Hello student,

National testing agency each and every year conducts JEE MAIN and advance examination to provide candidates in in engineering colleges including NIT with main examination, and by passing advance examination candidates can take admission in IITs.

The basic eligibility criteria of JEE main 2022 examination is just that you should pass your ten plus two level in 2020 or 2021 or be appearing on 2022 from any recognised Central and state board, or any public or boarding University examination etc.

Now in this situation in the previous year there was no no minimum percentage required to be eligible for examination. 2022 notification has not come yet that's why it is quite difficult to say about that.

But overall if your friend wants to take PCM instead of PCB, he  have to take admission again in 11th , and then after 2 years as he will pass his 10 plus two level with PCM you will be eligible for JEE main examination. You may go through this link below to know more about eligibility criteria

https://engineering.careers360.com/articles/jee-main-eligibility-criteria

If your friend is preparing for JEE main examination I can suggest you to have jeemaim knockout preparation course which includes top class video lectures study materials doubt solving seasons artificial intelligence based personalised report and lots of many more. You may click on the link below to know more

https://learn.careers360.com/engineering/jee-main-preparation-material/