Resistivity Definition and 189 Threads

Homework Statement A wire has a diameter of 1.51 mm and a length of 32.7 m, and is found to have a resistance of 1.5 capital omega. What is the resistivity of the wire? Homework Equations The Attempt at a Solution R=qL/A R=.0051/2=7.55E-4 L=32.7 A = ? How do i find A to...

I am revising for my A levels and I have noticed that a common question on the paper is to define RESISTIVITY. I have looked and looked but found no definitive description or a good definition. I know the formula but is it right to just say that "resistivity is directly proportional to a...

What is the difference between resistance and resistivity ?? I have studied that the electric resistance is directly proportional to length of material and inversely proportional to area of cross section . In this resistivity becomes constant and determines conductivity by sign "rho" . What is...

Homework Statement A cylindrical conductor of length l, diameter D and resistivity ρ has resistance R. A different cylindrical conductor of resistivity 2ρ, length 2l and diameter 2D has a resistance A. 2R. B. R. C. R/2. D. R/4 Homework Equations I assume its R = pL/A The...

Does anyone knows the resistivity of Ringer's solution?

Hello fellow physics-people, I was just thinking about the following setup: We have a conducting surface (with smoothly varying resistivity) hooked up to some battery with the wires contacting the surface at two arbitrary points, A and B. How would we go about figuring out the current...

Homework Statement http://img710.imageshack.us/i/2631001.jpg/ #29 Homework Equations p=I^2R P=IV The Attempt at a Solution well, the answer is D, but i don't see why the length matters? can anyone find out the equation for this problem? i thought it was B) cable B because it has...

I think what I am doing is pertaining to ohms law but I'm not sure because we're not suppose to rely on equations or literal physics terms, but when we learned from previous labs. So this is mostly conceptual and I want to make sure I'm thinking through this correctly. Diagram 1...

Sorry everyone, I forgot to post my efforts in solving the problem, so here I go again: The question says: Suppose you wish to fabricate a uniform wire out of 1.00 g of copper. If the wire is to have a resistance of R=0.500 Ohm, and a density of d=8920 kg/m3, and if all the copper is to be...

Homework Statement a 15ft length wire with a cross sectional area of 127 c mils has a resistivities of 8.74 ohms at 20 C. What material is wire made of. Any help would be appreciated. (pi/4*10^-6) was given by the book. Whats odd is when I enter pi/4*10^6 instead for wolfram I'm getting the...

The equation of linear thermal expansion is l=l_0\left[1 + \alpha(t - t_0)\right] (it is similar also to the equation of resistivity, \rho=\rho_0\left[1 + \alpha(t - t_0)\right]) \alpha is a constant dependent only on the material we are speaking about. Now, let's say I have a bar 100 m long...

Homework Statement A cylinder of radius a with a hole through it (of radius a/2) is filled with a material of resistivity p_2. Show that the total resistivity is now 4*(pL / pi*a²) (p_2 / 3p_2 + p) Homework Equations R=pL/A The Attempt at a Solution I started with a full cylinder...

What is the meaning of zero resistivity in superconductors? I mean, what's the cause of zero resistivity in superconductors?

Homework Statement A block of carbon is 3cm long and has a square cross section whose sides are .5cm long. A potential difference of 8.4V maintained across its length. a)What is the resistance of the block? b)What is the current in this resistor? Homework Equations R=pL/A where p is...

Homework Statement I'm just trying to understand what the variables in this equation represent. This is part of a study of electrical resistivity lab that I am doing. I don't have my Kittel book with me, and the lab manual for some reason doesn't define these variables. Homework Equations...

1. A standard 100 W (120 V) lightbulb contains a 8.50 cm-long tungsten filament. The high-temperature resistivity of tungsten is 9.0*10^{ - 7} ohm*m. What is the diameter of the filament? 2. p= resistivity, E = V/L, I = AV/pL, R = pL/A... 3. I know that I'm going to solve for A =...

So, resistivity goes like \rho = R \frac{A}{l} (where A = cross sectional area, l = length) I solved for resistance and got R = \rho \frac{l}{A} If R = \rho \frac{l}{A} = \frac{V}{I} would the current correspond to the ampacity of the material? Or, if you were to replace R in the first...

Homework Statement The conductance G of a device is defined to be the inverse of its resistance, G=1/R. What is the conductance of a device through which the current is 2 A when a potential difference of 60 V is applied? Homework Equations R= V/I R= (resistivity)X (length)/Area The...

My only problem with a basic conceptual understanding of the Quantum Hall Effect is the relation between longitudinal conductivity and resistivity when the magnetic field is such that the filling factor is an integer, and the Hall resistance is quantized. I fully understand the splitting of the...

Hi I was wondering why high end audio equipment is plated with gold when copper is obviously cheaper and has a lower resistivity. Anyone shed any light on this? Thanks Paul

This is a suggested relationship between L/R and L L/R = kl + A/P P is the resistivity, A is the cross-sectional area and k is the constant for the circuit Using the value of the y-intercept find a value for P with the appropriate unit The graph of L/R against L had the intercept of...

Homework Statement This question is about the heated front windscreen of a car The heater consists of resistance wires which are embedded in the glass A) The power of the heater needs to be 180W for a satisfactory demisting A car battery of Negligable internal resistance supplies 12V to...

hi I am new member of this forum..Plz tell me how to use this forum & how to ask Question from other members...Plz tell me differences b/w emf & voltage,Resistance & resistivity..

I was doing some questions from a book on resistivity and I came across this, I really can't work this out, I'm stumped.

I am working on a Project that involves determination of Quality of Steam. In that I have few queries, so please help if possible: 1. Is there any mathematical relationship between Resistivity of water and temperature? because i am not able to find one, but since i am working on this...

