Category: Class 12

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NEET Biology MCQ

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Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Science Guide Pdf Chapter 11 Database Concepts Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Computer Science Solutions Chapter 11 Database Concepts

12th Computer Science Guide Database Concepts Text Book Questions and Answers

I. Choose the best answer (1 Marks)

Question 1.
What is the acronym of DBMS?
a) Data Base Management Symbol
b) Database Managing System
c) Data Base Management System
d) DataBasic Management System
Answer:
c) Data Base Management System

Question 2.
A table is known as
a) tuple
b) attribute
c) relation
d) entity
Answer:
c) relation

Question 3.
Which database model represents parent-child relationship?
a) Relational
b) Network
c) Hierarchical
d) Object
Answer:
c) Hierarchical

Question 4.
Relational database model was first proposed by
a) E F Codd
b) E E Codd
c) E F Cadd
d) E F Codder
Answer:
a) E F Codd

Question 5.
What type of relationship does hierarchical model represents?
a) one-to-one
b) one-to-many
c) many-to-one
d) many-to-many
Answer:
b) one-to-many

Question 6.
Who is called Father of Relational Database from the following?
a) Chris Date
b) Hugh Darween
c) Edgar Frank Codd
d) Edgar Frank Cadd
Answer:
c) Edgar Frank Codd

Question 7.
Which of the following is an RDBMS?
a) Dbase
b) Foxpro
c) Microsoft Access
d) SQLite
Answer:
d) SQLite

Question 8.
What symbol is used for SELECT statement?
a) o
b) n
c) X
d) Q
Answer:
a) o

Question 9.
A tuple is also known as
a) table
b) row
c) attribute
d) field
Answer:
b) row

Question 10.
Who developed ER model?
a) Chen
b) EF Codd
c) Chend
d) Chand
Answer:
a) Chen

II. Answer the following questions (2 Marks)

Question 1.
Mention few examples of a database.
Answer:
dbase-III , dbase-III Plus, Foxbase , Foxpro ,SQL Server, Oracle Database, Sybase, Informix, MySQL are some examples of Database languages which are used to design ERP applications like Payroll, Railway Reservation System, Inventory Systems.

Question 2.
List some examples of RDBMS.
Answer:
SQL Server, Oracle Database, Sybase, Informix, MySQL.

Question 3.
What is data consistency?
Answer:
Data Consistency
On live data, it is being continuously updated and added, maintaining the consistency of data can become a challenge. But DBMS handles it by itself. Data Consistency means that data values are the same at all instances of a database.

Question 4.
What is the difference between the Hierarchical and Network data model?
Answer:

Hierarchical Data Model		Network Data Model
1	A child record has only one parent node	A child may have many parent nodes
2	It represents the data in one-to-many relationships	It represents the data in many-to-many relationships
3	This model is not easier and faster to access the data than the Network data model.	This model is easier and faster to access the data.

Question 5.
What is normalization?
Answer:

• Normalization is a process of organizing the data in the database to avoid data redundancy and to improve data integrity.
• Database normalization was first proposed by Dr. Edgar F Codd as an integral part of RDBMS. These rules are known as the E F Codd Rules.

III. Answer the following questions (3 Marks)

Question 1.
What is the difference between Select and Project
Answer:

Select	Project
The SELECT operation(o) is used for selecting a subset with tuples according to a given selection condition.	The projection method(n) eliminates all attributes of the input relation but those mentioned in the projection list.
The SELECT operation (o) selects filters out all tuples that do not satisfy the condition.	The projection method defines a relation that contains a vertical subset of Relation.
Symbol: σ	Symbol: π
General Form: σ (R) c Example: σ = “Big Data” (STUDENT) course	Example: π  (STUDENT) course

Question 2.
What is the role of DBA?
Answer:

1. Database Administrator or DBA is the one who manages the complete database management system.
2. DBA takes care of the security of the DBMS, managing the license keys, managing user accounts and access etc.

Question 3.
Explain Cartesian Product with a suitable example.
Answer:

• Cross product is a way of combining two relations.
• The resulting relation contains, both relations being combined.
• A x B means A times B, where the relation A and B have different attributes.
• This type of operation is helpful to merge columns from two relations

studno	name	studno	subject
cs1	Kannan	cs28	Big Data
cs2	Gowri Shankar	cs62	R language
cs4	Padmaja	cs25	Python Programming

Cartesian product; Table A x Table B

studno	name	course	subject
cs1	Kannan	cs28	Big Data
cs1	Kannan	cs62	. R language
cs1	Kannan	cs25	Python Programming
cs2	Gowri Shankar	cs28	Big Data
cs2	Gowri Shankar	cs’62	R language
cs2	Gowri Shankar	cs25	Python Programming
cs4	Padmaja	cs28	Big Data
cs4	Padmaja	cs62	R language
cs4	Padmaja	cs25	Python Programming

Question 4.
Explain the Object Model with an example.
Answer:
Object Model:

• Object model stores the data in the form of objects, attributes and methods, classes and inheritance.
• This model handles more complex applications, such as Geographic Information System (GIS), scientific experiments, engineering design and manufacturing.
• It is used in file Management System.
• It represents real-world objects, attributes and behaviours.
• It provides a clear modular structure.
• It is easy to maintain and modify the existing code.

An example of the Object model is : Shape

Circle, Rectangle, and Triangle are all objects in this model

• The circle has the attribute radius.
• Rectangle has the length and breadth of the attribute.
• Triangle has the attributes base and height.
• The objects Circle, Rectangle, and Triangle inherit from the object Shape.

