The syllabus for msc entrance exams is generally released by the organising college or university well in advance on their official website. Candidates are recommended to prepare each and every topic mentioned.Be thorough with your bsc syllabus and have a clear idea about each and every concept.Many entrances such as IIT JAM ,TIFR,JNU also ask questions from maths chem and physics too.So for scoring a good score i would suggest you to go through 10+2 syllabus.Questions from these part are very easy and bases on mostly 11th and 12th basics.There are many books available for entrances also you can join coaching classes if you wish to.Solve the previous years question papers to get an idea.Some entrances are followed by interview in which they check your basic concepts and how well you can apply them,basics from others subjects such as chemistry also asked like normality molarity types.

Plan accordingly be thorough in whatever you are preparing and clear the entrance with flying colors.

Hope this helps you

All the best!