It is not more like an interview. They just check if you have good communicating skills. Interview questions will  be mostly based on your profile like tell about yourself , or any topic your prefer. And another possibility question is that , why did yiu choose this particular branch. Be confident on your talk. tell if there are any reasons that you stand out from others. Aptitude exams consist of all basic topics where they ask a couple of logic questions. No science. More of math and logic.

hope you got answer for your question.