ISC 2020 Computer Science Question Paper for Class 12

About this paper

This is ISC Class 12 Computer Science Paper 1 (Theory) from the 2020 board examination, with a worked answer written under each question. It carries 70 marks and three hours, plus fifteen minutes to read the paper. Part I is compulsory and worth 20 marks. Part II is worth 50 marks, and candidates answer two questions from each of Sections A, B and C. Section A is Karnaugh maps, an octal-to-binary encoder and a full adder. Section B is Java classes for a day-number calendar, binary search and mixing two words. Section C covers a circular queue, the volume of a cylinder through inheritance, a linked list and a binary tree. The written answers show one way of working each question.

Exam

ISC Class 12

Subject

Computer Science

Year

2020

Maximum marks

70

Time allowed

3 hours + 15 min reading

Questions

12

Pages

10

Answers included

Yes

Paper pattern

• Part I

  20 marks

  Questions 1–3, all compulsory: Boolean algebra, data structures and a recursive dry run, each with a written answer

• Section A

  20 marks

  Questions 4–6, ten marks each; answer any two. Karnaugh maps, an octal encoder, a full adder and a power-load truth table

• Section B

  20 marks

  Questions 7–9, ten marks each; answer any two. Java classes for a day-number date, binary search and mixing two words

• Section C

  10 marks

  Questions 10–12; answer any two. A circular queue, cylinder volume by inheritance, a linked list and a binary tree

Topics covered

• Boolean algebra
• Karnaugh maps
• Encoders and full adders
• Propositional logic
• Binary trees and linked lists
• Infix to prefix conversion
• Bubble sort complexity
• Recursion
• Binary search
• Strings
• Circular queues
• Inheritance and interfaces

Questions from this paper

1. State the properties of zero in Boolean algebra.
2. Find the complement of F(P, Q, R) = P + (Q′·R) using De Morgan's law.
3. Convert the infix expression (X + Y) / (Z * W / V) to prefix form.
4. What does check return for n = 25 and for n = 10?
5. Class Convert finds the date for a day number in a given year. Day number 64 in 2020 is 4 March 2020, because 31 + 29 + 4 = 64.
6. Class Mix interleaves two words character by character. JUMP and STROLL become JSUTMRPOLL.