Question 5.
Write a note on different types of DBMS users.
Answer:
Types of DBMS Users
(i) Database Administrator:
Database Administrator or DBA is the one who manages the complete database management system. DBA takes care of the security of the DBMS, managing the license keys, managing user accounts and access etc.

(ii) Application Programmers or Software Developers:
This user group is involved in developing and designing the parts of DBMS.

(iii) End User:
End users are the ones who stores, retrieve, update and delete data.

(iv) Database designers: are responsible for identifying the data to be stored in the database for choosing appropriate structures to represent and store the data.

IV. Answer the following questions (5 Marks)

Question 1.
Explain the different types of data models.
Answer:
The different types of a Data Model are:

1. Hierarchical Model,
2. Relational Model,
3. Network Database Model,
4. Entity-Relationship Model,
5. Object Model.

Hierarchical Model:

• The hierarchical model was developed by IBM as Information Management System.
• In the Hierarchical model, data is represented as a simple tree-like structure form.
• This model represents a one-to-many relationship i.e., parent-child relationship.
• One child can have only one parent but one parent can have many children.
• This model is mainly used in IBM Main Frame computers.

Relational Model:

• The Relational Database model was first proposed by E.F. Codd in 1970.
• Nowadays, it is the most widespread data model used for database applications around the world.
• The basic structure of data in the relational model is tabling (relations).
• All the information related to a particular type is stored in rows of that table.
• Hence tables are also known as relations in a relational model.
• A relation key is an attribute that uniquely identifies a particular tuple (row in a relation (table)).

Network Model:
A network database model is an extended form of the hierarchical data model.
The difference between hierarchical and Network data model is:

• In a hierarchical model, a child record has only one parent node,
• In a Network model, a child may have many parent nodes.
• It represents the data in many-to-many relationships.
• This model is easier and faster to access the data.

Example:

• School represents the parent node
• Library, Office, and Staffroom is a child to school (parent node)
• Student is a child in the library, office and staff room (one to many relationships)

Entity-Relationship Model. (ER model):

• In this database model, relationships are created by dividing the object into the entity and its characteristics into attributes.
• It was developed by Chen in 1976.
• This model is useful in developing a conceptual design for the database.
• It is very simple and easy to design a logical view of data.
• The developer can easily understand the system by looking at ER model constructed.
• The rectangle represents the entities.

Example. Doctor and Patient.

• Ellipse represents the attributes
  E.g. D-id, D-name, P-id, P-name.
• Attributes describe the characteristics and each entity becomes a major part of the data stored in the database.
• The diamond represents the relationship in ER diagrams e.g; Doctor diagnosis the Patient

Object Model:

• Object model stores the data in the form of objects, attributes, and methods, classes, and Inheritance.
• This model handles more complex applications, such as Geographic Information System (GIS), scientific experiments, engineering design, and manufacturing.
• It is used in the file Management System.
• It represents real-world objects, attributes, and behaviours.
• It provides a clear modular structure. It is easy to maintain and modify the existing code.

Example of the Object model is Shape,
Circle, Rectangle and Triangle are all objects in this model

• The circle has the attribute radius.
• Rectangle has the length and breadth of the attribute.
• Triangle has the attributes base and height.
• The objects Circle, Rectangle, and Triangle inherit from the object Shape.

Question 2.
Explain the different types of relationship mapping.
Answer:
The types of relationships used in a database are

• One-to-One Relationship
• One-to-Many Relationship
• Many-to-One Relationship
• Many-to-Many Relationship

One-to-One Relationship:

• In One-to-One Relationship, one entity is related with only one other entity.
• One row in a table is linked with only one row in another table and vice versa. Example: A student can have only one exam number.

One-to-Many Relationship:

• In a One-to-Many relationship, one entity is related to many other entities.
• One row in table A is linked to many rows in table B, but one row in table B is linked to only one row in table A. Example: One Department has many staff members.

Many to-one Relationship

• In Many-to-One Relationship, many entities can be related with only one in the other entity.
• Example: A number of staff members working in one Department. Multiple rows in staff members table is related with only one row in Department table.

Many-to-Many Relationship:

• A many-to-many relationships occurs when multiple records in a table are associated with multiple records in another table.
• Example 1: Customers and Product

Customers can purchase various products and Products can be purchased by many customers.

Example 2: Students and Courses
A student can register for many Courses and a Course may include many students

Example 3: Books and Student.
Many Books in a Library are issued to many students.

Question 3.
Differentiate DBMS and RDBMS.
Answer:

Basis of Comparison	DBMS	RDBMS
Expansion	Database Management System	Relational Database Management System
Data storage	Navigational model ie data by linked records	Relational model (in tables), ie data in tables as row and column
Data redundancy	Exhibit	Not Present
Normalization	Not performed	RDBMS uses normalization to reduce redundancy
Data access	Consumes more time	Faster, compared to DBMS.
Keys and indexes	Does not use.	used to establish a relationship. Keys are used in RDBMS.
Transaction management	Inefficient, Error-prone, and insecure	Efficient and secure.
Distributed Databases	Not supported	Supported by RDBMS.
Example	Dbase, FoxPro.	SQL Server, Oracle, MySQL, MariaDB, SQLite.

