Hello Shubham.

As per current trends cut off of jee mains vary every year. It's maximum fluctuation is from 100-120 for general candidates.

But by just qualifying it you can only get a private college.

I suggest you to study hard and score 170+ to get admission in some NIT.

Ok

Good luck.

For a good college for Btech , you should get above 100 marks . See if you get good marks in JEE mains and in your 12th std pcm (physics , chemistry and maths ) ,ultimately your percentile will be good , so if your percentile is good , then your chance to get admission in top colleges will be good . If you quaified for JEE advanced and if you are in top 20 percentile then you may get admission in IIT's too . 

Hello..

It is a very nice question, but the answer is very vast. It depends upon what type of engineering college you want to get admitted in and what are your preference.

For example 120 marks can also fetch you good college and also 355 marks.

But surely you need to qualify.

Hope this is helpful