Physics - Error Question with Solution | TestHub

$\mathrm{R}\propto {\ell }^2$ (for a given volume) $$\Rightarrow \frac{\Delta \mathrm{R}}{\mathrm{R}}\%=\frac{2\Delta \ell }{\ell }\%$$ Thus when wire is stretched by $0.1\%$ resistance increases by $0.2\%$