Hello Sriram,

you have to score more than 60% aggregate in your 10+2 major in physics, chemistry, mathematics / biology , english. The Better score you do the better will be for selection in top colleges.

to Get an admission in any government college:-

take any state level or national level entrance exam and get a score below the previous year cutoff.

To do all this, you have to study smartly and have to do daily practice. Don't try to gulp everything.

Gain knowledge and understand every concept. By doing this you will remember everything for a long term and you can work on the concept in your future studies too.

Good Luck!