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How does the resistance of a copper wire change when both the length and diameter of the wire are double?

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How does the resistance of a copper wire change when both the length and diameter of the wire are doubled? (a) It decreases by a factor of two. (b) It increases by a ...show more
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the resistance of a wire is given by

R=rho L/A where rho is a characteristic of the material, L is the length and A is the cross sectional area

if the diameter is doubled then the cross sectional area is quadrupled; the resistance varies as 2L/4A or 1/2 the original resistance; in this case, the resistance decreases by a factor of 2, or Ans A is correct
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Other Answers (1)

  • Waheed answered 5 years ago
    Resistance = k x length / ( pi/4 ) d^2
    Let Resistance is R ohms
    (a)
    It decreases by a factor of two. new Resistance 4/2 = 2 R

    (b)
    It increases by a factor of two. new resistance = 2/4 = 0.5 R

    (c)
    It increases by a factor of four.new resistance = 4/16 = 0.25 R

    (d)
    It decreases by a factor of four. new resistance = 16 /4 = 4 R

    (e)
    It does not change.new resistance = R
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  • How does the resistance of a copper wire change when both the length and diameter of the wire are double?
    How does the resistance of a copper wire change when both the length and diameter of the wire are doubled?

    (a)
    It decreases by a factor of two.
    (b)
    It increases by a factor of two.
    (c)
    It increases by a factor of four.
    (d)
    It decreases by a factor of four.
    (e)
    It does not change.
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