hello aspirant..

The difference between the jee paper 1 and 2 is that paper 1 is for the btech engineering courses and the paper 2 is for the barch architecture course. If you qualify these exams you will be eligible for the admission in nits as well other colleges accepting these exam scores respectively. you can write the jee advanced exam for iits if you qualify paper1 and if qualified in paper 1 and 2 you can write architecture advanced exam.  the expected cutoff is given below in the link,.

https://engineering.careers360.com/articles/jee-main-cutoff

all the best