A wire of length 100cm and cross-sectional area 2.0 \times 10-3cm2 has a resistance of 0.10 \omega. Calculate its electrical conductivity.
A
2.0 × 10-6 ω-1cm-1
B
5.0 × 105 ω-1cm-1
C
2.0 × 106 ω-1cm-1
D
5.0 × 10-6 ω-1cm-1
E
5.0 × 107 ω-1cm-1
Verified Correct Answer: B.
Physical Principles & Numerical Solution
Electrical conductivity = the reciprocal of resistivity
but resistivity(ρ) = \(\frac{R\times A}{L}\)
resistivity(ρ) = \(\frac{ 2.0 \times 10^{-3} \times0.1}{100}\) = 0.000002
electrical conductivity(σ) = \(\frac{1}{ρ}\)
σ = \(\frac{1}{0.000002} = 500000\omega^{-1}cm^{-1}\)
Source: Myschool Past Questions Archive (Record #42914)