State Ohm's law. How can it be verified experimentally? Does it hold good under all conditions? Comment.

(N/A) Ohm's law states that the current $I$ flowing through a conductor is directly proportional to the potential difference $V$ across its ends,provided the temperature and other physical conditions remain constant. Mathematically,$V \propto I$ or $V = IR$,where $R$ is the resistance of the conductor.
Experimental Verification:
$1$. Set up a circuit consisting of a resistor,an ammeter in series,a voltmeter in parallel across the resistor,a battery,and a rheostat.
$2$. Adjust the rheostat to change the current in the circuit and record the corresponding readings of the ammeter $(I)$ and voltmeter $(V)$.
$3$. Plot a graph of $V$ (y-axis) versus $I$ (x-axis). $A$ straight line passing through the origin confirms Ohm's law.
Limitations:
Ohm's law does not hold under all conditions. It is not applicable to non-ohmic devices like diodes,transistors,and vacuum tubes,where the $V-I$ relationship is non-linear. Additionally,for ohmic conductors,if the temperature changes significantly due to heating,the resistance $R$ changes,and the law may not hold strictly.