What does Kirchhoff's Voltage Law (KVL) state?

• A. The sum of voltages around a closed loop equals zero
• B. The sum of currents entering a node equals the sum leaving
• C. The product of voltages around a loop equals zero
• D. The impedance around the loop equals zero

Answer: (A)

Kirchhoff's Voltage Law states that the algebraic sum of all voltages around any closed loop is zero. As you move around a loop, you assign a positive sign to voltage rises (like going from low to high potential) and a negative sign to drops (like across a resistor or source when you move with the drop). The total must cancel out because energy is conserved: you can’t gain or lose net energy by just looping through elements. A simple view is a loop with a battery and a resistor: the battery provides a rise, the resistor creates a drop, and when you add all the changes around the loop, they sum to zero.

Why the other ideas don’t fit: summing currents at a node is Kirchhoff’s Current Law, not about voltages around a loop. Taking the product of voltages around a loop isn’t a general circuit principle. And treating impedance around the loop as zero isn’t how KVL describes circuit behavior.