Hey. The difficulty of questions is indeed comparable, although AP tests have a significant multiple choice component. If your concepts from CBSE are clear, Physics C and Chemistry should be an absolute breeze. Nonetheless, it wouldn't hurt to attempt a few practice tests from Princeton Review or Barron's AP Books to become familiar with the format. For Calculus BC, there are a few concepts beyond CBSE like certain sequences and series, but if you haven't learnt about them earlier, prep books can help.