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Homework Help: Resistance and temp co-efficient?

  1. Feb 25, 2010 #1
    1. The problem statement, all variables and given/known data

    A conductor has cross-section of 10 cm2 and specific resistance of 7.5 ohm cm at 0 degree C
    what will be its resistance in ohm per/kilometer when the temperature is 40 degree C ?
    take temperature co-efficient of the material is 0.005 / degree C

    i cant find the solution of it. please give me solution if you can
    please help me

    2. Relevant equations
    Resistance of a wire in Ω
    R = ρL/A
    ρ is resistivity of the material in Ω-cm
    L is length in cm
    A is cross-sectional area in cm²

    3. The attempt at a solution

    R = (7.5 Ω-cm)(L) / 10 cm²
    R/L = 0.75 Ω/cm

    R/L = 0.75 Ω/cm x 100000 cm/km = 75000 Ω/km

    R/L = 75000 Ω/km x [1+ (0.005/C)*40C]
    R/L = 90000 Ω/km
  2. jcsd
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