I want to prepare for the competetive exams .i usually face problem in reading.

Hey Harsha, if you are trying to concentrate on study then don't waste your time here. Seriously, I think mylot is not a place for students who are preparing for competitive exams. Always try to understand the basic concepts first for whatever things you are studying. Go for basic and most authentic books. Then slowly you will find yourself in good standing. Good Luck.