The RTI Act has not prescribed any ceiling on the number of questions or the number of topics in an application. Whether the PIO provides information or rejects the request, depends on the nature of questions that are asked.
I would suggest you to go through the FAQ section and the online RTI Act section in our portal to get yourself acquainted with RTI. Please also browse through the various discussion forums, wherein you will get a lot of valuable information.
If you have got a specific query, please furnish the full details of the same and the experienced members of our portal will be happy to assist you.