Hello,

The main difference is that BCA graduate is armed with knowledge of scripting and   software programming like java, C++ etc and is of three year under graduate course . A B.Tech graduate has knowledge of both hard wear and soft ware and is four year under graduate course

Hey,
BCA or Bachelor  of Computer Applications is a three year long undergraduate programme that equips a students with the knowledge of computer applications. After completing BCA,one can work in IT sector as computer programmer,computer systems analyst etcetra.
On the other hand, B.Tech is a four year long undergraduate programme in various courses like Computer Science,Electrical,Civil etcetra.
Hope this helps.
Good luck.