# Connecting wires end-to-end

Two cylindrical conductors with equal cross sections but different resistivities are put end-to-end. Find the magnitude of the charge that accumulates at the boundary between the conductors if a current $$I=100\textrm{A}$$ flows in the wires. The wires are made of aluminum and copper with resistivities $$\rho_{Cu}=1.7 \times 10^{-8} \Omega\cdot m$$ and $$\rho_{Al}=2.8\times 10^{-8} \Omega \cdot m$$, respectively. This charge should be very small even for this large current $$I=100A$$.

×