Which type of current is capable of exerting a chemical action when flowing through a conductor?

• A. Alternating current
• B. Joule's law
• C. Direct current
• D. None of these

Answer: (C)

Direct current is capable of exerting chemical action because it provides a constant, one-way flow of charge. With unidirectional current, ions are continuously driven toward the opposite electrode, enabling sustained electrochemical reactions at the electrode surfaces (oxidation at one electrode and reduction at the other). This is what drives processes like electrolysis and electroplating. In contrast, alternating current keeps reversing direction, so any chemical changes at the electrodes tend to cancel out over time, and the main observable effect is heating rather than a net chemical action. Joule's law, meanwhile, isn’t a type of current at all—it describes how much heat a current causes in a conductor. So the option describing direct current best explains the ability to produce chemical changes.