Ohms law states that current flowing between two points in a conductor is directly proportional to the potential difference between the two points provided temperature is kept constant.
I  is directly proportional to  V
V/IR (constant)the constant is resistance.

limitations of ohms law:
It is valid for metal conductors provided temperature and other physical conditions remain constant. the resistance of the material changes with temperature. it is not applicable for a gaseous conductor. it is not applicable to semi conducters like germanium and silicon.