What will be the resistance of an aluminium wire of length 1.2 m and cross sectional area \( 2.6\,\mathrm{mm^{2}} \). The resistivity of aluminium is \( 2.6\times10^{-8}\,\Omega\,\mathrm{m} \)
Answer & explanation
Correct answer: option 3
The correct answer is Option (3) → \( 1.2\times10^{-2}\,\Omega \)
The resistance of a uniform wire is \( R = \rho\,\frac{l}{A} \). First convert the area to SI units: \( 1\,\mathrm{mm^{2}} = 10^{-6}\,\mathrm{m^{2}} \), so \( A = 2.6\times10^{-6}\,\mathrm{m^{2}} \).
\( \displaystyle R = \frac{2.6\times10^{-8}\times1.2}{2.6\times10^{-6}} \)
\( R = 1.2\times10^{-2}\,\Omega \)