Question

2. The electrical resistance R of a wire varies inversely with the square of its diameter d. If a wire with a

Answer 1

Answer:

$0.225 \Omega =225 m\Omega$

Step-by-step explanation:

We know (Ohm second law) that $R= \frac{k}{d^2}$ where k inlcudes the rest of the parameters (material, lenght). In our situation we have k= $0.4\cdot9 \Omega mm^2$. The moment the diameter becomes 8mm R becomes

$R= {{0.4\cdot 9}\over{16}} \Omega = 0.225 \Omega$