Define Ohm's Law.

Ohm's Law is foundational in electrical theory and defines the relationship between voltage, current, and resistance in an electrical circuit. It states that the current (I) flowing through a conductor between two points is directly proportional to the voltage (V) across the two points and inversely proportional to the resistance (R) of the conductor. This relationship is typically expressed using the formula V = I × R, which succinctly captures how these three crucial electrical parameters are interconnected.

Understanding this relationship is key for analyzing and designing electrical circuits, as it allows one to calculate how changes in one parameter affect others. For example, increasing the voltage applied to a circuit will increase the current if the resistance remains constant. Conversely, increasing the resistance while keeping the voltage constant will reduce the current. This essential principle helps technicians and engineers troubleshoot and optimize circuits effectively.

The other options, while related to electrical concepts, do not encapsulate the essence of Ohm's Law. The ratio of voltage to current pertains to the concept of resistance but does not fully articulate the law’s broader implications. The principle governing magnetic fields and the formula for power calculations relate to different aspects of electricity, focusing either on magnetism or energy use rather than the direct relationship that Ohm's Law