Dear aspirant, The NEET 2020 question paper will comprise 45 questions from Physics, 45 questions from Chemistry and 90 questions from Biology. The weightage of chapters is same as the previous year. Generally around 40% Weightage is given to class 11th chapters while rest all comprises of questions from class 12th.You can check this link for chapter wise Weightage of all the three subjects.

Here's the link

All the best

Hope this helps