Question

Resistence of a wire of length 1m is 26at 20C. If the diameter of the wire is 0.3mm, what will be the resistivity of the metal at the temperature? Using table 12.2, predict the material of the wire.

Answer 1

Answers

We are given the resistance R of the wire = 26 Ω, the diameter

d = 0.3 mm = 3 × 10-4 m, and the length l of the wire = 1 m.

Therefore, from Eq. (12.10), the resistivity of the given metallic wire is

ρ = (RA/l) = (Rπd2/4l)

Substitution of values in this gives

ρ = 1.84 × 10–8 Ω m

The resistivity of the metal at 20°C is 1.84 × 10–8 Ω m.