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ISC Class XII Board Examination

ISC Computer Science (Paper 1 — Theory) — Specimen Question Paper 2025

Specimen2025Subject code 868
Open source paper at static.collegedekho.com (opens in a new tab)
Board
ISC Class XII Board Examination
Class
Class 12
Subject
Computer Science
Year
2025
Total marks
Not verified
Duration
Not verified

Verification and rights

Checked against a named, citable source that is recorded with the record.

Imported specimen paper from CollegeDekho (mirror of CISCE PDF) on 2026-08-29.

Questions in this paper

  1. 1((i))The compliment of the Boolean expression Aꞌ • (B • Cꞌ + Bꞌ • C)1 mark
  2. 1((ii))Given below are two statements marked Assertion and Reason. Read the two
    statements carefully and choose the correct option.
    Assertion: Recursion utilises more memory as compared to iteration.
    Reason: Time complexity of recursion is higher due to the overhead of
    maintaining the function call stack.    1 mark
  3. 1((iii))According to the Principle of duality, the Boolean equation
    (Aꞌ + B) • (1 + B) = Aꞌ + B will be equivalent to:    1 mark
  4. 1((vi))Study the given propositions and the statements marked Assertion and Reason that
    follow it. Choose the correct option on the basis of your analysis.
    p = I am a triangle
    q = I am a three-sided polygon
    s1 = p → q
    s2 = q → p
    Assertion: s2 is converse of s1
    Reason: Three-sided polygon must be a triangle.    1 mark
  5. 1((vii))Given below are two statements marked Assertion and Reason. Read the two
    statements carefully and choose the correct option.
    Assertion: In Java, the String class is used to create and manipulate strings, and it
    is immutable.
    Reason : Immutability ensures that once a String object is created, its value cannot
    be changed.    1 mark
  6. 1((viii))Consider the following statement written in class Circle where pi is its data
    member.
    static final double pi = 3.142;
    Which of the following statements are valid for pi?
    I. It contains a common value for all objects class Circle.
    II. Its value is non-changeable.
    III. At a time two access modifiers, static and final, cannot be applied to a single
    data member pi.    1 mark
  7. 1((ix))For Big O notation, state the difference between O(n) and O(n2).1 mark
  8. 1((x))A full adder needs five gates and those are 3 AND gates, 1 OR gate and 1 XOR
    gate. When a full adder is constructed using 2 half adders, it also requires 5 gates.
    State the names along with the quantity those gates.
    --------------------------------------------------------------------------------------------------------------------------------    1 mark
  9. 2((i))Convert the following infix notation to prefix form.
    (A–B)/C*(D+E)    2 marks
  10. 2((ii))A matrix M[-6….10, 4…15] is stored in the memory with each element requiring
    4 bytes of storage. If the base address is 1025, find the address of M when
    the matrix is stored in column major wise.    2 marks
  11. 2((iv))The following is a function of class Armstrong. This recursive function calculates
    and returns the sum of the cubes of all the digits of num, where num is an integer
    data member of the class Armstrong.
    [A number is said to be Armstrong if the sum of the cubes of all its digits is equal
    to the original number].
    There are some places in the code marked by ?1?, ?2?,?3? which may be replaced
    by a statement/expression so, that the function works properly.
    public int sumOfPowers(int num)
    {
    if (num == 0)
    return ?1?;
    int digit = ?2?;
    return (int) Math.pow(digit, 3) + ?3?;
    }
    (a) What is the expression or statement at ?1?
    (b) What is the expression or statement at ?2?
    (c) What is the expression or statement at ?3?
    ----------------------------------------------------------------------------------------------------------------------------------
    PART II– 50 MARKS
    Answer six questions in this part, choosing two questions from
    SECTION - A
    Answer any two questions.    1 mark

Section A

  1. 3((i))A shopping mall announces a special discount on all its products as a festival offer
    only to those who satisfy any one of the following conditions.
    • If he/she is an employee of the mall and has a service of more than 10 years.
    OR
    • A regular customer of the mall whose age is less than 65 years and should
    not be an employee of the mall.
    OR
    • If he/she is a senior citizen but not a regular customer of the mall.
    The inputs are :
    INPUTS
    E Employee of the mall
    R Regular customer of the mall
    S Service of the employee is more than 10 years
    C Senior citizen of 65 years or above
    (In all the above cases, 1 indicates yes and 0 indicates no.)
    Output: X - Denotes eligible for discount [1 indicates YES and 0 indicates NO in
    all cases]
    Draw the truth table for the inputs and outputs given above and write the
    SOP expression for X ( E, R, S, C ).    5 marks
  2. 3((ii))Reduce the above expression X ( E, R, S, C ) by using 4-variable Karnaugh map,
    showing the various groups (i.e. octal, quads and pairs).
    Draw the logic gate diagram for the reduced expression. Assume that the variables
    and their complements are available as inputs.    5 marks
  3. 4((i))(a) Reduce the Boolean function F(P,Q,R,S) = (P+Q+R+S) •(P+Q+R+Sꞌ) •
    (P+Q+Rꞌ+S)•(P+Qꞌ+R+S) • (P+Qꞌ+R+Sꞌ) • (P+Qꞌ+Rꞌ+S) • (P+Qꞌ+Rꞌ+Sꞌ)
    •(Pꞌ+Q+R+S)• (Pꞌ+Q+R+Sꞌ) by using 4-variable Karnaugh map, showing the
    various groups (i.e. octal, quads and pairs).
    (b) Draw the logic gate diagram for the reduced expression. Assume that the
    variables and their complements are available as inputs.
    --------------------------------------------------------------------------------------------------------------------------------    4 marks
  4. 4((ii))From the given logic diagram :
    (a) Derive Boolean expression and draw the truth table for the derived
    expression.
    (b) If A=1, B=0 and C=1 then find the value of X.    4 marks
  5. 5((i))Draw the logic circuit to decode the following binary number (0001, 0101, 0111,
    1000, 1010, 1100, 1110,1111) to its hexadecimal equivalents. Also state the
    Hexadecimal equivalents of the given binary numbers.    5 marks
  6. 5((ii))Verify if the following proposition is valid using the truth table:
    (X ∧Y) =>Z = (Y =>Z) ∧ (X =>Y)    3 marks
  7. 5((iii))Answer the following questions related to the below image:
    (a) What is the output of the above gate if input A=0, B=1?
    (b) What are the values of the inputs if output =1?
    ----------------------------------------------------------------------------------------------------------------------------------
    SECTION – B
    Answer any two questions.
    Each program should be written in such a way that it clearly depicts the logic of the problem.
    This can be achieved by using mnemonic names and comments in the program.
    (Flowcharts and Algorithms are not required.)
    The programs must be written in Java.    1 mark
  8. 9((i))Specify the class ReCycle giving details of the functions void pushfront(int) and
    int poprear( ). Assume that the other functions have been defined.
    The main( ) function and algorithm need NOT be written.    4 marks
  9. 9((ii))Name the entity described above and state its principle.
    ----------------------------------------------------------------------------------------------------------------------------------    1 mark
  10. 11((i))A linked list is formed from the objects of the class Node. The class structure of the
    Node is given below:
    class Node
    {
    int n;
    Node link;
    }
    Write an Algorithm OR a Method to search for a number from an existing linked list.
    The method declaration is as follows:
    void FindNode( Node str, int b )    2 marks