If the supply voltage in that parallel circuit is doubled from 120 V to 240 V, what happens to the total current?

• A. Remains the same
• B. Increases by 50%
• C. Doubles
• D. Decreases by half

Answer: (C)

In a parallel circuit, each branch experiences the full supply voltage, and the current in a branch follows I = V/R. With the same resistances, doubling the voltage from 120 V to 240 V doubles the current through every branch. Since the total current is the sum of all branch currents, doubling each branch current doubles the total current as well. So the total current doubles. If a branch didn’t follow Ohm’s law or its resistance changed with voltage, the result could differ, but for typical parallel resistive branches, the total current doubles.