In a series circuit, which statement is true?

• A. The current is the same through all components
• B. The voltage across each component is equal
• C. The total current is the sum of branch currents from each component
• D. The resistance is independent of each component's value

Answer: (A)

Current is the same through every component in a series circuit. Since there’s only one path for the current, the same amount of charge that flows into the first component must flow through and out of the last, so the current you measure is the same everywhere along the loop. The voltage, however, can differ from one component to the next because V = I·R, and the current I is the same while each component may have a different resistance. The sum of all these voltages equals the total supply voltage.

Remember, in a series circuit there isn’t a split of current, so you don’t add branch currents to get the total current. And the total resistance isn’t independent of component values; it’s the sum of the individual resistances, so changing any component changes the overall resistance.