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ISC Class XII Exam 2020 : Computer Science Paper 1 (Theory)

9 pages, 18 questions, 1 questions with responses, 1 total responses,

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COMPUTER SCIENCE PAPER 1 (THEORY) (Maximum Marks: 70) (Time allowed: Three hours) (Candidates are allowed additional 15 minutes for only reading the paper. They must NOT start writing during this time.) ------------------------------------------------------------------------------------------------------------------------------- Answer all questions in Part I (compulsory) and six questions from Part-II, choosing two questions from Section -A, two from Section-B and two from Section-C. All working, including rough work, should be done on the same sheet as the rest of the answer. The intended marks for questions or parts of questions are given in brackets [ ]. --------------------------------------------------------------------------------------------------------------------PART I (20 Marks) Answer all questions. While answering questions in this Part, indicate briefly your working and reasoning, wherever required. Question 1 (a) State Associative law and prove it with the help of a truth table. [1] (b) Draw the truth table to prove the proportional logic expression. [1] (X => Y) (Y => X) = X <=> Y (c) Find the dual for the Boolean equation: AB + BC + 1 = 1. [1] (d) Convert the Boolean expression F(X,Y,Z) = X Y Z + X YZ + XYZ into its cardinal form. [1] (e) Minimize: F = XY + (XZ) +XY Z using Boolean laws. [1] Question 2 (a) Differentiate between Stack data structure and Queue data structure. [2] (b) Convert the following infix notation to postfix notation [2] A*(B/C)/E+F (c) Define Interface. How is it different from a Class? [2] ----------------------------------------------------------------------------------------------------------------------------------- 1 ISC SPECIMEN QUESTION PAPER 2020 (d) Each element of an array arr[15][20] requires W bytes of storage. If the address of arr[6][8] is 4440 and the Base Address at arr[1][1] is 4000 , find the width W of each cell in the array arr[ ][ ] when the array is stored as Column Major Wise. [2] (e) Define Big O notation. State the two factors which determine the complexity of an algorithm. [2] Question 3 The following is a function of some class. What will be the output of the function test ( ) when the value of count is equal to 4 ? Show the dry run / working. [5] void test (int count) { if (count = = 0) System.out.println( ); else { System.out.println( Bye + count); test( --count ); System.out.println( + count); } } ----------------------------------------------------------------------------------------------------------------------------------- 2 ISC SPECIMEN QUESTION PAPER 2020 PART II (50 Marks) Answer six questions in this part, choosing two questions from Section A, two from Section B and two from Section C. SECTION - A Answer any two questions. Question 4 (a) Given the Boolean function F(A, B, C, D) = ( 0, 2, 3, 6, 8, 10, 11, 14, 15 ) (i) (ii) (b) Reduce the above expression 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. [4] [1] Given the Boolean function F(P,Q,R,S) = ( 5, 7, 8, 10, 12, 14, 15 ) (i) Reduce the above expression by using 4-variable Karnaugh map, showing the various groups (i.e. octal, quads and pairs). [4] (ii) Draw the logic gate diagram for the reduced expression. Assume that the variables and their complements are available as inputs. [1] (a) Draw the logic diagram and truth table to encode the decimal numbers ( 2, 3, 5, 7, 8 ) and briefly explain its working [5] (b) Simplify the following Boolean expression and draw the gate for the reduced expression: [3] Question 5 F= A B + AB C + A (c) Define Universal gates. Give one example and show how it works as an OR gate. [2] Question 6 (a) Draw a truth table with a 3 input combination which outputs 1 if there are odd number of 0 s. Also derive an SOP expression for the output. Reduce the expression using Karnaugh Map. [5] (b) Define Proposition. How does tautology differ from contradiction? [3] (c) Draw the logic diagram of 4:1 Multiplexer. [2] ----------------------------------------------------------------------------------------------------------------------------------- 3 ISC SPECIMEN QUESTION PAPER 2020 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. Question 7 A class Composite contains a two dimensional array of order [m x n]. The maximum value possible for both m and n is 20. Design a class Composite to fill the array with the first (m x n) composite numbers in column wise. The details of the members of the class are given below: : Composite arr[ ] [ ] : stores the composite numbers column wise m : integer to store the number of rows n : integer to store the number of columns Composite(int mm, int nn ) : to initialize the size of the matrix m=mm and n=nn int isComposite( int p ) : returns 1 if number is composite otherwise returns 0 void fill ( ) : to fill the elements of the array with the first (m n) composite numbers in column wise void display( ) : displays the array in a matrix form Class name Data members/instance variables: Member functions/methods: Specify the class Composite giving details of the constructor(int,int), int isComposite(int), void fill( ) and void display( ). Define a main( ) function to create an object and call the functions accordingly to enable the task. ----------------------------------------------------------------------------------------------------------------------------------- 4 ISC SPECIMEN QUESTION PAPER 2020 [10] Question 8 Design a class Sort which enables a word to be arranged in alphabetical order. The details of the members of the class are given below : Class name [10] : Sort Data members/instance variables: str : stores a word len : to store the length of the word Methods/Member functions: Sort( ) : default constructor void readword( ) : to accept the word void arrange ( ) : to arrange the word in alphabetical order using any standard sorting technique. void display( ) : displays the original word along with the sorted word Specify the class Sort giving details of the constructor, void readword( ), void arrange( ) and void display( ). Define the main( ) function to create an object and call the functions accordingly to enable the task ----------------------------------------------------------------------------------------------------------------------------------- 5 ISC SPECIMEN QUESTION PAPER 2020 Question 9 A Special number is a number in which the sum of the factorial of its digits is equal to the number. [10] Example: 145 ( 1! + 4! + 5! = 145 ). Thus, 145 is a Special number. Design a class Special to check if the given number is a Special number or not. Some of the members of the class are given below: Class name : Special : integer to store number Special( ) : default constructor void read( ) : to accept the number int factorial(int x) : return the factorial of a number using recursive technique boolean isSpecial( ) : checks for the special number by invoking the function factorial( ) and returns true if Special, otherwise returns false void display( ) : displays the result with an appropriate message Data member/instance variable: n Member functions/methods: Specify the class Special, giving details of the Constructor, void read( ), int factorial(int), boolean isSpecial( ) and void display( ). Define the main() function to create an object and call the member function according to enable the task. ----------------------------------------------------------------------------------------------------------------------------------- 6 ISC SPECIMEN QUESTION PAPER 2020 SECTION C Answer any two questions. Each Program should be written in such a way that it clearly depicts the logic of the problem step wise. This can also be achieved by using comments in the program and mnemonic names or pseudo codes for algorithms. The program must be written in Java and the algorithms must be written in general / standard form, wherever required / specified. (Flowcharts are not required.) Question 10 An interface Shape is defined with a method area() which returns the area of the implementing shape. [5] Create the classes Circle and Rectangle which implement the interface Shape. These classes have attributes which reflect their dimensions (radius for a circle, height and width for a rectangle) which are set by their constructors. The details of the members of the interface and both the classes are given below: Interface name Member functions/methods: double area() : Shape : returns the area of the implementing shape Class name : Circle Data members/instance variables: radius : to store radius of the circle in decimal Member functions/methods: Circle(int r) double area() : parameterized constructor to initiallize radius=r : to calculate area of the circle [ area of a circle is 3.14*radius*radius] Class name : Rectangle Data members/instance variables: length breadth Member functions / methods Rectangle(int l, int b) double area() : to store length of the rectangle in decimal : to store breadth of the rectangle in decimal : parameterized constructor to initialize length=l, breadth=b : to calculate area of the rectangle [ area of a rectangle is length*breadth] Assume that the Interface Shape has been defined. Using the concept of inheritance, specify the classes Circle and Rectangle giving details of their constructors and double area( ) respectively. The interface, main function and algorithm need NOT be written. ----------------------------------------------------------------------------------------------------------------------------------- 7 ISC SPECIMEN QUESTION PAPER 2020 Question 11 Circular Queue is a linear data structure in which the operations are performed based on [5] FIFO (First In First Out) principle and the last position is connected back to the first position to make a circle. Define a class Cqueue with the following details: Class name Data member/instance variable: ele[ ] cap front rear Member functions/methods: Cqueue(int max) : Cqueue : : : : array to hold the integer elements stores the maximum capacity of the array to point the index of the front to point the index of the rear. : constructor to initialize the data member cap = max, front = rear = 0 and create the integer array void insert(int v) : to add integers from the front index if possible else display the message( full from rear ) int delete( ) : to remove and return elements from rear, if any, else returns -999 void display() : to display elements of circular queue Specify the class Cqueue giving the details of void insert(int) and int delete( ). Assume that the other functions have been defined. The main( ) function and algorithm need NOT be written. ----------------------------------------------------------------------------------------------------------------------------------- 8 ISC SPECIMEN QUESTION PAPER 2020 Question 12 (a) A linked list is formed from the objects of the class Node. The class structure of the Node is given below: [2] Class Node { int num; Node next; } Write an Algorithm OR a Method to insert a node at the beginning of an existing linked list. The method declaration is as follows: void InsertNode( Node starPtr, int n ) (b) Answer the following questions from the diagram of a Binary Tree given below: (i) Name the Root and the leaves of the tree. [1] (ii) Write the post order traversal of the tree. [1] (iii) Separate the Internal nodes and the External nodes of the tree. [1] (NOTE: The total weightage of questions in the Question Paper will be as indicated in the Specimen Paper. However, breakup of subparts in questions may vary from year to year.) ----------------------------------------------------------------------------------------------------------------------------------- 9 ISC SPECIMEN QUESTION PAPER 2020

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