Question

Calculate the cross-sectional area, in mm^2, of a piece of copper wire, 40 m length and having a resistance of 0.25 Ω. Take the resistivity of copper as 0.02x10−6 Ωm

Answer 1

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Answer:

  3.2 mm²

Step-by-step explanation:

The relevant relation is ...

  R = ρ·l/A

  0.25 Ω = (0.02×10^-6 Ωm)·(40 m)/A

  A = (0.02×10^-6)(40)/0.25 m² = 3.2 mm²