The resistance of a 100-cm wire of cross sectional area 2 × $10^{- 6}$ $m ^ { 2 }$ is 400 Ω. What is the resistivity of the material from which this wire is made?
A) 0.80 × $10^{ - 4}$ Ω ∙ m
B) 8.0 × $10 ^{- 4}$ Ω ∙ m
C) 0.80 × $10 ^ { - 5 }$ Ω ∙ m
D) 0.80 × $10^{ - 6}$ Ω ∙ m
E) 8.0 × $10 ^{- 6}$ Ωv

Question

Quizplus · Accepted Answer

The resistivity $\rho$ is calculated using the formula $\rho = R \cdot \frac{A}{L}$, where $R$ is resistance, $A$ is cross-sectional area, and $L$ is length. Substituting the given values: $\rho = 400 \cdot \frac{2 \times 10^{-6}}{1} = 8.0 \times 10^{-4}$ Ω ∙ m.

The Resistance of a 100-Cm Wire of Cross Sectional Area 10−610^{- 6}10−6

The Resistance of a 100-Cm Wire of Cross Sectional Area $10^{- 6}$