Question 4.
Explain the different operators in Relational algebra with suitable examples.
Answer:
Relational Algebra is divided into various groups:
Unary Relational Operations:

1. SELECT (symbol: σ)
2. PROJECT (symbol: π)

Relational Algebra Operations from Set Theory:

1. UNION (U)
2. INTERSECTION (∩)
3. DIFFERENCE (-)
4. CARTESIAN PRODUCT (X)

SELECT symbol: σ_c (R) with a relation R and a condition C on the attributes of R

• The SELECT operation is used for selecting a subset with tuples according to a given condition.
• Select filters out all tuples that do not satisfy C

Table A : STUDENT :

Studno	Name	Course	Year
cs1	Kannan	Big Data	II
cs2	Gowri Shankar	R Language	I
cs3	Lenin	Big Data	I
cs4	Padmaja	Python Programming	I

σ_course = <Big Data> (Student)

Studno	Name	Course	Year
csl	Kannan	Big Data	II
cs2	Lenin	Big Data	I

PROJECT (symbol: n):

• The projection eliminates all attributes of the input relation but those mentioned in the projection list.
• The projection method defines a relation that contains a vertical subset of Relation.
• Example 1 using Table A
  π_course (STUDENT)

Result:

Course :

Big Data

R language

Python Programming

Example 2 (using Table A)
π_{student, course} (STUDENT)

Studno	Course
cs1	Big Data
cs2	R language
cs3	Big Data
cs4	Python Programming

UNION (Symbol: U):

• It includes all tuples that are in tables A or in B.
• It also eliminates duplicates.
• Set A Union Set B would be expressed as A U B

Example 3
Consider the following tables

Table A
Studno	Name
cs1	Kannan
cs2	Lenin
cs3	Padmaja

Table B
Studno	Name
cs1	Kannan
cs2	Lenin
cs3	Padmaja

Result (A U B)

Table A
Studno	Name
cs1	Kannan
cs2	Gowrishankaran
cs3	Lenin
cs4	Padmaja

SET DIFFERENCE ( Symbol: -):

• The result of A – B, is a relation which includes all tuples that are in A but not in B.
• The attribute name of A has to match with the attribute name in B.
• Example 4 (using Table B):

Result:

Table
Cs4	Padmaja

INTERSECTION (symbol: ∩) A ∩ B:

• INTERSECTION Defines a relation consisting of a set of all tuple that are in both in A and B.
• However, A and B must be union-compatible.

Example 5 (using Table B)

Table A – B
cs1	Kannan
cs3	Lenin

PRODUCT OR CARTESIAN PRODUCT (Symbol: X)

• Cross product is a way of combining two relations. The resulting relation contains, both relations being combined.
• A x B means A times B, where the relation A and B have different attributes.
• This type of operation is helpful to merge columns from two relations.

Table A		‘                   Table B
studno	name	studno	subject
cs1	Kannan	cs28	Big Data
cs2	Gowri Shankar	cs62	R language
cs4	Padmaja	cs25	Python Programming

studno	name	course	subject
csl	Kannan	cs28	Big Data
csl	Kannan	cs62	R language
csl	Kannan	cs25	Python Programming
cs2	Gowri Shankar	cs28	Big Data
cs2	Gowri Shankar	cs62	R language
cs2	Gowri Shankar	cs25	Python Programming
cs4	Padmaja	cs28	Big Data
cs4	Padmaja	cs62	R language
cs4	Padmaja	cs25	Python Programming

Question 5.
Explain the characteristics of DBMS.
Answer:
Characteristics of Database Management system:

Data stored in Table	Data is never directly stored in the database. Data is stored in tables, created inside the database. DBMS also allows having relationships between tables which makes the data more meaningful and connected.
Reduced Redundancy	In the modern world, hard drives are very cheap, but earlier when hard drives were too expensive, unnecessary repetition of data in databases was a big problem But DBMS follows Normalization which divides the data in such a way that repetition is minimum.
Data Consistency	On live data, it is being continuously updated and added, maintaining the consistency of data can become a challenge. But DBMS handles it by itself.
Support Multiple user and Concurrent Access	DBMS allows multiple users to work on it( update, insert, delete data) at the same time and still manages to maintain data consistency.
Query Language	DBMS provides users with a simple query language, using which data can be easily fetched, inserted, deleted, and updated in a database.
Security	The DBMS also takes care of the security of data, protecting the data from unauthorized access. In a typical DBMS, we can create user accounts with different access permissions, using which we can easily secure our data by restricting user access.
DBMS Supports Transac­tions	It allows us to better handle and manage data integrity in real-world applications where multi-threading is extensively used.

12th Computer Science Guide Database Concepts Additional Important Questions and Answers

I. Choose the best answer (1 Mark)

Question 1.
…………………… are raw facts stored in a computer
(a) data
(b) Information
(c) row
(d) tuple
Answer:
(a) data

Question 2.
………………….is an organized collection of data, which can be stored and accessed electronically from a computer system
a) Worksheet
b) Database
c) DBMS
d) Information
Answer:
b) Database

Question 3.
……………………. is a repository collection of related data
(a) data
(b) Information
(c) database
(d) tuple
Answer:
(c) database

Question 4.
In………………….data are organized in a way that, they can be easily accessed, managed, and updated.
a) Database
b) Pointer
c) Structure
d) Object
Answer:
a) Database

Question 5.
………………….allows users to store, process, and analyze data easily.
a) My SQL
c) My SQL SQLite
b) Relational Algebra
d) DBMS
Answer:
d) DBMS

Question 6.
Find the wrong statement about DBMS?
(a) segregation of application program
(b) Maximum data Redundancy
(c) Easy retrieval of data
(d) Reduced development time
Answer:
(b) Maximum data Redundancy

Question 7.
…………………. provides protection and security to the databases
a) MySQL
b) DBMS
c) Oracle
d) Ingress
Answer:
b) DBMS

Question 8.
…………………. can be software or hardware-based, with one sole purpose of storing data.
a) MySQL
b) DBMS
c) Database
d) Ingress
Answer:
c) Database

