If a metal wire 4m long and cross-sectional area 0.8 mm² has a resistance of 60; find the resistivity of the wire?

A. 5.3×10^-7
B. 3.0×10^-5
C. 1.2×10^-6
D. 3.2×10^-6

Correct Answer:

Option C – 1.2×10^-6

Explanation

P=RA/l (Ωm)

P=6×0.8/4 (Ωm)

P=1.2×10^−6Ωm