2nd puc computer science previous year question papers with answers,2nd puc computer science question papers with answers,2nd puc computer science question papers with answers 2018

2nd puc computer science question papers with answers 2018

PART – A

Answer all the questions.
Each question carries 1 mark. (10 X 1 = 10)

      1) What is microprocessor?
      Ans: An integrated circuit that contains all the functions of a central processing unit of a computer.

      2) What is a logic gate?
      Ans: Logic gate is an electronic circuit which operates on one or more input signals to produces an output.

      3) Define sorting.
      Ans: the process of arrangement of data items in ascending or descending order is called sorting

      4) What is an object?
      Ans: object is an identifiable entity with some characteristics and behavior.

      5)      Name the pointer operator.
      Ans: address of (&) and indirection (*) operators.

      6) What is a record?
      Ans: A single entry in a table is called a record.

      7) Expand HTTP.
      Ans: Hyper Text Transfer Protocol.

      8) Write any one application of computer network.
      Ans: e-mail, file transfer protocol, telnet.

      9)      Mention any one web browser.
      Ans: internet explorer,  firefox Mozilla, opera mini, google chrome etc.

      10)  What is the use of HTML?
      Ans: Hypertext Markup Language (HTML) is the standard markup language for creating web pages and web applications.

PART - B

Answer any five questions.
Each carries 2 marks. (5 X 2 = 10)

      11) What is the minterm and maxterm?
      Ans: Minterms: “The sum of all the literals with or without bar in the logic system is called minterms”.
      Maxterms: “The product of all the literals with or without bar in the logic system is called maxterms”.

      12) Prove X.(X+Y)=X.
      Ans: LHS = X.(X+Y)

            = X.X+X.Y

            = X+XY

            = X(1+Y)

            = X.1

            = X

            =RHS

      13)  Mention any two applications of OOPs.
      Ans: - Computer graphic applications
      - CAD/CAM software
      - Object oriented database
      - User interface design such as windows
      - Real-time systems
      - Simulation and modeling
      - Artificial intelligence and expert systems

      14) Define:
      a) Constructors
      Ans: constructor is a special member function used to initialize the data members of the class
      b) Destructors
      Ans: Destructor is a special member function which is used to de-allocate memory location occupied by the object created by the constructor.

      15) Write the difference between text file and binary file.
      Ans: 1. Binary form: - The information stored is in the form of Bits.
      - No delimiters are used for a line.
      - No translation required.
      
      2. Text form: - The information stored is in the form of ASCII characters
      - Each line of text is terminated with a special character known as EOL (End Of Line) character.
      - Internal translation occurs

      16)  What is Database Management System? Give an example of DBMS software.
      Ans: DBMS is a software that allows creation, definition and manipulation of database.
      Example: Oracle, Sybase, DB2, Ingress, Informix, MS-SQL server

      17)  Give the syntax and example of UPDATE command in SQL.
      Ans: syntax: UPDATE table_name SET column1=value1,column2=value2…column=valueN WHERE[condition];
      Example: UPDATE exmployees SET address=’bengaluru’ WHERE empid=1;

      18)  Define:
      a)      Client
      Ans: client is a computer system that seeks data and information from the other computer.
      b)      Server.
      Ans: Server is a computer system that provides data and information to the other computer.

PART – C

Answer any five questions.
Each question carries 3 marks. (5 X 3 = 15)

      19)  What is cache memory? Explain their types.
      Ans: The cache memory is a very high speed memory placed in between RAM and CPU. Cache memory stores data that is used more often, temporarily and makes it available to CPU at a fast rate. During processing, the CPU first checks cache for the required data. If data is not found in cache, then it looks in the RAM for data.

Cache memory is very expensive, so it is smaller in size. Computers have cache memory of sizes 256 KB to 2 MB.

Cache memory is built into the processor and may also be located next to it on a separate chip between CPU and RAM. Cache built into CPU is faster than separate cache almost at the speed of the microprocessor itself. However separate cache is roughly twice as fast as RAM. The CPU has a built –in level 1(L1) cache and level2 (L2) cache high end processor nowadays comes with built-in L3 cache, processor like Intel Core i7.

      20)  Realize AND, OR and NOT gates using NOR gate.
      Ans: NOR-to-AND logic

NOR-to-OR logic

NOR-to-NOT

      21)  Write an algorithm to delete an element from one dimensional array.
      Ans: Step 1: item=A[P]

   Step 2: for I=P to N-1

               A[I]=A[I+1]

               End of for

   Step 3: N=N-1

   Step 4: exit

      22)  Give the advantages of pointer.
      Ans: - It is possible to write efficient programs.
      - Memory is utilized properly.
      - Dynamically allocate and de-allocate memory.
      - Easy to deal with hardware components.
      - Establishes communication between program and data.

