Hi Shivani,

BA is a three year full time graduation course divided into six semesters. Minimum eligibility for pursuing BA is 10+2 from any recognized school or Institute.
Best colleges for BA are:-
1. St. Xaviers college, Mumbai
2. Hansraj college, Delhi
3. Hindu College, Delhi
4. Miranda College,  Delhi

There are 5 subjects in total.
If you want to do BA in pol science you have to choose  subject POL SCIENCE and Two more subjects of your choice or interest say Economics, sociology, history, geography etc.
And the other two subjects are the compulsory subjects which you  have to take.

Hope it helps:)