The resistivity of a 1.0 m long copper wire is 1.72 × 10^-8 Ω ∙ m and its cross sectional area is 2.0 × 10^-6 m².If the wire carries a current of 0.20 A,what is the voltage across the wire?

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Quizplus · Accepted Answer

The voltage across the wire can be calculated using Ohm's Law, $V = IR$, where $I$ is the current and $R$ is the resistance. The resistance $R$ can be found using the formula $R = \rho \frac{L}{A}$, where $\rho$ is the resistivity, $L$ is the length, and $A$ is the cross-sectional area. Substituting the given values, $R = 1.72 \times 10^{-8} \Omega \cdot m \times \frac{1.0 m}{2.0 \times 10^{-6} m^2} = 8.6 \times 10^{-3} \Omega$. Then, $V = 0.20 A \times 8.6 \times 10^{-3} \Omega = 1.72 \times 10^{-3} V = 1.7 mV$.

The Resistivity of a 1