Yes, you can definitely do law after studying Science. The basic eligibility for law entrance is graduate.
Law degrees are of two different structures. 3 Years LL.B. and 5 Years BA/BBA LLB. You need to have a Bachelors degree for a three year LL.B. For a 5 years professional program it is an integrated course of your bachelors and LL.B.
The top entrance examinations for law are CLAT, AILET, CET.
Since you are from Science stream you can look for specialisations which revolves around technical things. There are few institutions which provide B. Tech+ LLB as well. There are many different fields where a lawyer needs to acquire both legal skills and technical skills as well.
For completion informations on eligibility, exams, subjects, specialisation etc in law check out career bank on Law -> Click here