Hello aspirant !

As you have mentioned that you have got 300 marks and you are from obc category ,so by analysing marks Vs rank 

Score.                 Rank .  

300-349.           25000-16001

So your rank will be near about 25000 so now we are analysing IET Lucknow 2018 cutoff as it has not declared its final cutoff of 2019 so with the help of previous year cutoff you can have a clear idea

2018 cutoff for OBC category

Branch.                                         Closing rank 

chemical engineering.                  4840

Civil engineering.                           3366

CS Engineeing.                               1250

Electrical engineering.                  2741

EC engineering.                              2075

IT                                                      1673

Mechanical engineering.              2736

since your obtained rank is very much more than the min cutoff of IET LUCKNOW so you can not expect your admission in any branch of this collge

Hope it helps