2nd puc computer science question papers with answers 2016

  

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2nd puc computer science question papers with answers 2016

PART – A

Note:
i) Answer all questions.
ii) Each question carries one mark. 10 X 1 = 10

      1. What is DHTML?
      Ans: : Dynamic HyperText Markup Language refers to web content that changes each time it is viewed.

      2. Define e-commerce.
      Ans: e-commerce is the trade of goods and services with the help of telecommunications and computers.

      3. Define Local Area Networking.
      Ans: A local area network (LAN) is a computer network that interconnects computers within a limited area such as a residence, school, laboratory, university campus or office building.

      4. Define the term ‘topology’ of computer networks.
      Ans: the actual appearance or layout of networking.

      5. Define data mining.
      Ans: data mining is concerned with the analysis and picking out relevant information.

      6. How do you initialize a pointer variable?
      Ans: Pointer_variable=Address_operator common_ variable_name;
      Ex: int *ptr,a;

      ptr=&a;

      7. What is the significance of scope resolution operation in C++?
      Ans: scope resolution (::) operator is used to define the member function outside the class definition.

      8. Name any one non-linear data structure.
      Ans: trees and graphs.

      9. Write the standard symbol of XOR gate.
      Ans: 

      10. Expand ISA.
      Ans: Industry Standard Architecture. 

PART – B

Note:
i) Answer any five questions.
ii) Each question carries two marks. 5 X 2 = 10

       11. Prove (X+Y)(X+Z)=X+YZ using algebraic method.
       Ans: XX+XZ+YX+YZ     | distributive law

  =X+XZ+XY+YZ     | indempotence law

  =X(1+Z+Y)+YZ     | properties of 0 and 1

  =X.1+YZ

  =X+YZ

  =RHS

       12. Give the general syntax for defining classes and objects.
       Ans:  General Syntax for defining class:
       class class_name
       {
        private: data member;
        function member;
        protected: data member;
        function member;
        public: data member;
        function member;
       };
       General syntax for defining an object:
       class_name object_name;

       13. What are minterms and maxterms?

       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”.

       14. Mention any two antivirus softwares.
       Ans: PANDA, McAfee, Avast, Quickheal, Kaspersky etc.

       15. Write the syntax for delete and insert commands in SQL.
       Ans: delete from table_name where [column_name=value];
       insert into table_name values(value1,value2,…valueN);

       16. Write any two rules for constructors.

 Ans:  

- A constructor name is always same as that of the class name.

- There is no return type for the constructors not even void.

       17. Write any two member functions belonging to ofstream class.
       Ans: put(), write().

       18. What are the advantages and disadvantages of ISAM?
       Ans:
       Advantages:
        - Permits efficient and economical use of sequential processing techniques when the activity ratio is high.
      - Permits direct access processing of records in a relatively efficient way when the activity ratio is low.

Disadvantages:

- Files must be stored in a direct access storage device.

- Hardware and software is expensive.

- Access to records may be slower than direct file.

PART – C

Note:
i) Answer any five questions.
ii) Each question carries three marks. 5 X 3 = 15

      19. What is web hosting? Mention various web hosting services.
      Ans: web hosting is a business of providing storage space and access for websites.
      Various web hosting services are,

      1. Free hosting.

      2. Virtual or Shared hosting.

      3. Dedicated hosting.

      4. Collocation hosting.

       20. What is meant by shareware? Write its limitations.

       Ans: software made available with the right to redistribute copies, but it is stipulated that if one intends to use the software, often after a certain period of time, then a license fee should be paid.

      Limitations of shareware:

       i) In shareware the source code is not available.

       ii) Modifications to the software are not allowed.

       21. Explain relational data model with an example.

 Ans: Relational model: the relational model was developed by E.F.Codd in 1970. In relational 

 model there are no physical links. All data is maintained in the form of tables (generally 

 known as relations) consisting of rows and columns. Each row or record represents an  

 entity and a column or field represents an attribute of the entity. Oracle, Sybase, DB2, 

 Ingress, Informix, MS-SQL server are the examples of DBMSs

In this model, data is organised in two-dimensional tables called relations. The tables or relations are related to each other.

Relational model of database

       22. Give the functions of the following:

       a) get()

       ans: the get() function belongs to the class ifstream and the function get() reads a single character.

       b) getline()
       ans: it is used to read a whole line of text. It belongs to the class ifstream.
       c) read()
       ans: the read() member function belongs to the class ifstream and which is used to read binary data 
       from a file.

       23. Explain the use of new and delete operators in pointers.
       Ans: These operators allocate memory for objects from a pool called the free store. The new operator calls the special function operator new and the delete operator calls the special function operator delete

Example, to allocate memory of type integer, int *iptr=new int;

                  To allocate memory of type float, float *fptr=new float;

                  To allocate memory of type double, double *dptr=new double;

Releasing dynamic memory using delete as: delete iptr;

      24. What is stack? Write an algorithm for pop operation.
      Ans: a stack is an ordered collection of items where the addition of new items and the removal of existing items always take place at the same end. This technique uses LIFO principle.

      25. Draw the logic diagram and truth table for 2 input XOR gate.
      Ans:

 

       26. Expand UPS. Explain the types of UPS.

      Ans: electronic components of a computer system require continuous supply of electric current for their operations to prevent them from the failures, break down or shutdown.

      

      There are two types of power supply connected to a computer system; they are Switched Mode Power Supply (SMPS) and Uninterruptable Power Supply (UPS).

