Hello Sayam, 

To your preparation to 11th std entrance exam you have not mentioned specifically for which Institute you want to apply for , so if you want to prepare for engineering and want to get into a good institution like fiitjee, you should make your base strong in physics, chemistry and mathematics. 

On the contrary if you want to join any institution focused on medical preparation you should prepare well for Physics ,Chemistry,  Biology well. 

Hence as you haven't mentioned the Institute i am sharing with you the model test papers link for 11th entrance exam to get into fiitjee. 

It's www.fiitjee.com

I hope this helps, you can further ask for more queries. All the best.