Question

Is Ohm's law a universal law?

Answer 1

Ohm's Law is widely used and applies to many materials, but it is not a universal law in the strictest sense. Ohm's Law states that the current passing through a conductor is directly proportional to the voltage across it and inversely proportional to its resistance, mathematically given as:

\[
V = I \cdot R
\]

where:

1. \( V \) is the voltage (in volts),
   

1. \( I \) is the current (in amperes),
   

1. \( R \) is the resistance (in ohms).
   

However, Ohm's Law only applies to ohmic materials (those that have a constant resistance regardless of the voltage or current). For materials that do not have constant resistance, such as semiconductors or non-linear materials, Ohm's Law does not hold true. In such cases, the relationship between voltage, current, and resistance is more complex and may vary with conditions like temperature, light, or voltage levels.

So, in summary:

1. Ohm's Law applies to linear and resistive materials (ohmic conductors).
   

1. It does not apply to non-linear materials, semiconductors, or superconductors (in certain conditions).
   

Therefore, while Ohm's Law is a very important and widely applicable principle in electronics, it isn't universal for all materials.