1. The problem statement, all variables and given/known data Please help me answer thew question in the image. 2. Relevant equations Current Density J=conductivity X Electric field 3. The attempt at a solution As the current density depends on the conductivity of the material through which the electrons constitutuing it are flowing hence the current density in copper should be more than iron due to greater conductivity of copper. Hence negative charge should accumulate at the junction of copper and iron.