The resistance of a rectangular block of copp | vedclass

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(C) The resistance $R$ of a conductor is given by the formula $R = \rho \frac{l}{A}$,where $\rho$ is the resistivity,$l$ is the length,and $A$ is the

Vedclass · Accepted Answer

$1.6 	imes 10^{-8} \,\Omega \cdot m$

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(C) The resistance $R$ of a conductor is given by the formula $R = ho \frac{l}{A}$,where $ho$ is the resistivity,$l$ is the length,and $A$ is the cross-sectional area.Given dimensions are $2 \,mm 	imes 2 \,mm 	imes 5 \,m$. The current flows between the two square faces,so the length $l = 5 \,m$.The cross-sectional area $A = 2 \,mm 	imes 2 \,mm = 4 \,mm^2 = 4 	imes 10^{-6} \,m^2$.The resistance $R = 0.02 \,\Omega$.Substituting these values into the formula:$0.02 = ho \frac{5}{4 	imes 10^{-6}}$$ho = \frac{0.02 	imes 4 	imes 10^{-6}}{5}$$ho = \frac{0.08 	imes 10^{-6}}{5}$$ho = 0.016 	imes 10^{-6} \,\Omega \cdot m = 1.6 	imes 10^{-8} \,\Omega \cdot m$.

The resistance of a rectangular block of copper of dimensions $2 \,mm \times 2 \,mm \times 5 \,m$ between two square faces is $0.02 \,\Omega$. What is the resistivity of copper?

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