Equal potentials are applied on an iron and c | vedclass

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(B) Given that the potential difference $V$ and length $L$ are the same for both wires, and the current $I$ is also the same.From Ohm's law, $V = IR$,

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About $2.4$

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(B) Given that the potential difference $V$ and length $L$ are the same for both wires, and the current $I$ is also the same.From Ohm's law, $V = IR$, so the resistance $R$ must be the same for both wires.The resistance is given by $R = ho \frac{L}{A} = ho \frac{L}{\pi r^2}$.Since $R$, $L$, and $\pi$ are constant, we have $\frac{ho_{	ext{iron}}}{r_{	ext{iron}}^2} = \frac{ho_{	ext{copper}}}{r_{	ext{copper}}^2}$.Therefore, $\frac{r_{	ext{iron}}^2}{r_{	ext{copper}}^2} = \frac{ho_{	ext{iron}}}{ho_{	ext{copper}}}$.Taking the square root, $\frac{r_{	ext{iron}}}{r_{	ext{copper}}} = \sqrt{\frac{ho_{	ext{iron}}}{ho_{	ext{copper}}}} = \sqrt{\frac{1.0 	imes 10^{-7}}{1.7 	imes 10^{-8}}} = \sqrt{\frac{10}{1.7}} \approx \sqrt{5.88} \approx 2.42$.Thus, the ratio is about $2.4$.

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