What is the the limitations of …

Limitations of Ohm's Law:
Ohm's law is not a fundamental law of nature. There are a number of commonly used circuit elements which do not obey this law called Non – Ohmic conductors.
Non – Ohmic conductors have one or more of the following properties:
1. Potential difference (V) depends on current (I) non-linearly.
2. The relation between V and I is non-unique, that is, for the same current I, there is more than one value of voltage V.
3. The relationship between V and I depends on the sign of V f or the same absolute value of V. 

The resistance of a material changes when the temperature changes. So when the resistance changes, the ratio of the voltage across the resistor and the current passing through it will not be a constant. We will not get the same numbers always. Non – linear elements and unilateral networks do not support ohm's law.