Hello everyone. This question may sound naive, but since I am relatively new to the subject, I would like to ask for some clarification related to phonon and electrical resistivity. As most of you might be aware of, electrical resistivity of crystalline metals increases due to increase in...

Hi all Is zero thermal resistivity equal to having infinite thermal conductivity?

I am just wondering if pure carbon and graphite have the same resistivity? Resistivity for pure carbon = 3.5 x 10^-3Ωm:frown:

What is the difference between these 2 quantities? from my textbook defines resistivity as a specific property of a material and is = E/J where the resistance is the resistivity over a unit length and area. So I suppose the resistance is a measures of resistivity over a volume...

I've been googling around but i seems not able to find why CuNi have decreasing resistivity when temperature is increased at the range of 20 celcius - 80 celcius. Please enlighten me! thanks a bunch!

Homework Statement anyone can give me the methodology to do the lab test about the electrical resistivity, porosity, saturation index and salinity of soil Homework Equations The Attempt at a Solution

A carbon wire and a Nichrome wire are connected one after the other. If the combination has total resistance of 10.0 k ohm at 20°C, what is the resistance of each wire at 20°C so that the resistance of the combination does not change with temperature?(resistivity at 20°C of: nichrome= 1.5x10^-6...

Q: What is the quantum mechanical expression for resistivity of Plasma?

Homework Statement Considering silver as a plasma, I have taken the equation of motion for electrons in an electric field and found the resistivity to be \sigma_{N}=\frac{Ne^{2}}{m_{e}(i\omega + \tau^{-1})} The first part of the questions asks me to calculate the scattering time \tau at low...

Hi guys, I am trying to work out ρ in an experiment. Ive got down to ρ/AxV = 6.4 I know V = 2 and A=0.0907mm, but it should be m. If i then work it out i get a stupidly small answer. Anyone help me out. Its like 0.0016096

1. A wire of a 6.0\Omega resistance is stretched to three times its original length. Assume the diameter and resistivity have stayed the same, what is its new resistance? 2. R=\stackrel{\rho L}{A} 3. Since the only thing that's changed in the equation is L, having tripled, I was...

Homework Statement A 530 W heating coil designed to operate from 110 V is made of Nichrome wire 0.500 mm in diameter. (a) Assuming that the resistivity of the Nichrome remains constant at its 20.0°C value, find the length of wire used. (b) If the diameter of the wire were doubled...

Homework Statement A piece of Nichrome wire has a radius of 8.6 x 10^-3 m. It is used in a laboratory to make a heater that dissipates 575 W of power when connected to a voltage source of 120 V. Ignoring the effect of temperature on resistance, estimate the necessary length of wire...

Hi guys, I am currently in my AS year and a piece of coursework on resistivity of metals, how you derive the equation. But for the coursework i have to write an abstract on it, linking my experiment to a case study, does anyone have any good websites or information to help me out. This is...

HELP!A problem on resistivity Homework Statement For some application it is important that the value of a resistance not change with temperature. For example, suppose you made a 3.70 KΩ resistor from a carbon resistor and a Nichrome wire-wound resistor connected together so the total...

]1. A 1.3 cm length of tungsten filament in a small lightbulb has a resistance of 0.032 ohms. Find its diameter. Given: Length= 1.3 cm= .013m R= 0.032 ohms resistivity= 5.6e-8 ohms*meter [b]2. A= pi (r^2) R= resistivity (Length/ Area) The Attempt at a Solution R= resistivity...

[b]1. A 1.3 cm length of tungsten filament in a small lightbulb has a resistance of 0.032 ohms. Find its diameter. Given: Length= 1.3 cm= .013m R= 0.032 ohms resistivity= 5.6e-8 ohms*meter [b]2. A= pi (r^2) R= resistivity (Length/ Area) The Attempt at a Solution R=...

Hey I had a question on my quiz where it asked for the Resistance of aluminum at 600 deg C. But the formula rho-rho(i) = rho(i)a(T-T(i)) only finds the value of the resistivity at 600 deg C how do I convert it to resistance without more given info? Question: A spool of aluminum wire has a...

Homework Statement "A metal wire has a resistance of 10 ohms at a temperature of 20 degrees C. If the same wire has a resistance of 10.55 ohms at 90 degrees C, what is the resistance of this same wire when its temperature is -20 degrees C?" Homework Equations I am not exactly having...

What's the difference between resistivity and resistance?

Pls help me..thanks Homework Statement 17. How long should a copper wire 20 mills in diameter be for it to have a resistance of 5.0Ω? 20. An electric motor draw 10 A from a 240-V source 120 ft away. What is the minimum diameter of the copper wire in mills if the voltage drop is not to...

Homework Statement Two of the MHD equations can be formulated as \vec{E} + \vec{v} \times \vec{B} = \eta \vec{J} \nabla \times \vec{B} = \mu_0 \vec{J} where [itex]\eta[/tex] is the resistivity of the plasma. a.) Derive an equation for the magnetic field at very high resistivity and...

Hello guys. My name is Luqman, and I am a new member of this forum. Currently studying in Japan on Metallic Glass/Glassy Metal/Metallic Alloy, which is a branch of solid state physics. I have a million-dollar question though concerning metallic glass, which I would really appreciate if...

Homework Statement i need to find the radius of a copper wire given the following data: resistivity is 0.25 ohm meter length of wire is 200 m Homework Equations roe=RS/I roe=resistivity R= resistance of material S=cross sectional area I= length of specimen The Attempt at a...

In a problem it states that: A 10.71 V battery is connected to a resistive strip that consists of three sections with the same cross-sectional areas but different conductivities. In the solution to the problem it stipulates that the current density of the three sections are equal. Where in...