2) Determine the resistance at 20 degrees Celsius, of 25m of solid aluminum round wire having a radius of 2mm. (Recall the relationship R=pl/A. The resistivity for Aluminum at 20 degrees Celsius = 2.8 x 10-8 Ωm).

Answer 1

2. radius = 2 mm = 0.002 meters.
A = pi*r^2 = 3.14 * (2*10^-3)^2 = 1.26*10^-5 m^2.

R = p*L/A = 2.8*10^-8 * 25/1.26*10^-5 = 0.056 Ohms.