Kerala Board  Plus Two (12th) Computer Science 2023 : 3 Marks Important Question with Solution

Kerala Board  Plus Two (12th) Computer Science 2023 : 3 Marks Important Question with Solution

This Post contains Plus Two ( 12th ) Computer Science Focus Area Notes PDF and Key Points for Class 12th Computer Science Notes are designed by expert teachers from the latest edition to get good marks in board exams. Students can Read the Plus Two Computer Science Focus Area Notes from our website for free.

3 Marks Important Question

1. Distinguish between array and structure.

Ans.

2. Explain about operations performed on stack data structure.

Ans. The operations on stack are:
1. Push – An operation of insertion into a stack.
2. Pop - A process of deletion from a stack
In stack, push and pop operations are done on one end called top

3. Write any three differences between static and dynamic web pages.

Ans .

4. What is a hyperlink ? Explain about different types of hyperlinks available in HTML.

Ans. A hyperlink is an element, a text, or an image in a web page that allows visitors to navigate between websites. The tag provides the facility to give hyperlinks. Different types of links are: Internal linking (link to same document), external linking(Link to another document), Email linking (link to a mail).

5. Explain about any two control structures used in JavaScript with example.

Ans. 1. if – if is used to execute a statement or a group of statements based on some conditions. Its syntax is: if (condition ) { statements }
2. For loop – for loop is used to execute a group of instructions repeatedly. Syntax : for ( initialisation ; test expression ; update expression ) { body of loop }

6. Write a note about different types of web hosting.

Ans. 1. Shared hosting – common type, share resources like RAM and CPU, suitable for small websites, cheaper and easy to use
2. Dedicated hosting - the client leases the entire web server and all its resources, suitable for large organisations, guaranteed performance and expensive
3. Virtual Private Server – Each VPS works similar to a dedicated server, Each of these VPS works as a fully independent web server, as if each were running on a separate physical server.

7. Explain about union, intersection and set difference operations in relational algebra.

Ans. Union – returns a relation containing all tuples appearing in either or both of the two relations. It is denoted by U.
Intersection – returns a relation containing the tuples appearing in both of the two specified relations. It is denoted by ∩.
Set difference – this returns a relation containing the tuples in the first relation but not in the second. Its symbol is –

8. Explain about different components of SQL.

Ans. DDL (Data Definition Language) – create table , alter table , drop table
DML (Data Manipulation Language) – insert into, delete, update, select
DCL (Data Control Language) – grant, revoke

9. Prepare a short note about different data types used in PHP.

Ans. Data types in PHP can be divided into two :

1. Core data types - (integer, float, string, boolean). These are similar to the data types in C++

2. Special data types - (null, array, object, resources).

10. Explain the advantages and disadvantages of cloud computing.

Ans. Advantages – reduced cost, scalability/flexibility, reliability, maintenance, mobile accessible
Disadvantages – security and privacy issues, lack of standards

11. What is e – governance ? List the different types of interactions in e-governance.

Ans. Delivering government services to public in a convenient, efficient and transparent
manner is called as e - Governance. Different types of interactions in e-Governance are:
G2G(Government to Government), G2C(Government to Citizens), G2B(Government to
Business) and G2E (government to Employees)

12. What are the different memory allocations in C++? Explain

Ans.

13. What is Polymorphism. Give an example.

Ans. Polymorphism is the ability of a programming language to process objects differently
depending on their data types or class.
Eg: Area of different shapes

14. Write an algorithm to insert new item into a queue.

Ans.
step 1: if (rear= =Max-1)
step 2: Print “Overflow”
step 3: Else
step 4: Rear++;
step 5: Queue [Rear] = item

15. Differentiate between Static webpage and dynamic webpage
Ans.

16. Briefly explain the different ways in which a JavaScript can be inserted in a webpage

Ans. There are three ways to insert JavaScript in a web page.
1) Inside <head> - As the body section of the HTML page contains large volume of text, this is said to be the best practice. This avoids the confusion of web designer.
2 ) Inside <body> - Here, the script will be executed while the contents of the web page is being loaded.
3) As an external JavaScript file with explanations – Here, the .js file is linked to the HTML file as an external file.

17. Distinguish between shared hosting and dedicated hosting.

Ans.

18. Explain different level of data abstraction in DBMS.

Ans. There are three abstraction Levels in DBMS. They are:
1) Physical Level : This is the lowest level of abstraction. Here, how data is actually stored is described.
2) Logical Level : Here, what data are stored in the data base is described. What are the relationships existing among the data are also specified.
3) View Level : This is the highest level of data base abstraction. It is concerned with the  view in which individual users view the data.

