Question: What is the resistivity of a material if a wire of length 2 m and cross-sectional area 1 mm² has a resistance of 4 ohms?
Options:
Correct Answer: 4 x 10^-6 Ω·m
Solution:
Resistivity (ρ) = R * (A / L) = 4 * (1 x 10^-6 / 2) = 4 x 10^-6 Ω·m.