A wire of length L and cross-sectional area A has resistance R. What will be the resistance Rstretched of the wire if it is stretched

Question

A wire of length L and cross-sectional area A has resistance R.
What will be the resistance Rstretched of the wire if it is stretched to twice its original length? Assume that the density and resistivity of the material do not change when the wire is stretched.

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Thiên Ân 5 years 2021-08-12T03:31:10+00:00 2 Answers 15 views 0

Answers ( )

  1. diemkieu
    0
    2021-08-12T03:32:43+00:00
    Reply

    Answer:

    Explanation:

    Given:

    L2 = 2 × L1

    Using the formula,

    Resistivity, d = (R × A)/L

    Where,

    R = resistance

    A = area

    L = length

    1. d1 = (R1 × A1)/L1

    2. d2 = (R2 × A2)/L2

    Equating both 1 and 2 together,

    (R2 × A2)/L2 = (R1 × A1)/L1

    (R2 × A2)/(2 × L1) = (R1 × A1)/L1

    Assume A1 = A2,

    R2 = [(R1 × A1) × 2 × L1]/(A1 × L1)

    R2 = 2 × R1

  2. Nick
    0
    2021-08-12T03:32:51+00:00
    Reply

    Answer:

    The resistance will be twice the original resistance

    Explanation:

    This is a fairly simple question, the formular for the resistance of a wire is given as

    R = rho *length / area

    Where R = resistance

    Rho = resistivity

    L = length

    A = area

    Since the density and area are constant I.e they do not change

    R/ length = rho/ area

    The initial length is given as L, when this length is stretched to twice its original length ,it becomes 2×L = 2L

    Let x represent the resistance when the length is doubled

    R/ L = x / 2L

    x = 2LR / L ; dividing by L

    We have that x = 2R ; twice the resistance

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