Yes, most surely one can take up the Information Science course as an undergraduate course if they belong to a PCMB background; quite a few universities offer Information Science courses open to students from different backgrounds, even PCMB students.

For example, while it is good to have a sound knowledge of Mathematics and Science, it is not necessarily a prerequisite to get into any course. Usually, universities offer bridging courses or introductory modules that one may have to attend in case one does not have much of a background in computer science or information technology.

Preparation for Information Science Course Entrance Exam:

Familiarize yourself with the Syllabus: Look through the syllabus for the entrance exam you are targeting. From here, you will know where to concentrate.

Update Yourself with Basic Computer Science Concepts: For those who haven't had in-depth academic training, take some time and get familiar with programming basics, data structures, and basic algorithms.

Practice Logical Reasoning and Problem-Solving: This is the skill one needs in order to crack information science. Practice riddles, puzzles, and logical reasoning.

Update with Current Trends: Keep track of the latest trends and developments in this field.

Advice: Refer teachers or mentors for proper advice or visit online resources for support.

Practice Previous Year's Papers: This will help you understand how the exam pattern and time management goes.

It will, therefore, be possible to score well in entrance exams for Information Science courses if the above tips are followed religiously along with consistent efforts.