Which law states that the total current entering a junction equals the total current leaving?

The principle that states the total current entering a junction equals the total current leaving is known as Kirchhoff's Current Law (KCL). This law is fundamental in electrical engineering and circuit analysis, as it ensures that charge is conserved within electrical circuits. KCL is based on the understanding that at any node (junction) in an electrical circuit, the sum of currents flowing into the node must equal the sum of currents flowing out. This concept aligns with the principle of conservation of electric charge, which is a foundational concept in electrical theory.

In practical applications, KCL allows engineers to analyze complex circuits by setting up equations that describe how current flows through various components in a system. Understanding KCL is crucial for tasks such as designing circuits and troubleshooting electrical systems, making it an essential aspect of electrical and instrumentation studies.