Question

The resistance of a wire 2.5 m long and 0.9 mm in diameter is 0.07 ohm. What is the resistivity of the material of the wire?

Answer 1

l=2.5m

d=0.9mm=> r=d/2=0.9/2=0.45mm=0.45x10⁻³m

R=0.07Ω

R=ρl/a

ρ=Ra/l

 =(0.07 XπX0.45²X10⁻⁶)/2.5

 = 1.78x10⁻⁸Ωm