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A metal rod of length $10 \mathrm{~cm}$ and a rectangular cross-section of $1 \mathrm{~cm} \times \frac{1}{2} \mathrm{~cm}$ is connected to a battery across opposite faces. The resistance will be
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maximum when the battery is connected across $1 \mathrm{~cm} \times$ $\frac{1}{2} \mathrm{~cm}$ faces
maximum when the battery is connected across $1 \mathrm{~cm} \times$ $\frac{1}{2} \mathrm{~cm}$ faces
As we known that the resistance of wire is $R=\rho \frac{l}{A}$ For maximum value of $\mathrm{R}, l$ must be higher and A should be lower and it is possible only when the battery is connected across area of cross section $=1 \mathrm{~cm} \times\left(\frac{1}{2}\right) \mathrm{cm}$.
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