Computer Science

According to the eligibility criteria for the CSIR NET exam, candidates must have a master's degree or its equivalent in the relevant subject with a minimum of 55% marks (50% for SC/ST/OBC-NCL/PwD candidates). Since you are pursuing an M.Sc. In Applied Mathematics, you may be eligible to appear for the CSIR NET exam in the Mathematical Sciences stream. However, if you want to appear for the CSIR NET exam in the Computer Science stream, you will need to have a master's degree or its equivalent in Computer Science or a related discipline such as Electronics & Communication Engineering, Information Science, or Information Technology with a minimum of 55% marks (50% for SC/ST/OBC-NCL/PwD candidates). Therefore, if you have completed your M.Sc. In Applied Mathematics and wish to appear for the CSIR NET exam in the Computer Science stream, you may need to pursue an additional qualification such as a Master's in Computer Science or a related field to meet the eligibility criteria.

Considering that I have given this exam and currently pursuing Masters in CS from FC Pune, I am sort of qualified to answer this. So, this exam consists of two sections, Aptitude
Computer Science
In aptitude section, the questions are based on general 10th level math and mental ability, for example, direction-based, or sequence-based. These can be tackled by anyone, in general. But, if you fell that you are too weak in mathematics or something like that, then, I would suggest you to go through some Quantitative Aptitude book, like, Quantitative Aptitude by R. S. Aggarwal or any other which you might prefer. Do not solve the whole book. You need not do SSC level preparation for it. Go through the kind of questions and look through the basic concepts, that is all that is required or expected of you. Just be a little aware with numbers, that is all. This section does not require specialisation of any kind, they are easy, to be frank.