I have completed BA in Art but I am Interested to do Online B.tech, am I eligible for that ??

The eligibility criteria for a B.Tech program is that the students must have completed their 12th class with the subjects: Physics, Chemistry, and Mathematics. unless you have these subjects in your 12th class you can not pursue an online B.Tech.

Even if you have Maths as a subject in your BA, then also you can not apply for a B.Tech program.

To pursue a B.Tech program, candidates must have studied Mathematics and Physics in 12th standard or Polytechnic diploma in engineering. 

Online B.Tech is invalid in India as per the judgment of the Supreme Court. Even Part-time B.tech and Distance B.Tech programs aren’t valid. It means UGC and AICTE don’t approve these programs. However, there are B.Tech Flexible Timing program is meant for working professionals. The program is designed for working professionals after a polytechnic diploma can earn a graduation degree in engineering to upgrade their knowledge and they must have working experience in the relevant field. 

Those who apply for the B.Tech Flexible Timing program are directly promoted to the second year of the program so the duration of the B.Tech program is 3 years for them because of their previous knowledge and working experience.