What is the difference between a series and a parallel electrical circuit?

• A. The current is the same through every component.
• B. The voltage across each component in a series is the same.
• C. There are multiple paths for current in a series.
• D. There is one path for current and the same current flows through all components.

Answer: (D)

The idea being tested is how current behaves in series versus parallel wiring. In a series circuit there is only one path for the current, so the same current flows through every component one after another. Electrons must pass through each component in turn, so the current is identical at every point along the loop. The voltages across the components, meanwhile, add up to the total supply voltage.

In a parallel circuit there are multiple paths for the current to take. The voltage across each branch is the same because each branch is connected across the same two points, but the current can split among the branches and may be different in each path. The total current is the sum of the currents in all branches.

So the statement describing one path for current and the same current flowing through all components matches a series circuit, which is how it differs from a parallel circuit.