Does voltage drop in a series circuit?

Does voltage drop in a series circuit?

• A. Yes; the sum of voltage drops across all components equals the applied voltage
• B. No; voltage drops to zero
• C. Voltage is the same across each resistor
• D. Voltage increases along the circuit

Answer: (A)

In a series circuit, the same current flows through every component, and the voltages across those components must add up to the voltage supplied by the source. This is Kirchhoff’s Voltage Law in action: energy per unit charge delivered by the source is spent (as voltage drops) across each element along the loop, and the total drop equals the applied voltage. That’s why the correct statement is that the sum of voltage drops across all components equals the applied voltage. The voltage across individual resistors in series can be different—determined by V = I R since the current is the same through all elements, so the larger the resistance, the larger the share of the total voltage. For example, with a 9 V source and two resistors in series of 3 Ω and 6 Ω, the current is 1 A, so the voltage drops are 3 V and 6 V, totaling 9 V. The other options don’t fit a series circuit: voltage does not drop to zero along the loop, the voltage is not the same across each resistor in series, and it does not increase as you move through the circuit.

In a series circuit, the same current flows through every component, and the voltages across those components must add up to the voltage supplied by the source. This is Kirchhoff’s Voltage Law in action: energy per unit charge delivered by the source is spent (as voltage drops) across each element along the loop, and the total drop equals the applied voltage.

That’s why the correct statement is that the sum of voltage drops across all components equals the applied voltage. The voltage across individual resistors in series can be different—determined by V = I R since the current is the same through all elements, so the larger the resistance, the larger the share of the total voltage.

For example, with a 9 V source and two resistors in series of 3 Ω and 6 Ω, the current is 1 A, so the voltage drops are 3 V and 6 V, totaling 9 V.

The other options don’t fit a series circuit: voltage does not drop to zero along the loop, the voltage is not the same across each resistor in series, and it does not increase as you move through the circuit.