Question

state ohm's law . how can it be verified experimentally

Answer 1

According to Ohm's law,
If a current through a wire when potential difference across the ends of the wire is V,the resistance offered by the wire to the flow of current is the ratio of potential difference across it to the current flowing

R=V/I or V=I R

Answer 2

the current flowing through a conductor is directly proportional to the potential difference at constant temperature.
we make a circuit -->
to start we press the switch , and current flows in the circuit. we note the respective readings of the ammeter and voltmeter. we increase the current step by step and the value of I and V in all cases.
conclusion -->
we plot a graph between V and I and observe that the graph is a straight line. so we say ratio of V/I is constant . hence Ohm 's law proved