Answer
$σ= 12.18 (Ω-m)^{-1}$
Work Step by Step
Given:
A cylindrical silicon specimen 7.0 mm (0.28 in.) diameter and 57 mm (2.25 in.) in length in which a current of 0.25 A passes in an axial direction. A voltage of 24 V is measured across two probes that are separated by 45 mm (1.75 in.)
Required:
electrical conductivity
Solution:
Using Equations 18.3 and 18.4:
$σ = \frac{1}{ρ} = \frac{Il}{VA} = \frac{Il}{Vπ(\frac{d}{2})^{2}}$
$σ= \frac{(0.25 A)(45 \times 10^{-3} m)}{(24 V)π(\frac{7 \times 10^{-3} m}{2})^{2}} = 12.18 (Ω-m)^{-1}$
