hey shubham

there is alot of things you can do after msc physics .first of all its my advice to appear in IIT JAM exam as iot will open a variety of career opportunities . coming back you can be a lab supervisor ,technioian,teacher , scientist,consultant physicist ,radiolist,scientist etc . you can get jobs in private sector as well as you can qualify government exams like ssc cgl etc

no the physics doesnot gets divide even in masters and you have to study the whole physics in 4 semesters

best wishes