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Some concept are not clear

As I will go in 2nd year

@Mudit
This is very nice to know that you are so serious about the same. But as you are in 1st year only, so I would suggest you to start your preparation in 3rd year because that the ideal time for Gate preparation. And focus on your B.tech syllabus as of now and clear all your concepts as this will be helping you in your Gate studies.

You can consider below coaching names -
Ace Academy
Gate Academy
Made Easy
Gate Forum.

Hope ths helps!!!

Till today,I am planning for online coaching,but I have clear concept on 12th mechanics,As I am going to 2nd year in August 2017

Ok then, you can consider the names which I have provided above. But again I would say it would be better to start your preparation in 3rd year. Rest your choice.

All the very best!!!