metal rod is maintained at 100∘C and the other end is maintained at 0.00 ∘C by an ice–water mixture. The rod has a length of 60.0cm and a cross-sectional area of 1.40cm2 . The heat conducted by the rod melts a mass of 7.15g of ice in a time of 15.0min...

Homework Statement Determine the thermal conductivity of a metal (assume linear heat distribution at steady-state, and well insulated), given, Thot = 96.8 Tcold = 29.5 There is also: 13.7 W being pumped in at one end. Water convecting heat away on the other end. Homework Equations...

Hi everyone, i am trying to solve and program a non linear differential equation in MATLAB where thermal conductivity depends on temparature.I am trying it to solve by explicit finite difference method. the given equation is ∂2t/∂x2+∂2t/∂y2 *k(t)= -q (x,y) i have solved the equation taking...

Hi, I got the complex conductivity vs. frequency table of a metamaterial. Its first lines are like this: f conductivity 1GHz 0.004+0.00297i 1.1GHz 0.004+0.00295i 1.2GHz 0.003+0.00294i the table goes up to 10GHz. Now the problem is that I need to enter...

Is there any such material which can be made to conduct from a non conducting state by external means like shining a light or any other EM wavelenght on it or other means , that could alter the material ohmic resistance to electric current

I've known that the conductivity of semiconductors increase with temperature because more electrons are freed, But why doesn't the scattering and vibrations of the lattice affect the conductivity in semiconductors as in metals?

(Heads-up: these might be QM questions) Two questions: 1.) What is it that gives rise to the fact that conductive metals provide a much lower potential for electrons to exist, than in free space? 2.) If conduction in wires take place due to an E-field that "travels" through/along...

Homework Statement If a copper kettle has a base of thickness 2.0mm and an area 3.0 x 10-2 m2 estimate the steady difference in temperature between the inner and outer surface of the base which must be maintained to enable enough heat too pass through so that the temperature of 1 kg of...

Hello. Electrical conductivity is written as \frac{n_{e}e^{2}}{m_{e}\nu_{ei}} where n_{e}, e, m_{e} and \nu_{ei} are for electron density, charge, mass and electron-ion collision frequency. According to Wikipedea, http://en.wikipedia.org/wiki/Electrical_resistivity_and_conductivity Unit...

Hello. In CGS unit electron thermal conductivity for plasma is expressed as \frac{n_{e}T_{e}}{m_{e}\upsilon_{e}}\Gamma_{1} [1] where \Gamma_{1} is the dimensionless transport coefficient. [2] You can also find similar expression in...

Calling kinetics experts: rate law from conductivity isn't possible!? Consider the usual primary halogenoalkane aqueous alkaline hydrolysis reaction RX + OH- --> ROH + X- We know the rate law is first order in RX and OH-. We could separately represent the drop in OH- conductivity as an...

Homework Statement Part (a): Derive Clausius-Clapeyron Equation. Find latent heat of fusion of ice. Part (b): Find rate of formation of ice Part (c): What is the maximum thickness of ice formed? Homework Equations The Attempt at a Solution Part (a) I have derived the...