Explain Kirchhoff's Voltage Law (KVL) and provide an example application.

Kirchhoff's Voltage Law states that the algebraic sum of all voltages around any closed loop in a circuit equals zero, based on conservation of energy. For example, in a series circuit with a 12V source and two resistors with 7V and 5V drops respectively, KVL confirms: 12V - 7V - 5V = 0. KVL is fundamental for mesh analysis and solving circuit equations.