Question

Is Ohm's Law a universal law?

Answer 1

Ohm's Law is widely applicable, but it’s not considered a "universal law" in the strictest sense.

In basic terms, Ohm's Law states that the current (\(I\)) through a conductor is directly proportional to the voltage (\(V\)) applied across it and inversely proportional to the resistance (\(R\)) of the conductor. The formula is:

\[
V = I \times R
\]

However, Ohm's Law doesn’t apply to all materials or situations. Here’s why:

1. Linear materials: Ohm’s Law applies well to materials that exhibit linear relationships between voltage and current (like metals under normal conditions). In these materials, the resistance remains constant regardless of the voltage or current.
   

1. Non-linear materials: For some materials (like semiconductors, diodes, and superconductors), the relationship between voltage and current is non-linear, meaning they don’t obey Ohm’s Law in the same way. The resistance changes depending on the applied voltage or the current.
   

1. High voltages or currents: At extremely high voltages or currents, some materials might behave differently due to factors like heat or breakdown of insulating properties, causing them to deviate from the simple linear relationship of Ohm’s Law.
   

So, while Ohm’s Law is a very useful rule in electrical engineering, it has its limits and doesn’t apply universally to all materials or under all conditions. It works best for simple conductors (like metals) within certain ranges of voltage and current.