Saiprasad,
Depending upon the movements of large cap stocks , Nifty Index Moves.If you have a view that markets are going to move Higher/Lower. you can trade in top 10 or 15 large cap stocks.
Use this LINK and select
Method of Computation, Base Date & Value, Criteria for Selection of Stocks
scroll down little bit you will find file " Download Industry-wise Market Capitalisation, Weightage, Beta etc. (.csv)" ,
Once you have this file you can check out weightage of each stock on the Nifty with beta.