Question 9.
Which is the language used to write commands to access, insert, update data stored in the database?
(a) DataBase Access Languages
(b) Javascript
(c) Basic
(d) Foxpro
Answer:
(a) DataBase Access Languages

Question 10.
…………………. major components are there in DBMS?
a) Four
b) Three
c) Five
d) Two
Answer:
c) Five

Question 11.
…………………. characteristics of DBMS allows to better handle and manage data integrity
a) Data redundancy
b) Data security
c) DBMS Supports Transactions
d) Data integrity
Answer:
c) DBMS Supports Transactions

Question 12.
…………………. DBMS components that manage databases to take backups, report generation.
a) Software
b) Hardware
c) Data
d) Procedures/Methods
Answer:
d) Procedures/Methods

Question 13.
…………………. in a table represents a record.
a) Row
b) Column
c) File
d) Data
Answer:
a) Row

Question 14.
Which of the following is not a DBMS component?
a) Hardware/ Software
b) Data
c) Procedures
d) Data model
Answer:
d) Data model

Question 15.
Hierarchical Model was developed by ……………………….
(a) Apple
(b) IBM
(c) Microsoft
(d) Macromedia
Answer:
(b) IBM

Question 16.
…………………. is not a type of data model?
a) Hierarchical model
b) Entity-Relationship model
c) Object model
d) Redundancy model
Answer:
d) Redundancy model

Question 17.
…………………. is an extended form of hierarchical data model.
a) ER model
b) Hierarchical mode
c) Network database model
d) Object model
Answer:
c) Network database model

Question 18.
The relational model was developed in the year ……………………..
(a) 1980
(b) 1970
(c) 1965
(d) 1985
Answer:
(b) 1970

Question 19.
The abbreviation of GIS is
a) Global Information System
b) Geographic Information System
c) Global Information Source
d) Geographic Intelligent System
Answer:
b) Geographic Information System

Question 20.
Data is represented as a simple tree-like structure form in the data model
a) Network database
b) Hierarchical model
c) ER model
d) Relational model
Answer:
b) Hierarchical model

Question 21.
ER Model Expand ………………………..
(a) Entry Relation
(b) Entity Relationship
(c) Entire Row
(d) Entity Row
Answer:
(b) Entity Relationship

Question 22.
…………………. takes care of the security of the DBMS, managing the license keys, managing user accounts and access.
a) Database Designer
b) Database Administrator
c) Database Architect
d) Data Analyst
Answer:
b) Database Administrator

Question 23.
The …………………. operation is used for selecting a subset with tuples according
to a given condition.
a) CARTESIAN PRODUCT
b) SELECT
c) Union
d) Intersection
Answer:
b) SELECT

Question 24.
Find the wrongly matched pair.
(a) Entities – Rectangle
(b) Ellipse – attributes
(c) Diamond – relationship
(d) row – square
Answer:
(d) row – square

II. Answer the following questions (2 and 3 Marks)

Question 1.
What is a database?
Answer:

• The database is a repository collection of related data organized in a way that data can be easily accessed, managed, and updated.
• The database can be software or hardware-based, with one sole purpose of storing data.

Question 2.
Write the advantages of DBMS.
Answer:

• Segrega n f application program
• Minimal date duplication or Data Redundancy
• Easy retrieval of data using the Query Language
• Reduced development time and maintenance

Question 3.
Define Data and Information.
Answer:

Data	Information
Data are raw facts stored in a computer	Information is formatted data
Data may contain any character, text, word, or number.	The information allows being utilized in a significant way

Question 4.
Define Table?
Answer:
Table is the entire collection of related data in one table, referred to as a File or Table where the data is organized as row and column.

Question 5.
Define: Database structure
Answer:

• Table is the entire collection of related data in one table, referred to as a File or Table where the data is organized as row and column.
• Each row in a table represents a record, which is a set of data for each database entry.
• Each table column represents a Field, which groups each piece or item of data among the records into specific categories or types of data.

Example: StuNo., StuName, StuAge, StuClass, StuSec.,

• A Table is known as a RELATION S
• A Row is known as a TUPLE S
• A column is known as an ATTRIBUTE

Question 6.
Write a note on relational Algebra?
Answer:
Relational Algebra is a procedural query language used to query the database tables using SQL. Relational algebra operations are performed recursively on a relation (table) to yield output.

Question 7.
What is Data model?
Answer:

• A data model describes how the data can be represented and accessed from the software after complete implementation.
• It is a simple abstraction of a complex real-world data gathering environment.
• The main purpose of the data model is to give an idea of how the final system or software will look after development is completed.

Question 8.
What is Relational Algebra?
Answer:

• Relational Algebra, was first created by Edgar F Codd while at IBM.
• It was used for modeling the data stored in relational databases and defining queries on it.
• Relational Algebra is a procedural query language used to query the database tables using SQL.
• Relational algebra operations are performed recursively on a relation (table) to yield an output.
• The output of these operations is a new relation, which might be formed by one or more input relations.

Question 9.
List the types of data model.
Answer:

• Hierarchical Model
• Relational Model
• Network Database Model
• Entity-Relationship Model
• Object Model

Question 10.
List the types of DBMS users.
Answer:

• Database Administrators (DBA)
• Application or software developers
• End-User
• Database designers

Question 11.
Write short notes on Relational Data Model.
Answer:

• The Relational Database model was first proposed by E.F. Codd in 1970 . Nowadays, it is the most widespread data model used for database applications around the world.
• The basic structure of data in the relational model is tables (relations). All the information related to a particular type is stored in rows of that table. Hence tables are also known as relations in a relational model. A relation key is an attribute which uniquely identifies a particular tuple.

