Class 12 Computer ScienceImportant Questions for Board Exams 2025-26
16
Total Questions
8
Long Answer
8
Short Answer
Exception Handling in Python
2 questionsWhat is the difference between a syntax error and a runtime error? Give one example of each.
Write a Python program that takes two numbers as input and raises an exception if the divisor is zero. Use try-except-else-finally.
File Handling in Python
2 questionsWrite a Python function to count the number of lines in a text file.
What is the difference between 'w' and 'a' mode in file handling?
Data Handling with Pandas — Series and DataFrame
2 questionsWrite Python code to create a DataFrame from a dictionary and display only rows where marks > 80.
What are the parameters of read_csv()? Explain: filepath, sep, header, index_col.
Data Visualisation with Matplotlib
2 questionsWrite Python code to draw a bar chart showing the marks of 5 students using Matplotlib.
When would you choose a histogram over a bar chart? Give one example.
Computer Networks
2 questionsExplain the OSI model. State the function of each layer.
Distinguish between a hub and a switch. Which is more efficient and why?
Database Concepts
2 questionsWhat is a primary key? How does it differ from a candidate key and a foreign key?
State four advantages of using a DBMS over a flat file system.
Structured Query Language (SQL)
2 questionsWrite SQL queries to: (a) Create a table Student(RollNo, Name, Marks, Grade) (b) Insert a row (c) Display students with Marks > 80 ordered by Name.
What is the difference between WHERE and HAVING clause in SQL?
Society, Law and Ethics in IT
2 questionsWhat is phishing? How is it different from hacking? What are the precautions against each?
What is net neutrality? Why is it important for internet users?
Frequently Asked Questions
Which are the most important questions in Class 12 Computer Science for CBSE board exam?
All 16 questions listed here are selected based on CBSE board exam frequency and marks weightage. Prioritise long-answer (5-mark) questions first — 8 questions here — as they carry the most marks. Short-answer questions (8 here) are next. Together they cover the questions most likely to appear.
Is it enough to study only important questions for CBSE Class 12 Computer Science?
Practising these 16 important questions gets you to 70–75% marks. For 85%+, also read chapter summaries and attempt at least one full sample paper under timed conditions. Use these important questions as your minimum baseline, not your ceiling.
How should I write answers in CBSE Class 12 Computer Science board exam?
For 1-mark questions: one direct sentence — no elaboration needed. For 3-mark questions: 3 clearly numbered points, each 1–2 lines. For 5-mark questions: brief intro + 4–5 numbered points with subject-specific keywords + 1-line conclusion. CBSE examiners look for keywords in marking schemes — structure your answers around them.
How many questions come from each chapter in Class 12 Computer Science CBSE board exam?
CBSE doesn't publish a fixed chapter-wise distribution, but chapters with more important questions listed here have historically appeared more frequently in board papers. Focus extra time on chapters with 5 or more questions — those chapters consistently carry high marks.