Ohm’s Law, while fundamental in understanding electrical circuits, has several drawbacks and limitations. One drawback is that it assumes the resistance (R) of a circuit remains constant regardless of changes in voltage (V) or current (I). In reality, resistance can vary due to factors such as temperature changes, aging of components, or nonlinear behavior in some materials. This can lead to inaccuracies in predictions based solely on Ohm’s Law.

The failure of Ohm’s Law occurs when the relationship between voltage, current, and resistance deviates from linearity. Non-ohmic materials, such as diodes and transistors, do not obey Ohm’s Law because their resistance changes with voltage or current. For example, in semiconductors, the current may increase exponentially with voltage, violating the linear relationship predicted by Ohm’s Law.

In the context of Class 12 current electricity studies, Ohm’s Law has limitations primarily in its applicability to linear circuits with constant resistances. Students learn that Ohm’s Law is valid for conductors whose resistance remains steady under varying voltage and current conditions. However, in real-world scenarios involving components like diodes or complex networks, Ohm’s Law may not accurately describe circuit behavior, requiring additional theories like Kirchhoff’s laws or circuit analysis methods.

Beyond ideal resistive circuits, factors such as varying temperatures affecting resistance, transient effects in capacitors and inductors, and nonlinear behaviors in semiconductor devices can challenge the straightforward application of Ohm’s Law. Engineers and physicists often emphasize the need for broader circuit analysis techniques to account for these complexities.

Ohm’s Law is not always valid because it assumes a linear relationship between voltage, current, and resistance. In cases where resistance varies with voltage (as in semiconductors) or current (as in thermistors), Ohm’s Law fails to accurately predict circuit behavior. Additionally, at very high frequencies or in non-steady-state conditions, where reactance in capacitors and inductors becomes significant, Ohm’s Law becomes insufficient for describing the complex interactions of voltage and current.

Ohm’s Law is advantageous because it provides a simple and intuitive relationship between voltage, current, and resistance in linear electrical circuits. This relationship allows engineers and technicians to predict and calculate the behavior of circuits accurately under normal operating conditions. It forms the foundation for understanding basic circuit analysis and serves as a starting point for more advanced topics in electronics and electrical engineering. Additionally, Ohm’s Law is widely applicable in practical scenarios involving resistive components, making it a fundamental tool in the field of electrical sciences.