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Difference between Resistance and resistivity

  1. Sep 13, 2009 #1
    What is the difference between these 2 quantities?

    from my text book 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)
     
  2. jcsd
  3. Sep 13, 2009 #2

    Doc Al

    User Avatar

    Staff: Mentor

    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"
     
    Last edited by a moderator: Apr 24, 2017
  4. Sep 13, 2009 #3

    Dale

    Staff: Mentor

    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.
     
  5. Sep 13, 2009 #4
    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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