For last 5 years papers of CBSE Class 12 you could visit http://www.cbsewizard.com/cbse-class-xii/previous-year-papers/ they list subject-wise papers on their website in pdf form that are easy to access.
Where Can I Get Last 5 Years CBSE Class XII Question Papers?
Go to any book shop n buy mohan's sample paper .cost rs.25 only