Hello Bhimanna,

Do not worry, there is no problem if you have chosen Physics, Chemistry, Maths and Biology as your class 12th subjects and haven't chosen Computer Science. No engineering college in India requires you to choose Computer Science as a subject in class 12th. All of them consider your PCM marks as well as aggregate marks before giving admission irrespective of the branch you want to take admission in. The only problem that you might face is that for you coding will be completely new in B.Tech while others who have chosen Computer Science in class 12th would be aware of coding basics.

Hello...
There is no problem,you can take computer science Engineering in b.tech.For Engineering Physics,Maths,and  Chemistry are compulsory in course.Therefore you are eligible . Biology will not matter this.Biology can be treated as fifth subject .
Hope it helps you.
Good luck.