Understanding Kirchhoff's Voltage Law (KVL)

The question asks to identify the law that states, "The sum of voltages around a closed loop circuit is equal to zero." This fundamental principle in electrical circuit analysis is known as Kirchhoff's Voltage Law (KVL).

Kirchhoff's Voltage Law Explained

Kirchhoff's Voltage Law, often abbreviated as KVL, is based on the conservation of energy. It states that for any electrical circuit, the sum of the voltage drops across all components in a closed loop must equal the total voltage supplied by the source(s) within that loop. Mathematically, this is expressed as:

$$ \sum_{loop} V = 0 $$

This means if you traverse a closed loop in a circuit and add up all the voltage rises (like from a battery) and subtract all the voltage drops (across resistors, for example), you should end up back at zero.

Analyzing Other Options

Let's look at why the other options are not the correct answer:

• Voltage divider rule: This rule helps calculate the voltage across a specific resistor in a series circuit. It doesn't state that the total voltage in a loop is zero.
• Current division rule: This rule applies to parallel circuits and describes how current splits between different branches. It deals with current, not the sum of voltages in a loop.
• Kirchhoff's Current Law (KCL): This law deals with current at a node (junction). It states that the algebraic sum of currents entering a node is equal to the algebraic sum of currents leaving the node ($\sum I_{in} = \sum I_{out}$ or $\sum_{node} I = 0$). This is different from KVL's focus on voltages in a loop.

Conclusion on KVL

Therefore, the law that specifically addresses the sum of voltages around a closed loop equaling zero is Kirchhoff's Voltage Law.