Question

The rod in the figure shown is made of two materials. Each conductor has a square crosssection 5mm on a side. The first material has a resistivity of 8x10-3Ω-m and is 35cm long, while the second material has a resistivity of 10x10-3Ω-m and is 50cm long. What is the resistance of the rod?

Answer 1

$$R=\rho_1\frac{l_1}{A_1}+\rho_2\frac{l_2}{A_2}\\ R=0.008\frac{0.35}{0.005^2}+0.01\frac{0.5}{0.005^2}=312\Omega$$