19. Describe Union and intersection operation in relational algebra with suitable examples.

Ans. Union: The resultant relation contains all tuples in either or both relations. The union of two relations A and B is written as AUB.

Intersection: The resultant relation contains all tuples common in both relations. The intersection of two relations A and B is written as A∩B

20. Write PHP code to display even numbers below 100 

Ans. <?php
$i = 2 ;
do {
echo ” $i ” ;
$i=$i+2;
} while ($i< = 100 ) ;

21. Explain cloud service models.

Ans. There are three cloud service Models

1. Software as a Service ( SaaS) : - A SaaS provider gives users to access both resources and applications.
2. Platform as a Service ( Paas ) : - A PaaS provider gives users to access the components that they require to develop and operate applications.
3. Infrastructure as a Service ( Iaas) : - IaaS provides basic storage and computing capabilities as standardized services.

22. List and explain any three e-learning tools.

Ans. The three e -Learning tools are:
1. e - Text – Textual information available in electronic format.
2. e – Books – books stored in digital format
3. Online chats – real time exchange of text messages between two or more persons over
internet

23. What is a pointer in C++ ? Declare a pointer and initialize with the name of your country.

Ans. Pointer is a variable that can hold the address of a memory location. It is a primitive since it contains memory address which is atomic in nature. char *name_of_nation = “ India “ ;

24. What is Object Oriented Programming ? What are disadvantages of Procedural oriented Programming ?

Ans. Object Oriented Programming is a programming methodology in which the main importance is given to objects. Procedures have only secondary status. Disadvantages of Procedural Oriented Programming are: 1. Data is undervalued, 2. Adding new data requires modification of many functions, 3. Creating new data type is difficult, 4. Poor real world modelling etc :-

25. Write an algorithm to add a new item into a Queue.

Ans. Step 1: if ( Rear < N -1 ) Then
Step 2: Rear = Rear + 1
Step 3: Q [ Rear ] = Val
Step 4: else
Step 5: Print “ Queue Overflow “

26. List and explain any three attributes of INPUT tag in HTML
Ans. Attributes of INPUT tag are:

1. Type :- This attribute determines the control type created by the INPUT tag.
2. Value :- This is used t provide an initial value inside the control.
3. Name :- This is used to give a name to the input control.

27. Consider a string “ Gandhiji “. Write JavaScript code fragment to do the following tasks.
( a ) Convert the string to upper case
( b ) Find the length of the string
( c ) Display the 3rd letter in the string

Ans. ( a) toUpperCase ( “ Gandhiji ”) ;
( b ) var a = “ Gandhiji “ ;
var n = a.length ;
( c ) var a = “ Gandhiji “ ;
var x = a. charAt ( 2 ) ;

28. What is FTP client software? Differentiate FTP and SFTP.

Ans. FTP is used to transfer files from one computer to another on the internet. Full form of FTP is File Transfer Protocol. SFTP means Secured File Transfer Protocol. It is actually SSH FTP which encrypts and sends user names, passwords and data to the web server. SFTP uses Secure Shell Protocol which provides facilities for secure file transfer

29. List and explain different database users in DBMS

Ans.: 1. DBA: - Data Base Administrator ( DBA ) is responsible for all the critical activities in DBMS. He has the overall control over data base.
2. Application programmers: - These are computer professionals who interact with the DBMS through application programs.
3. Naïve users: - Naïve users interact with the system by one of the application programs written previously. They are common users who have no knowledge about DBMS.

30. Differentiate DELETE and DROP in SQL. Write the syntax of DELETE and DROP.

Ans. DELETE command is used to remove individual or set of rows from a table. Syntax : DELETE FROM < table name > [ WHERE < condition > ] ; DROP command is used to remove a table from the database. Syntax: DROP TABLE < table name > ;

31. Name the different types of arrays in PHP. Explain with an example.

Ans. In PHP, there are three types of arrays.
1) Indexed arrays.
2) Associative arrays
3) Multi-Dimensional arrays Indexed array: Arrays with numeric index are called Indexed arrays. They are almost similar to arrays in C++. eg:- $array_name = array (value1,value2,….) ; Associative array: Arrays with named keys are called as associative arrays. Eg:- $array_name = array ( key=>value1, key=>value2,….) ;

32. Discuss any three information security laws for protecting information shred over cyber space.

Ans. 1. Patents: A patent is the exclusive rights granted for an invention. It is the legal right obtained by the inventor for exclusive control over the production.
2. Trademark: A trademark is distinctive sign that identifies certain goods or services produced by an individual or a company. A trademark can be a name, a symbol, a logo etc.
3. Copyright: A copyright is a legal right given to the creators for an original work, usually for a limited period of time.

