ASVAB (Armed Services Vocational Aptitude Battery)Electronics Information (EI)Medium
In a parallel circuit, if one of the branches containing a light bulb burns out (becomes an open circuit), what happens to the current in the other branches?
- AIt stops flowing entirely.
- BIt decreases.
- CIt remains the same.
- DIt increases.
Show answer & explanationAnswer & explanation
Correct answer: C. It remains the same.
In a parallel circuit, each branch operates independently, receiving the full source voltage. If one branch opens, the total resistance of the circuit increases, but the voltage across the remaining parallel branches remains unchanged, so the current through them also remains the same (assuming a constant voltage source).
Why the other options are wrong
- A. This would only happen if the main power source failed or the entire circuit became open, not just one branch.
- B. This would happen if the source voltage dropped or the resistance of the other branches increased, which is not stated.
- D. This would happen if the total resistance decreased, which is not the case for an open branch.
Parallel Circuit
A circuit in which components are connected across the same two points, providing multiple paths for current flow.
- Voltage is the same across all parallel components.
- Total current is the sum of currents in individual branches (I_total = I1 + I2 + ...).
- Total resistance is less than the smallest individual resistance (1/R_total = 1/R1 + 1/R2 + ...).
Memory trick: Parallel: Paths for Current, Same Voltage, Shared Load.