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    Current Electricity: Resistance and Resistivity

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    Stretch That Wire

    A wire of initial length L0 and radius r0 has a measured resistance of 1.56 ohm. The wire is drawn under tensile stress to a new uniform radius of r = 0.420r0. What is the new resistance of the wire?

    © BrainMass Inc. brainmass.com December 24, 2021, 8:37 pm ad1c9bdddf
    https://brainmass.com/physics/resistance/current-electricity-resistance-resistivity-294562

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    A wire of initial length L0 and radius r0 has a measured resistance of 1.56 ohm. The wire is drawn under tensile stress to a new uniform radius of r = 0.420r0. What is the new resistance of the wire?

    The resistance of a conductor is given by

    Here  is the resistivity, L is the length (thickness) and A is the area of the conductor.
    As initially the length is L0 and the radius is r0 the resistance is given by
    ------------------------------ (1)
    When the wire is stretched, its volume remains the same and thus

    Substituting value of new radius r the new length L is given by

    Gives
    Hence the new resistance of the wire is given by

    Or
    Substituting the value of LHS from equation (1) in above equation we get

    Thus the new resistance of the wire will be 50.1 .

    This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here!

    © BrainMass Inc. brainmass.com December 24, 2021, 8:37 pm ad1c9bdddf>
    https://brainmass.com/physics/resistance/current-electricity-resistance-resistivity-294562

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