Question

2. Find the resistance of a wire of length 44m and diameter 0.07m
which has a resistivity of
$7 \times {10 }^{ - 8} ohm \: m$


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Answer 1

$\mathfrak{Given} \begin{cases} \sf{Length\ (l)\ =\ 44m} \\ \\ \sf{Diameter\ (d) =\ 0.07\ m} \\ \\ \sf{Resistivity\ (\rho)\ =\ 7\ \times\ 10^{-8} \Omega m} \end{cases}$

• Radius = 0.07/2 = 0.035 m

➝ R = ρL/A

➝ R = ρL/πr²

➝ R = [(7 * 10^-8) * 44]/(3.14 * 0.001225)

➝ R = (308 * 10^-8)/(0.0038465)

➝ R = 0.0008007279 Ohms