      
      - SMPS: it converts AC power into DC power. It is a metal box in the rear of the system. It contains the power card plug and a fan for cooling, because it generates a lot of heat. SMPS with a power of 300 watts is needed. It converts 230 volts of AC to 5 to 12 DC volts and the wattage is around 180 to 300 watts, 450 watts and 500 watts
      
      - UPS: An UPS is a power supply that includes a battery to maintain power in the event of a power failure. An UPS keeps a computer running for several minutes to few hours after a power failure, enabling us to save data the is in RAM and then shut down the computer
      There are two types of UPS: Online UPS and standby UPS
      
      - Online UPS: it provides continuous power to the system from its own inverter when the power goes off. For a PC with color monitor 15”, requires an UPS of 500 VA and for a PC with color monitor 17”, requires an UPS of 600 VA

      - Standby UPS or Offline UPS: it monitors the power line and switches to battery power as soon as it detects a problem. The switch over to battery however, can require several milliseconds, during which time the computer is not receiving any power

 

PART – D

Note:
i) Answer any seven questions.
ii) Each question carries five marks. 7 X 5 = 35

      27.      Write an algorithm to insert an element into a queue.
      Ans: Step 1: if REAR=N then

                  PRINT “overflow”

                  Exit

      Step 2: if FRONT=NULL then

                  FRONT=0

                  REAR=0

Else

REAR=REAR+1

            Step 3: QUEUE[REAR]=ITEM

            Step 4: return

      28.      Write an algorithm for insertion sort method.
      Ans: Step 1: for P=1 to N-1

   Step 2: temp=A[P]

                  PTR=P-1

  Step 3: while temp<A[PTR]

                              A[PTR+1]=A[PTR]

                              PTR=PTR-1

                  End of while

 Step 4: A[PTR+1]=temp

                  End of for

 Step 5: exit

      29. Using K-map, simplify the following expression in four variables:

      F(A,B,C,D)=m₁+m₂+m₄+m₅+m₉+m₁₁+m₁₂+m₁₃.

Ans: 

       30. Write the rules for to be followed in writing constructor function in C++.

 Ans: - A constructor name is always same as that of the class name
- There is no return type for the constructors not even void
- A constructor should be declared in public section
- A constructor is invoked automatically when objects are created
- It is not possible to refer to the address of constructors
- The constructors make implicit calls to the operators new and delete when memory allocation is required.

      31.      Describe briefly the use of friend function in C++ with syntax and 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;

        }

       32. Explain defining objects of a class with syntax and a programming example.
       Ans: General Syntax for defining class:
       class class_name
       {
        private: data member;
        function member;
        protected: data member;
        function member;
        public: data member;
        function member;
        };
      General syntax for defining an object:
       class_name object_name;
      Programming example:
      #include<iostream.h>
      #include<conio.h>
      class test
     {
      int a,b;
      public: void getdata()
     {
      cout<<”Enter two numbers: ”;
      cin>>a>>b;
      }
      void display()
      {
       cout<<”Addition of two numbers: ”<<a+b;
       }

       };

       void main()

       {

       test t;

       t.getdata();

       t.display();

       getch();

       }

       
       33. Define object oriented programming. Write the limitations of object oriented programming.
      Ans: Object-oriented programming aims to implement real-world entities like inheritance, hiding, polymorphism, etc in programming.
      Limitations of OOP:
      - OOP software is not having set standards.
      - The adaptability of flow diagrams and object oriented programming using classes and objects is 
      a complex process.
      - To convert a real world problem into an object oriented model is difficult.
      - The classes are overly generalized. 

      34. Explain network securities in detail.
      Ans: Authorization: Authorization is the process of allowing an authenticated users to access the resources by checking whether the user has access rights to the system. Authorization helps you to control access rights by granting or denying specific permissions to an authenticated user.
      
      - Authentication: Authentication is the process of verifying the identity of a user by obtaining some sort of credentials and using those credentials to verify the user's identity. If the credentials are valid, the authorization process starts. Authentication process always proceeds to Authorization process.
     
      - Encrypted smart cards: Confidentiality is the use of encryption to protect information from unauthorized disclosure. Plain text is turned into cipher text via an algorithm, then decrypted back into plain text using the same method.
      Cryptography is the method of converting data from a human readable form to a modified form, and then back to its original readable form, to make unauthorized access difficult.
    
      - Biometric systems: it involves unique aspects of a person’s body such as finger prints, retinal patterns, etc to establish his/her identity.

      - Firewall: A firewall is a network security system designed to prevent unauthorized access to or from a private network. Firewalls can be implemented in both hardware and software, or a combination of both. Network firewalls are frequently used to prevent unauthorized Internet users from accessing private networks connected to the Internet, especially intranets. All messages entering or leaving the intranet pass through the firewall, which examines each message and blocks those that do not meet the specified security criteria.

      35. Describe any five logical operators available in SQL.
      Ans: ALL: This operator is used to compare a value to all values in another value set.
      AND: This operator allows the existence of multiple conditions in an SQL statements’ WHERE clause.
      EXISTS: This operator is used to search for the presence of a row in a specified table that meets certain criteria.
      LIKE: This operator is used to compare a value to similar values using wildcard operators
      IS NULL: This operator is used to compare a value with a NULL value.

      36. Write the differences between Manual and 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.

      37. Explain briefly the types of inheritance.
      Ans: - Single inheritance: if a class is derived from a single base class, it is called as single inheritance

- Multilevel inheritance: the classes can also be derived from the classes that are already derived.

This type of inheritance is called multilevel inheritance.

- Multiple inheritance: if a class is derived from more than one base class, it is known as 

multiple inheritance.

- Hierarchical inheritance: if a number of classes are derived from a single base class, it is called as hierarchical inheritance.

- Hybrid inheritance: it is a combination of Hierarchical and Multiple inheritance.