hi,

see it totally depends on your ability and interest for learning, one thing is b.tech course is professional course where b.sc is more in depth and research oriented, however you need to think if you want to learn about applied physics or applied chemistry and want to know about their application which has changed the human life, then you should go for b.tech. but if you want to research and need to learn the origins and research on any particular subjects you should go for b.sc. however you also need to choose the institution what ever course you may choose on the basis of  quality education , excellent infrastructure, experienced faculty, placement opportunity.