A Copper ( Cu ) rod of length 25   cm and cross-sectional area 3   mm 2 is joined with a similar…

A Copper $\left(\mathrm{Cu}\right)$ rod of length $25 \mathrm{cm}$ and cross-sectional area $3{ \mathrm{mm}}^2$ is joined with a similar Aluminium $\left(\mathrm{Al}\right)$ rod as shown in figure. Find the resistance of the combination between the ends $A$ and $B.$

(Take resistivity of Copper $=1.7\times {10}^{-8} \mathrm{\Omega m}$, Resistivity of aluminium $=2.6\times {10}^{-8} \mathrm{\Omega m}$)