Question

how can we say that curent is directly prpotinal to potential difference is carrct but in my book written that Ipropotinal to v or v prpotinal to I according to that it is carrect or nat please give a answer

Answer 1

if you will do experiment in laboratory u will
find that if applied voltage is increased current in circuit will also increase...
and after getting reading if we put it on graph we find a staight line in which current increases with increasing potential....
that's proved current is directly proportional to applied voltage putting all external parameters constant..it is also called ohm' s law....

hope this will help u