Answer:
The answer is below
Step-by-step explanation:
The electrical resistance R of a wire varies inversely with the square of its diameter d:
R ∝ 1 / d
Let k represent the constant of proportionality, hence we can represent the statement as an equation:
[tex]R=\frac{k}{d^2}\\ \\when\ R=0.5 \Omega,d=2\ mm\\\\0.5=\frac{k}{2^2} \\\\k=2\\\\The\ equation\ becomes :\\\\R=\frac{2}{d^2}\\ \\When\ d=3, we\ find\ R\\\\R=\frac{2}{3^2} \\\\R=0.22\ \Omega[/tex]
