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Knowing the syllabus is half the preparation. The other half is knowing how the paper is built: how many questions, which units carry the marks, and where the time goes. For CBSE Class 12 computer science (subject code 083), all of this is public. This post reads the official 2026-27 sample paper and curriculum, maps the marks to units, and turns them into a timing plan.
How is the paper divided into sections?
The 2026-27 sample question paper is a 3-hour, 70-mark paper with 37 compulsory questions, some with internal choice:
Section A: 21 questions of 1 mark each (21 marks). Multiple choice, predict-the-output, fill in the blank, and two assertion-reason questions.
Section B: 7 questions of 2 marks (14 marks). Short answers: correct a buggy program, write a small function, predict output, write SQL commands.
Section C: 3 questions of 3 marks (9 marks). Text file functions, stack push and pop, list or tuple processing.
Section D: 4 questions of 4 marks (16 marks). SQL queries on given tables, a CSV file task, Python-MySQL connectivity.
Section E: 2 questions of 5 marks (10 marks). A binary file task and a network design case study.
Every page of the sample paper carries the note that there is no change in the question paper design and assessment pattern for 2026-27. All programming answers must be in Python, and for multiple-choice questions you should write the text of the correct option, not just the letter.
Which units carry the marks?
The 2026-27 curriculum splits the 70 theory marks into three units: Computational Thinking and Programming 2 (40), Computer Networks (10) and Database Management (20). Practicals carry another 30: a lab test (8 for a Python program, 4 for SQL queries), a report file (7), a project (8) and a viva (3).
We matched each question in the sample paper to its unit. The totals land exactly on the curriculum's numbers:
Networks, 10 marks: questions 8, 12 and 17 (1 each), 28 (2) and the case study in 37 (5).
Databases, 20 marks: six 1-mark questions (4, 9, 13, 15, 19, 21), question 27 (2), and questions 32, 34 and 35 (4 each). Question 35 is Python-MySQL connectivity, which sits in the database unit.
Python, 40 marks: everything else, including question 36 on binary files (5).
So the two 5-mark questions come from different units: one Python, one networks. You cannot skip either unit and still reach Section E safely.
Worked example: a timing plan
You have 180 minutes for 70 marks. Keep 15 minutes at the end to check SQL syntax and output answers. That leaves 165 minutes, or about 2.4 minutes per mark (165 ÷ 70 = 2.36).
Section A, 21 marks: about 50 minutes.
Section B, 14 marks: about 33 minutes.
Section C, 9 marks: about 21 minutes.
Section D, 16 marks: about 37 minutes.
Section E, 10 marks: about 24 minutes.
That adds up to 165. In practice, many 1-mark multiple-choice questions take under a minute, so bank that time for Sections D and E, where writing a full function or five SQL queries takes longer. If a Section A output question is taking more than three minutes, mark it, move on and come back.
What does each section reward?
Section A: precision. Question 10 asks for print(25+10013/5), and the marking scheme answer is 45.0. The float matters. Our guide to predict-the-output questions gives a tracing method.
Section B: clean, correct code. Question 23 asks you to fix syntax and logic errors and underline each correction; underlining is part of the instruction.
Sections C and E (files and stacks): complete functions. Open the file with the right mode, loop through it, close it or use with.
Section D (SQL): exact syntax. Distinct, GROUP BY with HAVING, LIKE patterns and joins all appear. See our SQL guide for CBSE.
Network case study: reasoning from the data. Place the server in the block with the most computers, and justify a repeater by distance. Our computer networks guide covers the devices and topologies.
The official marking scheme shows how marks split inside answers, often half a mark per correct step, so partial work earns credit.
Why practise with full papers?
Doing full papers is retrieval practice, not just checking. In a classic study, Roediger and Karpicke (2006) found that students who took practice tests remembered more after two days and a week than students who spent the same time restudying, even though restudying made students feel more confident.
A six-week routine
Weeks 1 to 2: one unit per week from the sample paper. Redo every question in that unit without notes.
Weeks 3 to 4: one full timed paper per week, using the plan above. Mark it with the official scheme.
Weeks 5 to 6: two timed papers per week, plus a list of every mark lost and why.
For the SQL and file-handling questions where your method goes wrong, the Fermi Problem Library has a step-by-step solver that explains the reasoning rather than printing an answer.
This week, download the 2026-27 sample paper and do Section A alone in 50 minutes.
