hello altaf hussain,

YES , altaf it is possible to get admission in government colleg thorugh JEE main exam, all you need to do is register your self for the jee main exam, and as per teh score you will achieve , you admission will be done on teh basis of cut off only, if you clear teh exam with a good rank , the you will definitely get a top government and need not to worry you can pply for the jee main with 50% marks in your 12th. just study hard and do clear your jee main exam, you will get your admission done in government college for b.tech. all the very best  have a great future ahead.

Hi Atlaf. If you are from the cbse boards then it is not possible to fill the form of jee mains. Because it requires the minimum75 percentage in CBSE boards. But if you want to give jee mains exam then you can apply for the improvement exam or if you get the 75% or above then you can apply for jee mains. 

Best of luck for your future