Important Questions for CBSE Class 12 Computer Science – Chapter-Wise Guide with Concepts
Are you searching for Important Questions for CBSE Class 12 Computer Science to prepare better for your board exam? You are on the right page. CBSE Class 12 Computer Science is a practical, logic-based subject, and students who practice Python programming, SQL queries, and networking concepts regularly score higher than those who only read theory. This guide gives you a complete, chapter-wise breakdown of important topics, unit-wise weightage, and the key concepts that are asked most often in the CBSE board exam.
Every year, students look for CBSE Class 12 Computer Science important questions while revising for their final exams, since the paper combines theory, output-based questions, and programming logic. Whether it is Functions in Python, File Handling, Stack (Data Structure), Computer Networks, Database Management using SQL, or Society, Law and Ethics, this page covers the high-weightage questions that repeat every year in previous papers and CBSE sample papers.
Computer Science rewards regular coding practice more than one-time reading. By focusing on important questions for Class 12 Computer Science, students save revision time and target the units that carry maximum marks. This guide also includes simple concept tables for quick revision before the exam. Keep reading to know which chapters need more attention and how to score full marks in CBSE Class 12 Computer Science.
CBSE Class 12 Computer-Science Important Questions – All Chapters PDF
Why Practicing Important Questions Helps in Computer Science
The CBSE Class 12 Computer Science paper includes a mix of theory questions, output-prediction questions, and code-writing questions based on Python and SQL. Practising important questions for Class 12 Computer Science helps students understand common question patterns, avoid syntax errors in coding questions, and manage time better during the exam, since tracing program output and writing correct SQL queries both require careful, step-by-step practice.
Unit-Wise Weightage in CBSE Class 12 Computer Science
Knowing the marks distribution helps students plan their last few weeks of revision more effectively.
Unit / Chapters Covered | Approx. Marks |
Computational Thinking and Programming – Functions, File Handling, Stack, Data Structures | 45 |
Computer Networks | 13 |
Database Management and SQL | 25 |
Society, Law and Ethics | 5 |
Practical – Lab Work, Project, Viva | 30 |
Functions in Python – Important Questions
This chapter tests a student's understanding of user-defined functions, parameter passing, default arguments, and the difference between actual and formal parameters. Common important questions ask students to write a function-based program, predict the output of a code involving global and local variables, or explain the difference between call by value and call by reference behaviour in Python. Before Solving the Important Questions one must solve NCERT solutions with the help of NCERT solutions for Class 12.
Concept | Key Point |
Function Definition | def function_name(parameters): |
Default Argument | def func(a, b=10): — b takes default value if not passed |
Global Keyword | Used inside a function to modify a global variable |
Return Statement | Sends a value back to the calling function |
Recursion | A function calling itself to solve a smaller sub-problem |
File Handling in Python – Important Questions
File Handling questions ask students to open, read, write, or append data to text files and binary/CSV files. Important questions frequently test file modes, use of the with statement, and reading/writing data using the pickle and csv modules, along with searching or counting specific data inside a file.
File Mode | Meaning |
'r' | Read mode (file must exist) |
'w' | Write mode (creates new/overwrites existing file) |
'a' | Append mode (adds data at the end) |
'r+' | Read and Write mode |
'rb' / 'wb' | Read/Write mode for binary files |
Stack (Data Structure) using List – Important Questions
This chapter tests the Last In First Out (LIFO) concept implemented using a Python list. Important questions usually ask students to write functions for push and pop operations, check if the stack is empty, or implement a stack-based program such as evaluating balanced parentheses or reversing elements.
Operation | Python Implementation |
Push | stack.append(item) |
Pop | stack.pop() |
Peek (Top Element) | stack[-1] |
Check Empty Stack | if len(stack) == 0 |
Computer Networks – Important Questions
Computer Networks questions cover network types, topologies, transmission media, and networking devices. Important questions ask students to differentiate between LAN, MAN, and WAN, identify the correct network topology for a given scenario, and explain the role of devices like switches, routers, and repeaters.
Concept | Explanation |
LAN | Network within a small area like a building or campus |
MAN | Network spanning a city |
WAN | Network spanning a country or across countries |
Star Topology | All nodes connected to a central hub/switch |
Router | Connects different networks and directs data packets |
Switch | Connects devices within the same network |
Database Management and SQL – Important Questions
This is one of the highest-weightage chapters, testing SQL commands related to creating tables, inserting data, and retrieving data using conditions, grouping, and joins. Important questions commonly ask students to write SQL queries using WHERE, GROUP BY, HAVING, ORDER BY, and simple JOIN operations, along with identifying primary keys, candidate keys, and foreign keys.
SQL Clause / Command | Purpose |
SELECT | Retrieves data from a table |
WHERE | Filters rows based on a condition |
GROUP BY | Groups rows sharing a common value |
HAVING | Filters groups (used with GROUP BY) |
ORDER BY | Sorts the result in ascending/descending order |
JOIN | Combines rows from two or more tables |
Keys and Constraints in SQL – Important Questions
Important questions from this section ask students to identify the correct type of key for a given table structure and understand data integrity rules used in relational databases.
Key Type | Description |
Primary Key | Uniquely identifies each record in a table |
Candidate Key | An attribute (or set) that can qualify as a primary key |
Foreign Key | A field that links to the primary key of another table |
Alternate Key | A candidate key not chosen as the primary key |
Society, Law and Ethics – Important Questions
This unit is theory-based and covers cyber safety, digital footprints, intellectual property rights, and cybercrime. Important questions frequently ask students to define or differentiate between terms such as phishing, plagiarism, copyright, and cyberbullying, and to suggest safety measures for responsible use of the internet and social media.
Term | Meaning |
Phishing | Fraudulent attempt to obtain sensitive information by pretending to be a trusted source |
Plagiarism | Presenting someone else's work as one's own without credit |
Digital Footprint | The trail of data a person leaves while using the internet |
Cyberbullying | Using digital platforms to harass or intimidate someone |
Preparation Tips for CBSE Class 12 Computer Science
Practice writing Python programs by hand instead of only reading code, since board exams require handwritten code without an IDE's auto-correction. Revise all SQL query formats thoroughly, as this section offers direct and scoring marks if syntax is correct. Solve previous years' CBSE Class 12 Computer Science question papers to understand common output-based and error-correction questions, and keep a quick-reference sheet of Python string, list, and dictionary functions handy during revision.
Final Words
Preparing with important questions for CBSE Class 12 Computer Science helps students focus on high-weightage areas like Python Functions, File Handling, and SQL instead of spreading revision time equally across the syllabus. Use the chapter-wise breakdown, concept tables, and weightage list above to plan your final revision. For more chapter-wise notes and subject guides for CBSE Class 12, keep following MyClass24.