Question

Consider a copper wire with a diameter of 0.450 mm. If you want to cut a piece of the wire so it has a resistance of 3.25 Ω, how long should your piece of wire be? (Resistivity of copper: 1.68x 108 Ω m) A. 0.343 m B. 9.79 m 13. C. 2.91 m D. 123 m E. 30.1 m

Answer 1

Answer:

30.7m

Explanation:

You can use the following equation:

ρ = R * $\frac{S}{l}$

Where ρ is the resistivity, R is the resistance, S is the Cross-sectional Area and l is the length of the wire.

We issolate l in the equation and solve with the data we have:

l = R * $\frac{S}{p}$ = 3.25 Ω * $\frac{0.25 *\pi * ((0.45/1000)^2}{1.68*10^-8}$

l =  30.7m