What happens when an additional branch is added to a parallel circuit?

• A. Decreases total resistance.
• B. Increases total resistance.
• C. Voltage across each branch changes.
• D. Total current from the source decreases.

Answer: (A)

In parallel circuits, adding another branch provides an extra path for current to flow, which lowers the overall resistance seen by the source. This happens because the total resistance in parallel is less than any individual branch, described by 1/R_total = sum of 1/R_i; adding a branch increases that sum, so R_total decreases. With the same supply voltage, a smaller total resistance means more current drawn from the source, since I_total = V / R_total. The voltage across each branch remains the same as the source voltage in an ideal parallel circuit, so it doesn’t change when a new branch is added. Therefore, the correct outcome is that total resistance decreases.