hi how i am prepared for aiims g.k nd mental ability question can anybody suggest me a book for that

For this section you should read newspapers watch news channel.  Focus on India and the Indian national movement. As always, the past papers are very important and more so because they're the only clue to localize and predict questions to some extent. There's no specific book for reading entrance based GK from. What you can do is to read up on and around the topics asked in past papers.

Good Luck!!