33. Briefly explain any three application of computational intelligence.

Ans. 1. Biometrics : It refers to the measurements related to human characteristics and traits. Biometric authentication is used in identification of individual.
2. Robotics : Robotics can be defined as the scientific study associated with the design, fabrication and application of robots.

3. Computer Vision: Computer vision is the construction of explicit and meaningful description of structure and properties of 3-D world from 2-D images. It is also called as image understanding

34. Read the following code Fragment:
Int a[ ]= {5,10,15,25};
Int *p=a;
Predict the output of the following statements:
(a) cout<<*p;
(b) cout<<*p+1;
(c) cout<<*(p+1);

Ans.
(a)5
(b)6
(c)10

35. What is object-oriented paradigm? Give any two advantages.

Ans. In object oriented paradigm data and functions that operate on that data is tied together as a single unit called an object.
Advantages of OOP:
1.It can be used to implement real life scenarios
2.It is good for defining abstract datatypes

36. What is data structures? How are they classified?

Ans. Data types is the way of organizing same or different logically related data items which can be processed as a single unit. Data structures are mainly divided into:
1.Simple data structures
2.Compound data structures Simple data structure consists of array and structures. Compound data structure is again divided into linear and nonlinear data structure. Linear data structure consists of stack, queue and linked list. Compound data structure is divided into trees and graphs

37. List and explain any three attributes of body tag in HTML.

Ans. Three attributes of BODY tag are:
1) Background – To set an image as background
2) Bgcolor – To specify a colour of a background of the document body
3) Text – to specify the colour of the text content in the page.

38. Identify the suitable JavaScript datatypes for the following:
(a) “Supercomputer”
(b) “true”
(c ) 67.5

Ans.
(a) String
(b)String
(c) number

39. What is Responsive web design ? What is its significance in modern computing devices?

Ans. Responsive web design is the custom of building a website suitable to work on every device and every screen size, no matter how large or small, mobile phone or desktop or television.

40.Define the following terms:
(a) Relation
(b) Candidate Key
(c) Tuples and attributes

Ans.
(a) Relation Collection of data organized in rows and column format. Relation is also called as table.
(b)Candidate Key Candidate Key is the minimal set of keys that uniquely identifies a row in a relation
(c) Tuples and attributes. Row in a relation is called Tuple. Column in a relation is called Attribute

41.Write short notes on any three data types in SQL

Ans. 1.Numeric Datatype int or integer: Represent integer numbers Dec or Decimal: Represent fractional numbers
2. String Char: Represent fixed length character data type Varchar: Represent variable length strings
3,Date and Time datatype Date: used to store date . Format is yymmdd Time: used to store time. Format is hh:mm:ss

42. What is the difference between echo and print in PHP?

Ans. In PHP echo and print are used to display output on webpage

43. Define the following cyber crimes
( a) Identity Theft
(b ) Harrassment
(c ) Impersonation and cheating

Ans. (a)Identity theft occurs when someone uses another person’s identifying information Such as name, credit card numbers etc, without their permission to commit crimes
(b)Harassment: Posting humiliating comments focusing on gender, religion, nationality at specific individuals in chat rooms, social media, email etc is called harassment
(c) Impersonation and cheating: Impersonation is an act of pretending to be another person for the purpose of harming the victim

44. Briefly explain different type of cloud service.

Ans. There are three cloud service Models
1. Software as a Service ( SaaS) : - A SaaS provider gives users to access both resources and applications.
2. Platform as a Service ( Paas ) : - A PaaS provider gives users to access the components athat they require to develop and operate applications.
3. Infrastructure as a Service ( Iaas) : - IaaS provides basic storage and computing computing capabilities as standardized services.

45. Differentiate between CHAR and VARCHAR data types in SQL

Ans. CHAR is fixed length character data type. Its syntax is CHAR ( x ).
VARCHAR represents variable length strings. VARCHAR type saves memory.

46. Name the appropriate SQL datatypes required to store the following data 
a) Name of a student (Maximum 70 characters)
b) Date of birth of a student
c) Percentage of marks obtained (correct to two decimal places)

Ans. a) varchar(70)
b) date
c) decimal(8,2)

Kerala Board Class 12 Study Materials