Question

Calculate the area of cross section of a wire if its length is 1.0 m, its resistance is 23Ω and the resistivity of the material of the wire is 1.84 x 10-6 Ωm.

Answer 1

R = p × l/A

• p = resistivity
• l = length
• A = Cross section area

Given:

• p = 1.84 × 10^(-6)
• l = 1 m
• R = 23

Solution

→ 23 Ω = 1.84 × 10^(-6) × 1/A

→ 23 = [1.84 × 10^(-6)]/A

→ A = 1.84 × 10^(-6)/23

→ A = 0.08 × 10^(-6)

→ A = 8 × 10^(-8)

Hence cross section area of wire is 8 × 10^(- 8).