State and Prove ohm 's Law ?

Explanation

Ohm .s Law states that the current (I) flowing through a cnonductor is directly proportional to the potential differnce (V) applied across the ends of the conductor provided physical conditions of the conductor such as temperature mechanical strain etc . are kept constant .
i.e . `I prop V`
or `VpropI`
`(V)/(I)=R`
`V=RI`
we know that ,
`v_(d)=(eEtau)/(m)`
But `E=(V)/(l)` `u_(d)=(eVtau)/(ml)` .... (2)
Al so , `I=A n e v_(d)`
`I=A n e xx(eVtau)/(m.l) " " ["Using equation"(2)]`
`I=(A n e^(2)Vtau)/(ml)`
`I=((A n e^(2)tau)/(ml))V`
`(I)/(V)=(A n e^(2)tau)/(ml)`
`(V)/(I)=(m)/(n e^(2)tau)(l)/(A)`
`(V)/(I)=rho(l)/(A) " " ["because" rho=(m)/(n e^(2)tau)]`
`(V)/(I)=R`
where , R= a constant for a conductor for a given value of n , l . A and at a given temperature . It is known as the electrical resistance of the conductor .
Thus V=IR
This is ohm .s LAw .