Question

A copper wire has a diameter of `0.5mm` and resistivity of `1.6*10^-8Omegam`. What will be the length of this wire to make its resistance `102Omega`?

Answer 1

`"1252 m"`

Explanation:

Resistance of a wire is given by the formula

`"R" = "ρL"/"A"`

`"L" = "RA"/ρ = ("102 Ω" × π (0.5/2 × 10^-3\ "m")^2)/(1.6 × 10^-8\ "Ω m") ≈ "1252 m"`