If one path in a parallel circuit fails, what usually happens to the other paths?

• A. The current will stop entirely
• B. Other paths may continue to function
• C. The voltage across all branches increases
• D. The circuit becomes a series circuit

Answer: (B)

In a parallel circuit, each branch is connected directly to the same voltage source, so each device on its own path can operate independently of the others. If one path fails in an open way, that branch simply disappears from the circuit, and the remaining branches still have the full source voltage across them. The current in the failed path drops to zero, while the currents in the other paths continue to flow according to their own resistances and the same supply. The total current drawn from the source may decrease, but the voltage across the remaining branches stays essentially the same. So other paths may continue to function.