In a series circuit, the source voltage equals the sum of the voltage drops; if the individual drops are 2 V, 3 V, and 5 V, what is the source voltage?

• A. 2 V
• B. 10 V
• C. 3 V
• D. 5 V

Answer: (B)

In a series circuit, the source voltage equals the sum of the voltage drops across each component because the same current passes through every element and the voltages add up to the total. Add the given drops: 2 V + 3 V + 5 V = 10 V. Therefore, the source voltage is 10 volts. The single-number options correspond to individual drops, not the total supply, so they don’t represent the overall voltage.