In a series circuit, what happens if one component opens?

• A. The current increases in the other components.
• B. The voltage across the other components remains constant.
• C. The same current flows through all components; if one opens, current stops in all.
• D. The circuit automatically reroutes current through an alternate path.

Answer: (C)

In a series circuit, current has only one path and must be the same through every component. If one element opens, that break stops the path for current entirely, so no current can flow anywhere in the loop. With the circuit open, the current through all components drops to zero, and the voltage behavior shifts: there’s no drop across the others (in an ideal case), while the supply voltage appears across the open gap. There’s no alternate route for current in a single series path, so nothing can reroute.

So the statement that the same current would flow through all components only holds when the loop is closed; once it opens, current stops in all parts of the circuit.