What principle states that the induced electromotive force is directed to oppose the change in magnetic flux?

Lenz's law is a fundamental principle in electromagnetism that specifically addresses the behavior of induced electromotive force (EMF) in response to changing magnetic fields. According to Lenz's law, the direction of the induced EMF is such that it creates a current whose magnetic field opposes the initial change in magnetic flux that produced it.

This principle is a direct consequence of the conservation of energy. If the induced current were to flow in a direction that reinforced the change in magnetic flux, it would lead to a situation where energy could be created from nothing, violating the conservation law. Instead, Lenz's law ensures that the induced current acts to counteract the change, effectively maintaining energy balance in the system.

Understanding Lenz's law is critical for analyzing electrical systems, particularly in applications like induction motors and transformers, where changing magnetic fields play a key role. The opposing nature of induced EMF exemplifies how systems strive to maintain equilibrium, leading to a more comprehensive understanding of electromagnetic phenomena.