      23)  Discuss the file mode parameters in C++.
      Ans:

Mode	Explanation
ios :: in	Open a file for reading
ios :: out	Open a file for writing
ios :: app	Appends data to the end of the file
ios :: ate	File pointer moves to the end of the file but allows to writes data in any location in the file

      24)  Explain the advantages (features) of DBMS.
      Ans: in the database approach, the data is stored at a central location and is shared among multiple users. Thus, the main advantage of DBMS is centralized data management. The advantages of centralized database system are as follows:

      - Controlled data redundancy: elimination of duplication of data item in different files ensures consistency and saves the storage space. The redundancy in the database cannot be eliminated completely as there could be some performance and technical reasons for having some amount of redundancy.

      - Enforcing data integrity: data integrity refers to the validity of data and it can be compromised in a number of ways.

      - Data sharing: the data stored in the database can be shared among multiple users or application programs. It is possible to satisfy the data requirements of the new applications without creating any additional data or with minimal modification

      - Ease of application development: the application programmer needs to develop the application programs according to user’s needs. The other issues like concurrent access, security, data integrity etc are handled by the RDBMS itself.

      - Data security: since the data is stored centrally data security checks can be carried out whenever access is attempted to sensitive data. To ensure security, a RDBMS provides security tools such as used codes and passwords. Different checks can be established for each type of access like addition, modification, deletion etc to each piece of information in the database

      - Multiple user interfaces: For various users having different technical knowledge DBMS provides different types of interfaces such as query languages, application program interfaces, and graphical user interfaces (GUI)

      - Backup and recovery: RDBMS provides backup and recovery subsystem that is responsible for recovery from hardware and software failures. For example, if the failure occurs in between the transaction, the RDBMS recovery subsystem either reverts back the database to the state to the previous state of the transaction or resumes the transaction from the point it was interrupted so that its complete effect can be recorded in the database

      25)  Write the advantages of e-commerce
      Ans: Easier entry to new markets.
      - Global participation.
      - Optimization of resources.
      - Reduces time for business transactions.
      - Improved strategic planning.

      26)  Discuss any three text formatting tags in HTML.
      Ans: <B> is used to make text Bold.
      <U> is used to draw underline.
      <I> is used to make text italics.

PART – D

Answer any seven questions.
Each question carries 5 marks. (7 X 5 = 35)

      27)  Simplify the following Boolean function using K-map.

F(A,B,C,D)=∑(1,2,3,5,7,8,9,11,13,15).

Ans:

      28) Write an algorithm to search an element using Binary search technique.
      Ans: Step 1: set B=LB, E=UB LOC=-1

   Step 2: while(B<=E)

                      M=(B+E)/2

                      If(ELE=A[M])

                      LOC=M

                  goto step 4

                      else

                              if(ELE<A[M])

                              E=M-1

                              else

                              B=M+1

                      end of while

  Step 3: if(LOC>=0)

                  PRINT LOC

            else

                  PRINT “Search is unsuccessful”

  Step 4: exit.

      29)  Give the applications of queues.
      Ans: - Simulation.
\     - Multi-programming platform systems.
      - Various features of operating system.
      - Different types of scheduling algorithm.
      - Printer server routines

      30)  Explain the characteristics of OOPs.

   Ans: Objects: An object may be a person, place or a table of data. An object is a collection of  

      data members and function members.
      Ex: Apple, Orange, Mango etc are the objects of the class fruit

Objects take memory and have addresses

Object-1(student)

  Ø  Classes: A class is a group of objects having similar characteristics. Once a class is defined, any number of objects of that class are created.
      Ex 1: man and woman belongs to the same class called Human Being
      Ex 2: planets, sun, moon are members of class solar system

 

  Ø  Data abstraction: Abstraction is a process of representing essential features without including
          background details or explanations.

  Ø  Data encapsulation: data encapsulation combines both data and functions in a single unit called class. Data encapsulation prevents data from direct access. The data can be accesses only through functions present inside the class definition. Data encapsulation enables data hiding or information hiding.

            

  Ø  Inheritance: The concept of inheritance provides the use of reusability. This means that we can 

         add additional features to the existing class without modifying it. Thus the process of acquiring 

         properties of one class to another is called inheritance. The existing class is known as base class 

         and the new class obtained is called derived class.
         The derived class shares some of the properties of the base class. Therefore a code from a base 
         class can be reused by a derived class.

