Conductivity Definition and 382 Threads

For my advanced higher physics investigation I've been given the topic of thermal conductivity. Basically I am going to investigate the thermal conductivity of different metals and compare them to the electrical resistance of the metal as I believe that those with low electrical resistance...

Homework Statement Solid cylindrical copper rod 0.2m long has one end maintained at temperature 20K, other end blackened and exposed to thermal radiation from surrounding walls at 500K. As the rod is insulated, no energy is lost or gained except at the ends of the rod. When equilibrium is...

Does the k value have any relationship with the temperature of the wall (use of the word wall becuase that is what the k value is mostly used with).

Hello, Assume that we have a pipe flowing with air of around 80 degrees F surrounded by air of approximately 140 degrees F. The pipe can be made out of three materials: Aluminum, Mild-Steel, and Stainless Steel. What material would it be best to use for the pipe in order for the air flowing...

I had the following question on a Physics Quiz and I am wondering why the answer is D. When you walk barefoot in a room, the floor feels cooler walking on a tile floor as compared to a wooden floor because A) tile has a smaller specific heat than wood. B) tile has a larger specific...

The following data shows the conductivity of 5 metals and the rate of change in gravitational potential energy due to induced current when the metal is passed through a electromagnetic field of 5.4mT on the end of a pendulum. you know, the classic eddy current experiment. I'm just wondering if...

The conductivity of pure germanium increases by 50% when the temperature is increased from 20 degree C to 30 degree C. What is the energy gap E_g between the conduction and the valence bands of germanium? b) For silicon E_g = 1.1eV, what is the percentage change in the conductivity for the...

Hi Everyone, This is my first post here, so have mercy on me :redface: Project: Using a Non-Contact Probe (Sensor) To detect an unknown 1"x1" cube's (it can be steel, alumnium and plastic) Electrical Conductivity (EC) and hence decide its material. Measurement of EC must be in levels of HI...

Hi Zz. I know that this is one of your specialties so here it is. I have a question that is bugging me. Using Bohr's Atom as a model for the Question. The difference in electrical conductivity between pure Gases Neon and Condensed pure Solid Neon (frozen), is there a difference in...

1) I'm in need of some values (tables) about heat resistance, conductivity, and such for different types of building materials. Any good sites out there? 2) I have the following equation for calculating Grashofs number: Gr = g \cdot \beta \cdot \Delta t \cdot {{l^3 } \over {v^2 }}...

In all the source I have read about, EM field analysis of Transmission Lines always assume the conductor is perfect (infinite conductivity), and that simplify a lot the analysis, since there can be no field inside the conductor and that gives much easier boundary condition, which allows us to...

In this problem you will estimate the heat lost by a typical house, assuming that the temperature inside is 20 degrees and the temperature outside is 0 degress . The walls and uppermost ceiling of a typical house are supported by 2*6-inch wooden beams with fiberglass insulation in between. The...

Someone once told me that almost all alloys have poorer thermal properties then their component metals. Is this true? I want to have a little experiment but I don't want to do it if I know all the results will be crap.

Is there any direct relationship between these 2 properties of a matter?

Does anyone know how we feel heat when we touch? I ask because I wonder if two different objects of the same temperature will "feel" different to humans simply because of their different heat conductivity. For example if you touch two things that are both at 0 deg C, one is a block of iron and...

Hi Can someone help me with the following questions? 1. How does temperature affect the # of charge carriers in a semiconductor? Explain 2. The # of ______ electrons is equal to the # of electrons available for conduction. Why? 3. How do dislocations affect the mobility of electrons in...

A cylinder with a piston is filled with ideal gas. The gas temperature is held at 500K. The cylinder is heated by an oven through a square metal rod connected between the oven and the cylinder. The rod has sides 2.5cm and length 2m. (a) If the oven is held at 1300K, and the heat current...

Hello. I just wanted to know if a material in the LIQUID state has a higher thermal conductivity than the same material in the SOLID state. I am thinking specifically about the metals, but I suppose it should be the same for non-metals (or not?).

Hi everyone :) please I need help to show me what to do with these points related to the conductivity of solutions experiment : 1- results I got from this experiment are the acid in mol dm and the conductance in mS. however, how can I get the aci in mol m,square root of the acid in...

Does "pure" i.e. distilled water conduct any electricity? I thought that the answer was no...that the conductivity of water was a result of impurities. But I became confused by post # 3 here: https://www.physicsforums.com/showthread.php?t=64920 which explains that it has something to do...

Hi, I'm stuck on this problem: Two solid hemispherical conducting electrodes each of radius r=a are pressed into the earth, curved surfaces down, such that the flat surfaces are flush with the (flat) Earth's surface. Assume that the electrode separation (center to center) is d where d >> a...

Hi there,...this isn't homework..its more to my practical...anyways...from the attachment given..that is the first page of my practical guide...the problem is...on the procedure part...it asked me to plot a graph of lg temp againts t ...if i do so...how do i get the thermal conductivity of glass...

Hello, This is a homework problem for my Introductory Physics(no calculus) class but it's relatively simple so I opted to put it under high school. First I'll state the problem then my thoughts. A copper rod (k = 390) has a length of 1.5 m and a cross-sectional area of 4.00*10^-4 m^2...

How do you with a simple model explain the temperature dependence of the electrical conductivity. If you use the Drude model you get for the electrical conductivity sigma = ne^2t / m where n is the density of mobile electrons and t is the relaxation time. t is the time between...

Hi, i would appreciate any help i could get on this, thanks. I'm stuck on part of a biomechanics assignment which is to work out the thermal conductivity of neoprene. I've done this part but am having difficulty on the following question; "Using the value that you have obtained for thermal...

I need a simple method of measuring thermal conductivity of liquids for a school project. I have access to the school's science labs, so I can get the basic equipments (hopefully). All I need is a method of measuring thermal conductivity.

Please Help! Thermal Conductivity :eek: Hi. I need help with the thermal conductivity units. I took the slope of a Natural log(temperature change) Vs. Time graph ( degrees Celsius/unit time) and I need a conversion to Watts per Meter Celsius. If anyone could help that would be great since I...

A tank holds water at 60 degrees C. The outside temp. is 10. The thickness of the walls is 12mm. My goal is to find the temp on the wall on the outside of the tank. I've got some values I don't know the english name for, but hopefully you'll understand by the units. \lambda for steel is...

I have been examining literature related to charge redistribution at the Earth's surface and I found an application that treats the Earth as a near perfect conductor. http://tdworld.com/ar/power_one_wire_enough/ www.stonepower.se/Images/SWER.pdf The articles in the above URLs are...

Conductivity, altered by a magnetic field? Hi Im a high school student studying physics. I conducted an experiment that measured the conductivity of KCl electrolytic solution vs. a change in concentration. Anyway, i had a magnetic stirrer stirring the solution in a beaker when the...

Hiya! The thermal conductivity al Al is twice that of brass. Two rods (1 Al and the other brass) are joined together end to end in excellent thermal contact. The rods are of equal lengths and radii. The free end of the brass rod is maintained at 0 degrees C and the Al free end is heated to...

Hi... there is a question i can't figure out. "A 400-g stainless steel tea kettle containing 500g of water is on top of the stove.The portion of the tea kettle that is in contact with the heating element has an area of 0.005m^2 and is 2.5mm thick. At a certain moment,the temperature of the...