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The rate at which the energy in the wire is transformed into kinetic

  1. Apr 13, 2013 #1
    1. The problem statement, all variables and given/known data

    A potential difference of 50 mV is maintained between the ends of a 9.70 m length of wire whose cross section area is 25.0mm^2. The conductivity of the wire is 6.80 x 10^6 (ohm.m)^-1. Determine the rate at which the energy in the wire is transformed into kinetic to thermal energy.

    2. Relevant equations
    P = v^2/R

    ρ = 1/c

    R = ρ (L/A)

    Where ρ = resistivity
    c = conductivity
    A = area
    L = length
    R = Resistance
    V = Voltage
    P = power


    3. The attempt at a solution

    ρ = 1/6.80 x 10^6 = 1.471 x 10^(-7)

    R = 1.471 x 10^(-7) * ( 9.70/0.000025 )
    = 0.0570748
    P = (50 x 10^-3)/0.0570748
    = 0.0438021
    = 4.38 x 10^(-2) W

    This is my complete work. I think my workings are correct but I am not to sure of the answer. I will be glad if anyone can help.
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
    1. The problem statement, all variables and given/known data



    2. Relevant equations



    3. The attempt at a solution
     
  2. jcsd
  3. Apr 13, 2013 #2
    You have an amazing calculator

    P = (50 x 10^-3)/0.0570748
    = 0.0438021

    I think you got the correct answer
     
  4. Apr 13, 2013 #3
    Thank you.
     
  5. Apr 14, 2013 #4
    My professor says my answer is wrong.
     
  6. Apr 14, 2013 #5

    haruspex

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    I also confirm your answer.
     
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