  Ø  Overloading: There are two types of overloading:
      a)      Operator overloading: when existing operator operates on new data type is called operator overloading.
      b)     Function overloading: Two or more functions have same name but different number of arguments or data type of arguments. Function overloading is a process of defining same function name to carry similar types of activities with various data items.

  Ø  Polymorphism: it is a process where a function can take multiple forms based on the type of 

         arguments, number of arguments and data type of return value.
         The ability of an operator and function to take multiple forms is known as polymorphism

   Ex: int addition(int a, int b);

          int addition( float a, float b);

Consider the addition operation. In addition of two numbers the result is the sum of two numbers.

In addition of two strings the operation is string concatenation. When an operator behaves 

differently based on operands, then it is said that operator is overloaded. Similarly when same 

function is used for multiple tasks in the same program by changing argument type and number, 

it is known as function overloading.

  Ø  Dynamic binding: binding is a process of connecting one program to another. Dynamic              binding is a process of connecting one program to another during execution (when function is             called).

  Ø  Message passing: a message for an object is request for execution of procedure. Message               passing involves specifying the name of object, the name of the function and the information to           be sent.

      31)  What is the significance of using access specifiers? Explain any two access specifiers               with example.
      Ans: access specifiers are the keywords in C++ that allows access permission of the members of the class.
      There are three types of access specifiers
       - private   -protected   -public
       - private: private access means a member data can only be accessed by the member function. Members are declared under private area accessible only within the class. If no access specifier is mentioned, then by default, members are private.
      Ex: private: int x;
                       float y;
      - public: public access means that members can be accessed by any function outside the class also.
      Ex: class box
      {
      int length;
      public: int width;
      private: int height;
      void set_height(int i)
      {
      height=i;

            }

      int get_height()
      {
      return height;
      }
      };
      void main()
      { 
      box object;
      object.length=10;
      object.width=20;
      object.set_height(30);
      }

      32) Explain friend functions with syntax and programming example.
      Ans: A friend function is a non member function that is a friend of a class. The friend function is declared within a class with the prefix friend. But it should be defined outside the class like a normal function without the prefix friend.
      Syntax:
      class class_name
      {
      public: friend void function(void);
      };

      Ex: class base

            {

            int val1,val2;

            public: void getdata()

            {

            cout<<”Enter two values”;

            }

            };

           friend float mean(base ob);

           float mean(base ob)

           {

           return float(ob.val1+ob.val2)/2;

           }

      33) What is copy constructor? Explain with syntax and programming example.
      Ans: The copy constructor is a constructor which creates an object by initializing it with an object of the same class.

The copy constructor is used to −

• Initialize one object from another of the same type.
• Copy an object to pass it as an argument to a function.
• Copy an object to return it from a function.

Syntax: x a1;       //x is a class and a1 and a2 are objects of the same class

 x a2=a1;

#include<iostream.h>

#include<conio.h>

class copy

{

int var;

public:       copy(int temp)

                  {

                  var=temp;

}

int calculate()

{

int fact,i;

fact=1;

for(i=1;i<=var;i++)

fact=fact*i;

retrun fact;

}

};

void main()

{

int n;

cout<<”Enter the number: ”;

cin>>n;

copy obj(n);

copy cpy=obj;

cout<<”Before copying : ”<<n<<”!=”<<obj.calculate()<<endl;

cout<<”After copying : ”<<n<<”!=”<<cpy.calculate()<<endl;

}

      34) What are the advantages of inheritance?

Ans: Reusing existing code

- Faster development time

- Easy to maintain

- Easy to extend

- Memory utilization

      35)  Explain the differences between manual data processing and computerized (electronic) 

      data processing.
      Ans:

Manual data processing	Computerized electronic data processing
The volume of data, which can be processed, is limited.	The volume of data which can be processed can be very large.
It requires large quantities of paper.	Reasonable, less amount of paper is used.
The speed and accuracy is limited.	The job executed is faster and accurate.
Labor cost is high.	Labor cost is economical.
Storage medium is paper.	Storage medium is secondary storage medium.

      36)  What is Data Definition Language? Give the functions of Data Definition Language.
      Ans: DDL defines the conceptual schema providing link between the logical and the physical structure of the database.
      Functions of DDL:
      - It defines the physical characteristics of each record.
      - Describes the schema and subschema.
      - It indicates the keys of the records.
      - Provides data security measures.
      - It provides logical and physical data independence.

      37)  What is computer virus? Write the symptoms (characteristics) of computer virus.
      Ans: “computer virus is a malicious program that disrupts the normal functioning of the computer.”
      Symptoms or characteristics of computer virus,
      1. Unexpected pop-up windows

      2. Slow start up and slow performance

      3. Suspicious hard drive activity

      4. Lack of storage space

      5. Missing files

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