In a parallel circuit, the voltage across each branch equals the source voltage.

• A. Voltage across each branch equals the source voltage.
• B. Voltage across each branch is zero.
• C. Voltage across each branch equals branch resistance times current.
• D. Voltage across each branch equals the sum of currents times resistance.

Answer: (A)

In a parallel circuit, all branches are connected across the same two points, so they share the same potential difference as the source. If the source provides V volts, each branch has V volts across it. The current through a branch then follows Ohm’s law: I_branch = V / R_branch, and the total current is the sum of all branch currents. This shared voltage is the defining feature of parallel connections, which is why the statement about the voltage across each branch matching the source is the best description.

The notion that the branch voltage would be zero is only true if there were no source or an open circuit. Saying the branch voltage equals the branch resistance times the branch current is always true by Ohm’s law, but it doesn’t emphasize that the same voltage applies to every branch in a parallel layout. The idea involving the sum of currents times a resistance doesn’t reliably describe the voltage across a branch in a parallel network.