I've planned to do BCA course. i've completed my 12th scoring 40% in science. will i be able to get any college

No u cant but may be try in correspondence

You need to perform hard to get good colleges . Competition exams can get u admission in good colleges otherwise it is difficult for you to get admission directly in good colleges on the basis of ur 12th score. Prepare well for entrance exams

you will have to score well in the entrance and you can also take addmission in Ignou BCA.

sir If you try for good collages then you get good score in entrance test . i think some private collages is take admission on fee basis. you try n work hard