III. Answer the following questions (5 Marks)

Question 1.
Explain the components of DBMS
Answer:
The Database Management System can be divided into five major components namely 1. Hardware, 2. Software, 3. Data, 4. Procedures/Methods
5. Database Access Languages

1. Hardware:
The computer, hard disk, I/O channels for data, and any other physical component involved in the storage of data

2. Software:
This main component is a program that controls everything.
The DBMS software is capable of understanding the Database Access Languages and interprets them into database commands for execution.

3. Data:
It is that resource for which DBMS is designed. DBMS creation is to store and utilize data.

4. Procedures/ Methods:
They are general instructions to use a database management system such as the installation of DBMS, manage databases to take backups, report generation, etc

5. DataBase Access Languages :

• They are the languages used to write commands to access, insert, update and delete data stored in any database.
• Examples of popular DBMS: Dbase, FoxPro

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Computer Applications Guide Pdf Chapter 6 PHP Conditional Statements Text Book Back Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Computer Applications Solutions Chapter 6 PHP Conditional Statements

12th Computer Applications Guide PHP Conditional Statements Text Book Questions and Answers

Part I

Choose The Correct Answers

Question 1.
What will be the output of the following PHP code?
<?php
$x;
if ($x)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
c) error

Question 2.
What will be the output of the following PHP code ?
<?php
$x = 0;
if ($x++)
print “hi”;
else
print “how are u”;
?>
a) hi
b) no output
c) error
d) how are u
Answer:
a) hi

Question 3.
What will be the output of the following PHP code ?
<?php
$x;
if ($x == 0)
print “hi”;
else
print “how are u”;
print “hello”
?>
a) how are uhello
b) hihello
c) hi
d) no output
Answer:
a) how are uhello

Question 4.
Statement which is used to make choice between two options and only option is to be performed is written as
a) if statement
b) if else statement
c) then else statement
d) else one statement
Answer:
b) if else statement

Question 5.
What will be the output of the following PHP code ?
<?php
$a =
if ($a)
print “all”;
if
else
print “some”;
?>
a) all
b) some
c) error
d) no output
Answer:
c) error

Question 6.
What will be the output of the following PHP code ?
<?php
$a = “”;
if ($a)
print “all”;
if
else
print “some”;
?>
a) all
b) some
c) error
d) no output

Question 7.
What will be the output of the following PHP code ?
<?php
$x = 10;
$y = 20;
if ($x > $y + $y != 3)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
b) hi

Question 8.
What will be the output of the following PHP code ?
<?php
$x = 10;
$y = 20;
if ($x > $y && 1||1)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
b) hi

Question 9.
What will be the output of the following PHP code ?
<?php
if (-100)
print “hi”;
else
print “how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
a) how are u

Part II

Short Answers

Question 1.
Define Conditional Statements in PHP
Answer:
Conditional statements are useful for writing decision-making logics. It is the most important feature of many programming languages, including PHP. They are implemented by the following types:

1. if Statement
2. if…else Statement
3. if…else if….else Statement
4. switch Statement

Question 2.
Define if statement in PHP.
Answer:
If a statement executes a statement or a group of statements if a specific condition is satisfied as per the user expectation.
Syntax:
if (condition)
{
Execute statement(s) if condition is true;
}

Question 3.
What is an if-else statement in PHP?
Answer:
If else statement in PHP:

1. If a statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation.
2. When the condition gets false (fail) the else block is executed.

Syntax:
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

Question 4.
List out Conditional Statements in PHP.
Answer:

• if Statement
• if…else Statement
• if…else if….else Statement
• switch Statement

Question 5.
Write Syntax of the If else statement in PHP.
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

Question 6.
Define if…elseif….else Statement in PHP.
Answer:

• If-elseif-else statement is a combination of if-else statement.
• More than one statement can execute the condition based on user needs.

Question 7.
Usage of Switch Statement in PHP.
Answer:

• The switch statement is used to perform different actions based on different conditions.
• Switch statements work the same as if statements but they can check for multiple values at a time.

Question 8.
Write Syntax of the Switch statement.
Answer:
switch (n)
{
case label1:
code to be executed if n=la bel1;
break;
case Iabel2:
code to be executed if n=label2;
break;
case label3:
code to be executed if n=iabel3;
break;
…
default:
code to be executed if n is different from all labels;
}

Question 9.
Compare if and if-else statement.
Answer:

If Statement	If else Statement
if statement checks a condition and exe­cutes a set of state­ments when this con­dition is true, it does not do anything when the condition is false.	if-else statement checks a condition and executes a set of statements when this condition is true, it executes another set of statements when the condition is false.

Part III

Explain in brief answer

Question 1.
Write the features Conditional Statements in PHP.
Answer:
PHP Conditional statements:

1. Conditional statements are useful for writing decision-making logics.
2. It is most important feature of many programming languages, including PHP.
3. They are implemented by the following types:
4. if Statement
5. if…else Statement
6. if…elseif….else Statement
7. switch Statement

Question 2.
Write is the purpose of if elseif else stament.
Answer:

• A user can decide among multiple options.
• The if statements are executed from the top I down.
• As soon as one of the conditions controlling the if is true, the statement associated with that if is executed, and the rest of the ladder is bypassed.
• If none of the conditions is true, then the final else statement will be executed.
• More than one statement can execute the condition based on user needs.

Question 3.
Differentiate Switch and if-else statement.
Answer:

Switch statement	if-else statement
Switch statement uses single expression for multiple choices.	the if-else statement uses multiple statements for multiple choices.
Switch statement test only for equality.	if-else statement test for equality as well as for logical expression.
Switch statement execute one case af­ter another till a break statement is appeared or the end of switch statement is reached.	Either if statement will be executed or else statement is executed.

