In a series circuit, the sum of the voltages across all components equals the source voltage.

• A. Product
• B. Sum
• C. Difference
• D. Quotient

Answer: (B)

In a series circuit, voltages add up because the same current flows through every component and the voltage drops across each element must add to the total potential difference provided by the source. This is Kirchhoff’s voltage principle: around any closed loop, the algebraic sum of voltage rises and drops is zero, so the source voltage equals the sum of the individual drops across the components. In other words, the energy per charge delivered by the source is shared across the components, and their voltage drops add together to equal the source voltage. The other operations (multiplying, taking differences, or dividing) don’t describe how voltages combine in a single loop.