ISC 2015 Computer Science Question Paper for Class 12

About this paper

This is ISC Class 12 Computer Science Paper 1 (Theory), code 868A, from the 2015 board examination. Three hours are allowed, with an extra fifteen minutes to read the paper. Part I, Questions 1 to 3, is compulsory and covers Boolean algebra, a recursive Java method and an Armstrong-number method that does not use the modulus operator. From Part II, candidates answer seven questions: three from Section A, two from Section B and two from Section C. Section A is Karnaugh maps, encoders, multiplexers and a half adder. Sections B and C must be written in Java and cover classes, a character stack called WordPile, inheritance, a linked list and a binary tree. This copy has the questions only.

Exam

ISC Class 12

Subject

Computer Science

Year

2015

Paper code

868A

Time allowed

3 hours + 15 min reading

Questions

13

Pages

10

Answers included

No, questions only

Paper pattern

• Part I

  Questions 1–3, all compulsory: Boolean algebra, recursion and an Armstrong-number method

• Section A

  Questions 4–7; answer any three. Karnaugh maps, a railway-travel truth table, an encoder, a multiplexer and a half adder

• Section B

  Questions 8–10; answer any two. Java classes for binary search, merging two integers and counting words and consonants

• Section C

  Questions 11–13; answer any two. A character stack, inheritance for a circle, a linked list and a binary tree

Topics covered

• Boolean algebra and De Morgan's laws
• Logic gates and circuits
• Karnaugh maps
• Encoders and multiplexers
• Half adder
• Computational complexity
• Infix to postfix conversion
• Arrays and binary search
• Recursion
• Strings
• Stacks
• Inheritance, linked lists and binary trees

Questions from this paper

1. Simplify (A + C)·(A + A·D) + A·C + C.
2. Verify with a truth table that P ∨ (~P ∧ Q) = P ∨ Q.
3. State De Morgan's law and verify it using a truth table.
4. Convert the infix expression X + (Y − Z) + ((W + E) * F) / J into postfix form.
5. Class Admission stores 100 admission numbers in ascending order. Write a recursive binary search that returns 1 if a given number is found and −1 otherwise.
6. Class Merger joins two positive integers. If the numbers are 23 and 764, the merged number is 23764.