I dropped out of my clg and got TC after 1st yr of puc now can I go back join to the same clg ?

Nope! As you have take the TC, you can't go for the same college as a result, you cant appear for the repeater/supplementary examination. Now if you wish to do so then I would recommend you take admission in anyother college under the same affiliated university and as a result if there are norms by the university, then you can appear for the repeater examination.

To know more about the career in BCA visit the link below:

https://www.careers360.com/courses/bca-bachelor-of-computer-applications

I hope this answer helps. All the very best for your future endeavors!