Answer :
Answer:
The ratio of diameter of copper wire to the iron wire is 0.42.
Explanation:
length of both the wires is same as L and resistance is R.
resistivity of copper = 1.7 x 10^-8 ohm m
resistivity of iron = 9.7 x 10^-8 ohm m
Let the diameter of copper is d and for iron is d'.
The formula of the resistance is
[tex]R = \rho\times\frac{L}{A}\\\\R = \rho\times\frac{4L}{\pi d^2}.... (1)\\And\\ R = \rho'\times\frac{4L}{\pi d'^2}.... (2)\\\\comparing (1) by (2)\\\\1.7\times10^{-8}\times\frac{4L}{\pi d^2}=9.7\times10^{-8}\times\frac{4L}{\pi d'^2}\\\\d : d' = 0.42[/tex]