Difference between Resistance and resistivity

AI Thread Summary
Resistivity is defined as a specific property of a material, represented by the equation E/J, while resistance is calculated using the formula Resistance = ρL/A, where ρ is resistivity, L is length, and A is cross-sectional area. Resistance depends on the dimensions of the material, making it a property of a specific device, whereas resistivity is intrinsic to the material itself. The relationship indicates that resistance increases with length and decreases with area, highlighting the importance of geometry in electrical applications. Understanding resistivity allows for easier calculations of resistance when dimensions are known. Overall, resistivity is a more fundamental concept in material science compared to resistance.
SpartanG345
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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

Resistance = pL/A

thats what i think but i am not sure if i am right

PS i am sorry if this is a noob question, but my answer differed by one provided on yahoo answers, but then again yahoo answers is only yahoo answers( i got worried)
 
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SpartanG345 said:
Resistance = pL/A
This is what you need. Resistance of a piece of material is proportional to its length and inversely proportional to its area. The proportionality constant p is called the resistivity, which is a property of the kind of material.

Read this: http://hyperphysics.phy-astr.gsu.edu/HBASE/electric/resis.html#c2"
 
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Resistance is a property of a device and resistivity is a property of a material. For a mechanical analogue you might think of the difference in strength between a piece of aluminum foil and an aluminum baseball bat. They are both made out of aluminum, so they both have the same Young's modulus, but they are shaped differently so they have different stiffness.
 
SpartanG345 said:
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

Resistance = pL/A

thats what i think but i am not sure if i am right

PS i am sorry if this is a noob question, but my answer differed by one provided on yahoo answers, but then again yahoo answers is only yahoo answers( i got worried)

Suppose you set me this question:What is the resistance of aluminium?I would answer that It's a silly question because it depends on the cross sectional area and the length of the aluminium.If you now asked me what is the resistivity of aluminium I would refer to a data book and come back with an answer.Knowing the resistivity and the dimensions of the aluminium it is easy to work out the resistance.Resistivity,therefore, is a much more useful concept because it is a property of the material and independant of its dimensions.
 
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