Is it necessary to give JEE mains exam 2020 just before or just after the board exam 2020 ?
Ever since last year NTA is conducting JEE mains twice a year. Out of the two; they consider the best of your result. Even if you fail to qualify or not appear in the April shift the first one will be count ; while considering just before board exam as the Jan shift exam and just after board exam as the April shift.
Same goes for the April shift. If you don't give the January exam or fail to score good there; but end up scoring well in the April shift, the percentile from April would be considered.
So, it's affirmative that it's not necessary or compulsory to appear in any of the 2 exams. You can attend either one of them.
But you should be happy they are providing two chances; you should be prepared to give your best in both of them!
Hope this helps and best of luck!
Since you can attempt JEE mains twice, you can give once before your boards and one after your boards.
Even if you score less in the one before your boards, you will have a chance to analyse where you are strong and where you are lacking and improve yourself in the second attempt.
You would have completed boards by the time of second attempt, hence already studying all the syllabus once, because mains and your boards syllabi largely overlap giving you an edge of revision and if you would have attempted previously, experience of it adds.