Sol. $$ \begin{aligned} & I=2 \mathrm{~A} \\ & \Delta \mathrm{~V}=3.4 \mathrm{~V} \\ & \text { Using Ohm's Law } \end{aligned} $$ $$ \begin{aligned} & R=\frac{3.4}{2}=1.7 \Omega \\ & 1.7=\frac{\rho L}{A} \\ & L=\frac{1.7(A)}{\rho} \end{aligned} $$ $\mathrm{M}=$ (density volume) $$ \begin{aligned} \text { Volume } & =\frac{8.92 \times 10^{-3}}{8.92 \times 10^3}=10^{-6} \\ & L^2=\frac{1.7}{\rho}\left(10^{-6}\right)=\frac{1.7}{1.7} \times 10^2 \\ L & =10 \mathrm{~m} \end{aligned} $$