if we select science after puc 2nd can we go to engeeneering field
Yes Science in PUC is similar to choosing class Science stream in class 12th. So Yes you can go into engineering programmes but you need to give the required state or national competitive exams like JEE or college exams like for Narsee Monjee or Symbiosis.
You cant get into an engineering college just by the PUC score. You need to give the competitive exams.