Question 4.
Write Short notes on the Switch statement.
Answer:

1. The switch statement is used to perform different actions based on different conditions.
2. It tests for equality only.
3. It uses default value when all the case values are not matched.
4. It can have multiple ease values.

Question 5.
Differentiate if statement and if-else statement.
Answer:

If statement	if else if else stamen
If-else if-else statement is a combination of if-else statement.	It consists of a single “if statement”. There is no “else” statement here.
More than one state­ment can execute the condition based on user needs	Only one statement can execute
If the condition is false, there are more alterna­tives are there	If the condition is false, there is no alternatives

Part IV

Explain in detail

Question 1.
Explain Functions of Conditional Statements in PHP.
Answer:
Function Conditional Statements:

1. Function conditional statement is the function specified inside the conditional statements.
2. We can’t call a conditional function before its definition.

Syntax:
if(expression)
{
function function_name( )
{
block of statements;
}
}
function_name( ); // calling function.
Eg:
<? php
display( );
if(TRUE)
{
function display( )
{
echo “condition and function”;
}
}
Output: condition and function

Question 2.
Discuss in detail about Switch statement with an example.
Answer:

• The switch statement is used to perform different actions based on different conditions.
• Switch statement test only for equality.
• Switch statement execute one case after another till a break statement has appeared or the end of the switch statement is reached.

Syntax;
switch (n)
{
case label 1:
code to be executed if n=label1;
break;
case label 2:
code to be executed If n=label2;
break;
case label3:
code to be executed if n=label3;
break;
…
default:
code to be executed if n is different from all labels;
}

Example;
<?php
$favcolor = “red”;
switch ($favco!or) {
case “red”:
echo “Your favorite color is red!”;
break;
case “blue”:
echo “Your favorite color is blue!”;
break;
case “green”:
echo “Your favorite color is green!”;
break;
default:
echo “Your favorite color is neither red, blue, nor green!”;
}
?>

Question 3.
Explain the process of Conditional Statements in PHP?
Answer:
Conditional statements are useful for writing decision-making logics. It is the most important feature of many programming languages, including PHP. They are implemented by the following types:

(i) if Statement:
If statement executes a statement or a group of statements if a specific condition is satisfied as per the user expectation.

(ii) if…else Statement:
If statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation. When the condition gets false (fail) the else block is executed.

(iii) if…elseif….else Statement:
If-elseif-else statement is a combination of if-else statement. More than one statement can execute the condition based on user needs.

(iv) Switch Case:
The switch statement is used to perform different actions based on different conditions.

Question 4.
Explain concepts of if elseif else statement.
Answer:

• If-elseif-else statement is a combination of if-else statement.
• More than one statement can execute the condition based on user needs.

Syntax:
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2ndcondition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

Example Program:
<?php
$Pass_Mark=35;
$first_class=60;
$Student_Mark=70;
if ($Student_Mark>= $first_class){ echo “The Student is eligible for the promotion with First Class”;
}
elseif ($Student_Mark>= $Pass_Mark){ echo “The Student is eligible for the promotion”;
}
else {
echo “The Student is not eligible for the promotion”;
}?>

Question 5.
Explain the if-else statement in PHP.
Answer:
If else statement in PHP:
If a statement executes a statement or a group of statements if a specific condition is satisfied by the user expectation. When the condition gets false (fail) the else block is executed.
Syntax:
if (condition)
{
Execute statement(s) if condition is true;
} else
{
Execute statement(s) if condition is false;
}
Example:
<?php
$Pass_Mark=35;
$Student_Mark=70;
if ($Student_Mark>= $Pass_Mark)
{
echo “The Student is eligible for the promotion”;
}
else
{
echo “The Student is not eligible for the promotion”; }
?>

12th Computer Applications Guide PHP Conditional Statements Additional Important Questions and Answers

Part A

Choose The Correct Answers:

Question 1.
How many types of PHP conditional statements are there?
(a) 2
(b) 3
(c) 4
(d) 5
Answer:
(c) 4

Question 2.
What will be the output of the following PHP code ?
<?php
if(0.0)
print”hi”;
else
print”how are u”;
?>
a) how are u
b) hi
c) error
d) no output
Answer:
a) how are u

Question 3.
The ……………………….. statement is used to perform different actions based on different conditions.
Answer:
switch

Question 4.
What will be the output of the following PHP code ?
<?php
$a=”l”;
switch($a)
{
case1:
break;
print”hi”;
case2:
print’tiello”;
break;
default:
print”hil”;
>
?>
a) hihellohi1
b) hi
c) hihi1
d) hi1
Answer:
a) hihellohi1

Question 5.
What will be the output of the following PHP code ?
<?php
$x=l;
if($x=$x&0)
print$x;
else
break;
?>
a) 0
b) 1
c) error
d) no output
Answer:
c) error

Question 6.
Which of the following can check for multiple values at a time?
(a) If
(b) If else
(c) Nested else
(d) Switch
Answer:
(d) Switch

Very Short Answers

Question 1.
How conditional statements perform?
Answer:
It performs different actions for different decisions in programing language

Question 2.
What is an “if statement” in PHP?
Answer:
The If Statement is a way to make decisions based upon the result of a condition.

Question 3.
How switch statement and if statement differs?
Answer:
Switch statements work the same as if statements but they can check for multiple values at a time

Match the following:

1. Simple if statements – Multiple branching
2. If-else statement – Combination of if-else statement
3. If elseif else statement – Only one option
4. Switch case statement – Alternative statement

Part B

Short Answers

Question 1.
Write the syntax of the If statement.
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}

Question 2.
What is mean by If else ladder?
Answer:

• Else executes the following block of statements if the condition in the corresponding if is false.
• After the else, if another condition is to be checked, then an if statement follows the else. This is else if and is called as if-else ladder.

