PLEASE HELP ME WITH THIS ONE QUESTION A cylindrical copper wire has a resistance of 10 Ω across a 1-meter length. The resistivity of

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PLEASE HELP ME WITH THIS ONE QUESTION
A cylindrical copper wire has a resistance of 10 Ω across a 1-meter length. The resistivity of copper is 1.7 x 10^-8 Ω-m. What is the cross-sectional area of the wire?

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Ngọc Hoa 5 years 2021-08-13T17:32:54+00:00 1 Answers 27 views 0

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  1. thanhha
    0
    2021-08-13T17:34:33+00:00
    Reply

    Resistance
    R
    of a conducting wire of length
    l
    and of area of cross section
    A
    is given by the expression
    R
    =
    ρ
    l
    A

    where
    ρ
    is resistivity or specific resistance of the material of the conductor.
    Inserting given values in the expression in SI units we get
    34
    =
    (
    1.7
    ×
    10
    −
    8
    )
    l
    π
    (
    0.1
    1000
    )
    2
    4

    ⇒
    l
    =
    34
    1.7
    ×
    10
    −
    8
    ×
    π
    4
    (
    0.1
    1000
    )
    2

    ⇒
    l
    =
    15.71

    m
    , rounded to two decimal places.

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