What does the direction of current flow depend on?

• A. Which metal is more active
• B. Distance between metals
• C. Electrolyte temperature
• D. Area ratio

Answer: (A)

The main idea is that current direction in a galvanic couple is set by which metal is more electrochemically active. The more active metal has a greater tendency to oxidize, so it becomes the anode and supplies electrons. Those electrons flow through the external circuit to the less active metal, which acts as the cathode, making conventional current move from the more active metal toward the less active one. The other factors—distance between metals, electrolyte temperature, and area ratio—affect how much current can flow (rate or magnitude) but not the direction, which is determined by which metal is more active.