SYNTAX:

1. If statement
Answer:
if (condition)
{
Execute statement(s) if condition is true;
}

2. If else statement
if (condition)
{
Execute statement(s) if condition is true;
}
else
{
Execute statement(s) if condition is false;
}

3. If elseif else statement
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2ndcondition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

4. Switch Case:
switch (n) { case label 1:
code to be executed if n=label1;
break;
case Iabel2:
code to be executed if n=label2;
break;
case Iabel3:
code to be executed if n=label3;
break;
…
default:
code to be executed if n is different from all labels;
}

Part C

Explain in brief answer

Question 1.
Give the Syntax for If else statements in PHP?
Answer:
if (1st condition)
{
Execute statement(s) if condition is true;
}
elseif(2nd condition)
{
Execute statement(s) if 2nd condition is true;
}
else
{
Execute statement(s) if both conditions are false;
}

Programs

Question 1.
Write a php program to birthday greetings using if statement.
Answer:
<?php
$date=date(“m-d”);
if ($date==»01T0»)
{
echo “Wishing you a very Happy Birthday”;
}
?>

Question 2.
Write a php program to check whether the given number is positive or negative.
Answer:
<?php
$x = -12;
if ($x > 0)
{
echo “The number is positive”;
}
else{
echo “The number is negative”;
}
?>

Question 3.
Write a PHP program to display independence day and republic day the greetings using If elseif else statement
Answer:
<?php
$x = “August”;
if ($x == “January”) {
echo “Happy Republic Day”;
}
elseif ($x == “August”) {
echo “Happy Independence Day!!!”;
}
else{
echo “Nothing to show”;
}
?>

Part D

Explain in detail

Question 1.
Write a PHP code to display the days of weak using switch statement
Answer:
<?php
$today=date(“D”);
switch($today)
{
case”Mon”:
echo’Today is Monday.
break;
case”Tue”:
echo’Today is Tuesday.”;
break;
case”Wed”:
echo’Today is Wednesday.”;
break;
case’Thu”:echo’Today is Thursday.”;
break;
case”Fri”:
echo’Today is Friday. Party tonight.”;
break;
case”Sat”:echo’Today is Saturday.”;
break;
case”Sun”:
echo’Today is Sunday.”;
break;
default:
echo”No information available for that day.”;
break;
}
?>

Question 2.
Write a PHP program to display week days using switch case statement.
Answer:
<?php
$n = “February”;
switch($n) {
case “January”:
echo “Its January”;
break;
case “February”:
echo “Its February”;
break;
case “March”:
echo “Its March”;
break;
case “April”:
echo “Its April”;
break;
case “May”:
echo “Its May”;
break;
case “June”:
echo “Its June”;
break;
case “July”:
echo “Its July”;
break;
case “August”:
echo “Its August”;
break;
case “September”:
echo “Its September”;
break;
case “October”:
echo “Its October”;
break;
case “November”:
echo “Its November”;
break;
case “December”:
echo “Its December”;
break;
default:
echo “Doesn’t exist”;
}
?>

Tamilnadu State Board New Syllabus Samacheer Kalvi 12th Maths Guide Pdf Chapter 5 Two Dimensional Analytical Geometry – II Ex 5.4 Textbook Questions and Answers, Notes.

Tamilnadu Samacheer Kalvi 12th Maths Solutions Chapter 5 Two Dimensional Analytical Geometry – II Ex 5.4

Question 1.
Find the equations of the two tangents that can be drawn from (5, 2) to the ellipse 2x² + 7y² = 14.
Solution:
2x² + 7y² = 14
(÷ by 14) ⇒ \(\frac{x^{2}}{7}+\frac{y^{2}}{2}\) = 1
comparing this equation with \(\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}\) = 1
we get a² = 7 and b² = 2
The equation of tangent to the above ellipse will be of the form
y = mx + \(\sqrt{a^{2} m^{2}+b^{2}}\) ⇒ y = mx + \(\sqrt{7 m^{2}+2}\)
Here the tangents are drawn from the point (5, 2)
⇒ 2 = 5m + \(\sqrt{7 m^{2}+2}\) ⇒ 2 – 5m = \(\sqrt{7 m^{2}+2}\)
Squaring on both sides we get
(2 – 5m)² = 7m² + 2
25m² + 4 – 20m – 7m² – 2 = 0
18m² – 20m + 2 = 0
(÷ by 2) ⇒ 9m² – 10m + 1 = 0
(9m – 1) (m – 1) = 0
‘ m = 1 (or) m = 1/9
When m = 1, the equation of tangent is
y = x + 3 or x – y + 3 = 0
When m = \(\frac{1}{9}\) the equation of tangent is 9
y = \(=\frac{x}{9}+\sqrt{\frac{7}{81}+2}\) (i.e.) y = \(\frac{x}{9}+\frac{13}{9}\)
9y = x + 13 or x – 9y + 13 = 0

