ISC 2025 Computer Science Improvement Examination Question Paper for Class 12

About this paper

This is ISC Class 12 Computer Science Paper 1 (Theory), code 868A-IE, from the 2025 Improvement Examination. It carries 70 marks and three hours, plus fifteen minutes to read the paper. There are 11 questions on 15 printed pages. Part I, worth 20 marks, is compulsory and uses multiple-choice and assertion–reason items. Part II, worth 50 marks, has three sections, and any two questions are taken from each. Section A includes a free-delivery truth table, Karnaugh maps and an octal encoder. Section B is Java: mighty numbers, joining two arrays from the end, and palindrome words whose length is prime. Section C is a circular queue, train tickets with a group discount, a linked list and a binary tree. This copy has the questions only.

Exam

ISC Class 12

Subject

Computer Science

Year

2025

Paper code

868A-IE

Maximum marks

70

Time allowed

3 hours + 15 min reading

Questions

11

Pages

16

Answers included

No, questions only

Paper pattern

• Part I

  20 marks

  Questions 1 and 2, all compulsory: multiple-choice and assertion–reason items, a postfix conversion and two Java methods

• Section A

  20 marks

  Questions 3–5, ten marks each; answer any two. A free-delivery truth table reduced with NAND gates, Karnaugh maps and an octal encoder

• Section B

  20 marks

  Questions 6–8, ten marks each; answer any two. Java classes for mighty numbers, joining two arrays and palprime words

• Section C

  10 marks

  Questions 9–11, five marks each; answer any two. A circular queue, train-ticket inheritance, a linked list and a binary tree

Topics covered

• Boolean algebra and duality
• Propositional logic
• Karnaugh maps
• Encoders and half adders
• Recursion and Big O notation
• Arrays
• Strings and palindromes
• Inheritance
• Circular queues
• Linked lists and binary trees

Questions from this paper

1. Convert the infix expression (A * B ^ C) + (D * E), where B ^ C means B to the power C, to postfix form.
2. A food-delivery app gives free home delivery when the order is above ₹1000 and paid by UPI, or the food comes from a partner restaurant and is paid by UPI, or it is the customer's first order and is above ₹1000. Write the SOP expression for D(A, U, P, F).
3. Class Mighty appends the eventual digit-sum of each integer to the other. The eventual digit-sum of 235 is 1, and the eventual digit-sum of 106 is 7.
4. Class Palprime displays words that are palindromes of prime length. From MY MOM POSSESSES A GOOD LEVEL OF KNOWLEDGE IN MALAYALAM, the words are MOM and LEVEL.
5. Class MerryGoRound is a circular queue. Specify add and remove, and state the principle on which this entity works.
6. Subclass Booking charges the ticket price times the number of passengers, and applies a group discount of 10% when there are more than five passengers.