In a series circuit with one lamp open, what happens to the current through the remaining lamps?

• A. The current through all lamps remains the same.
• B. The other lamps increase current.
• C. The circuit opens so all lamps go off.
• D. The current flows through the open lamp via alternate path.

Answer: (C)

In a series circuit, the current must have one complete path to flow through all components. If one lamp opens, the circuit is broken and no closed loop remains. Without a complete path, current cannot flow, so all lamps go dark. There’s no alternate route for the current to take in a simple series setup, so the break stops the entire circuit rather than increasing current through the other lamps. Reconnecting or replacing the open lamp restores the loop and lets current flow again.