Question 2.
Find the equations of tangents to the hyperbola \(\frac {x^2}{16}\) – \(\frac {y^2}{64}\) = 1 which are parallel to 10x – 3y + 9 = 0.
Solution:
Equation of Hyperbola \(\frac {x^2}{16}\) – \(\frac {y^2}{64}\) = 1
∴ a² = 16, b² = 64
Tangent is parallel to the line
10x – 3y + 9 = 0 is
10x – 3y + k = 0
∴ 3y = 10x + k
y = \(\frac {10}{3}\)x + \(\frac {k}{3}\)
∴ m = \(\frac {10}{3}\) c = \(\frac {k}{3}\)
Condition that the line y = mx + c to be tangent to the hyperbola is
c² = a²m² – b²

k² = 1024
k = ±32
∴ Equation of tangent
⇒ 10x – 3y ± 32 = 0

Question 3.
Show that the line x – y + 4 = 0 is a tangent to the ellipse x² + 3y² = 12. Also find the co-ordinates of the point of contact.
Solution:
The given ellipse is x² + 3y² = 12
(÷ by 12) ⇒ \(\frac{x^{2}}{12}+\frac{y^{2}}{4}\) = 1
(ie.,) Here a² = 12 and b² = 4
The given line is x – y + 4 = 0
(ie.,) y = x + 4
Comparing this line with y = mx + c
We get m = 1 and c = 4
The condition for the line y = mx + c
To be a tangent to the ellipse \(\frac{x^{2}}{a^{2}}+\frac{y^{2}}{b^{2}}\) = 1 is c² = a²m² + b²
LHS = c² = 4² = 16
RHS: a²m² + b² = 12( 1 )² + 4 = 16
LHS = RHS The given line is a tangent to the ellipse. Also the point of contact is
\(\left(\frac{-a^{2} m}{c}, \frac{b^{2}}{c}\right)=\left[-\left(\frac{12(1)}{4}\right), \frac{4}{4}\right]\) (i.e.,) (-3, 1)

Question 4.
Find the equation of the tangent to the parabola y² = 16x perpendicular to 2x + 2y + 3 = 0.
Solution:
Equation of the parabola
y² = 16x
4 a = 16
a = 4
Tangent is perpendicular to the line
2x + 2y + 3 = 0 is 2x – 2y + k = 0
2x – 2y + k = 0
2y = 2x + k
y = x + \(\frac {k}{2}\)
m = 1 c = \(\frac {k}{2}\)
Condition that the line y = mx + c to be tangent to the parabola is
c = \(\frac {a}{m}\)
\(\frac {k}{2}\) = \(\frac {4}{1}\)
k = 8
Equation of the tangent
2x – 2y + 8 = 0
÷ by 2 ⇒ x – y + 4 = 0

Question 5.
Find the equation of the tangent at t = 2 to the parabola y² = 8x (Hint: use parametric form).
Solution:
y² = 8x
Comparing this equation with y² = 4ax
we get 4a = 8 ⇒ a = 2
Now, the parametric form for y² = 4ax is x = at², y = 2at
Here a = 2 and t = 2
⇒ x = 2(2)² = 8 and y = 2(2) (2) = 8
So the point is (8, 8)
Now eqution of tangent to y² = 4 ax at (x₁, y₁) is yy₁ = 2a(x + x₁)
Here (x₁, y₁) = (8, 8) and a = 2
So equation of tangent is y(8) = 2(2) (x + 8)
(ie.,) 8y = 4 (x + 8)
(÷ by 4) ⇒ 2y = x + 8 ⇒ x – 2y + 8 = 0
Aliter
The equation of tangent to the parabola y² = 4ax at ‘t’ is
yt = x + at²
Here t = 2 and a = 2
So equation of tangent is
(i.e.,) y(2) = x + 2(2)²
2y = x + 8 ⇒ x – 2y + 8 = 0

Question 6.
Find the equations of the tangent and normal to hyperbola 12x² – 9y² = 108 at θ = \(\frac {π}{3}\) .
(Hint: use parametric form)
Solution:
(i) Equation of the tangent to hyperbola be

⇒ 4x – 3y = 6
⇒ 4x – 3y – 6 = 0

(ii) Equation of the normal to hyperbola be

⇒ 3x + 4y – 42 = 0

Question 7.
Prove that the point of intersection of the tangents at ‘t₁‘ and ‘t₂‘ on the parabola y² = 4ax is [at₁t₂, a(t₁ + t₂)].
Solution:
Equation of the tangent of parabola y² = 4ax be
at t₁ yt₁ = x + at₁² ……….. (1)
at t₂ yt₂ yt = x + at₂² ……….. (2)
(1) – (2) ⇒ y(t₁ – t₂) = a(t₁² – t₂²)
y(t₁ – t₂) = a(t₁ + t₂)(t₁ – t₂)
y = a(t₁ + t₂)
(1) ⇒ t₁a(t₁ + t₂) = x + at₁²
x = at₁² + at₁t₂ – at₁²
x = at₁t₂
Point of intersection be [at₁t₂, a(t₁ + t₂)]

Question 8.
If the normal at the point ‘t₁‘ on the parabola y² = 4ax meets the parabola again at the point t₂ then prove that t₂ = -(t₁ + \(\frac {2}{t_1}\))
Solution:
Equation of normal to y² = 4at’ t’ is y + xt = 2at + at³.
So equation of normal at ‘t₁’ is y + xt₁ = 2at₁ + at₁³
The normal meets the parabola y² = 4ax at ‘t₂’ (ie.,) at (at₂², 2at₂)
⇒ 2at₂ + at₁t₂² = 2at₁ + at₁³
So 2a(t₂ – t₁) = at₁³ – at₁t₂²
⇒ 2a(t₂ – t₁) = at₁(t₁² – t₂²)
⇒ 2(t₂ – t₁) = t₁(t₁ + t₂)(t₁ – t₂)
⇒ 2= -t₁(t₁ + t₂)
⇒ t₁ + t₂ = \(\frac{-2}{t_{1}}\)
⇒ t₂ = \(-t_{1}-\frac{2}{t_{1}}=-\left(t_{1}+\frac{2}{t_{1}}\right)\)