State the limitations of Ohm’s law.
There are two main limitations:
(i) Temperature, (ii) Physical condition of the conductor.
It is found that the ratio V/I is mo longer constant when the temperature is not kept constant. Generally, resistance increases with the rise in the temperature of the conductor.
Physical conditions of any conductor mainly include:
(i) Its length, (ii) Its cross-sectional area, (iii) The kind of the material.
If there is no change in any of the above three conditions and also other condition like temperature remains constant, then Ohm’s law holds good, i.e., the ratio V/I remains constant.