Touchpad Computer Applications Class 9

By Sanjay Jain

The chapters of this book have been selected and designed as per the CBSE curriculum of Computer Applications (Code 165).

KEY FEATURES
- National Education Policy 2020
- Do you Know?: This section contains a fact about the topic.
- Lab Assignment 'N Activity: This section contains an activity to apply the concepts learnt.
- PART A & PART B: This section contains questions to assess the intellectual and comprehensive writing skills.
- Sample Question Paper: This section contains sample question paper.
- Digital Solutions

DESCRIPTION (This section should contain complete information about the book from the start to the end, in around 1350 characters with space.)
The main features of this book are as follows:
- The language of the book is simple and easy to understand.
- The book focuses on Free and Open-Source Software (Foss) with highlights of MS Office.
- Notes are given for add-on knowledge.
- Students are provided with fun facts about the topic.
- Lab Activities are added in between the chapters to develop practical skills.
- The applications of IT Tools are discussed with real life scenarios.
- The contents will help to create opportunity for better job prospects with respect to IT fields.

WHAT WILL YOU LEARN (what will the readers be capable of doing after reading the book)(5-6 sentences) (300 characters with space)
You will learn about:
- Fundamentals of computers
- ICT Tools
- Word Processing
- Handling Spreadsheets
- Creating Presentation
- Writing basic Python/Scratch Program

WHO THIS BOOK IS FOR (audience) (Let the readers know what knowledge they should have before reading the book)(350 characters with space)
Grade - 9

TABLE OF CONTENTS (Numbered list)
1. Unit-1: Basics of Information Technology
(a) Chapter-1 Basics of Information Technology
2. Unit-2: Cyber Safety
(a) Chapter-2 Cyber Safety
3. Unit-3: Office Tools
(a) Chapter-3 Working with Word Processor
(b) Chapter-4 Working with Presentation
(c) Chapter-5 Effects in Presentation
(d) Chapter-6 Working with Spreadsheet
(e) Chapter-7 Data Analysis
4. Unit-4: Scratch or Python
(a) Chapter-8 Scratch
(b) Chapter-9 Animation in Scratch
(c) Chapter-10 Python
5. Practical Work
6. Viva Voce Questions
7. Projects
8. Glossary
9. Sample Question Paper

• Language: English
• Publisher: Orange Education Pvt Ltd
• Release date: Nov 1, 2021
• ISBN: 9789390475377

Book preview

Unit-1: BASICS OF INFORMATION TECHNOLOGY

1

BASICS OF INFORMATION TECHNOLOGY

With the advent of computers, extraordinary development has taken place in the field of information and appliances of communication, which has given rise to the era of Information Technology (IT).

Information Technology has led to the establishment of a global network and has brought people from different corners of the world to connect with each other. It allows anytime anywhere access and instant sharing of data/information. IT has laid a great impact on our society.

Information Technology is the use of computers to gather, process, store, protect and transfer information. Modern computers are a storehouse of augmenting information.

‘A computer is an electronic device which performs numerical calculations (+,-, *, /) and logical operations (AND, OR, NOT) at high speed and produces information that are expressible in numerical as well as in logical form’.

A computer is an electronic machine that accepts data and processes it to produce meaningful results & accomplish various tasks.

DESIGN OF COMPUTER

A computer performs action and accomplishes its tasks in three basic stages namely: Input, Process and Output. It works according to a set of pre-defined programs. A program is a set of sequentially arranged instructions which directs the computer to process the input, in order to produce the required output or result.

Input is the data that is fed to the computer by the user. Some examples of input are numbers for calculation, marks of students of a class, etc.

Processing refers to the series of actions by which the computer converts raw data into meaningful result. Processing of data is done in the CPU.

Output is the final result produced, which is also termed as information. Some examples of output are graphs, mark sheets, reports, animated movies, etc.

Data is a collection of raw facts and figures which are fed to the computer in the form of Input. Process is the series of actions performed on the data to convert it into meaningful result as per the given instructions. Information is the result produced by the computer in the form of output.

CHARACTERISTICS OF A COMPUTER

A computer is a wonderful electronic machine and it has many significant features which make it a multi-purpose device. The special characteristics that make it such a popular and useful machine are:

Speed: A computer works at a very high speed. It can execute millions of instructions in a second. Its speed is measured in Hertz i.e., Hz (KHz, MHz, GHz, etc.). A modern computer can perform calculations in ‘Nano Second’ or ‘Pico Second’.

Accuracy: A computer performs its tasks accurately. It performs calculations without making mistakes and produces information in accordance to the data entered.

Reliability: A computer is a reliable device, it does not fail to produce accurate results. It works exactly as per the given instructions. It can even work in severe conditions, where human beings cannot work.

Versatility: A computer is versatile in nature i.e., it can work on various kinds of inputs and can produce multiple kinds of outputs like sounds, graphics, texts, animations, etc. It is a single machine capable of performing hundreds of different tasks.

Storage Capacity: A computer has a very huge memory. It can store large volumes of data in a small sized hardware device, which can be retrieved as and when required. The unit of storage of data is known as Byte.

Diligence: A computer is free from problems such as tiredness, monotony or lack of concentration that humans face. It can work for many hours at a stretch. It can perform the same task repeatedly on a similar or dissimilar data without any error, tiredness or boredom.

Logical Ability: A computer is capable of comparing all types of data, like numeric or non-numeric and it can even take logical decisions as per the given instructions.

Flexibility/Multitasking: During its operation, a computer can perform multiple tasks at the same time. It allows the user to switch from one application to another at any point of time.

Transfer of Data: We can also transfer data from one computer to another through external storage devices like Pen Drive, CD, DVD, Blu-ray disc or via networks.

LIMITATIONS OF A COMPUTER

There are certain limitations of a computer which are given below:

Apathetic: Computer has no sentiments.

Zero IQ: Computer has no IQ. It cannot think on its own, it has to be guided or instructed by the user.

Non Heuristic: Computer has only Artificial Intelligence. It cannot learn from its past experiences.

Dependency: Computers are dependent on user’s input or instructions to work and take decisions.

COMMUNICATION TECHNOLOGY

Communication refers to transfer of ideas or information from one place to another between different individuals. It means establishing links between places or people to share information and resources amongst each other.

Traditionally, there have been many types of media and services of communications like Postal services, TV, Podcast, Radio, Telephones, etc. which are regulated by different governing bodies.

The convergence of technologies has led to the development of digital communication that has made it possible for organizations and individuals to transfer or deliver text, audio and video materials over the wired, wireless or fiber-optic connections.

The digital technology has a far-reaching impact on the nature and speed of communication. With the use of computers and internet connection, data can be instantly transferred from one corner of the world to the other.

Any sort of communication involves a sender, a receiver and a communication channel.

‘Sender’ is the one who sends data, i.e., the ‘Source’ of information.

‘Receiver’ is the one who receives data, i.e., the ‘Destination’ of information.

‘Communication Channel’ is the media through which data is transferred (i.e., air, wires, waves, satellite connections, etc.) from sender to receiver and vice versa.

When the communication is established or resources are shared between multiple users at different places then the communicating devices or users are said to be in a ‘Network’.

COMPONENTS OF A COMPUTER SYSTEM

A computer system functions with the help of ‘Hardware’ and ‘Software’ components. The physical components, which can be touched or felt are called the hardware components, whereas the components which cannot be touched or felt, such as instructions, data etc. form the software component of the system. Keyboard, Mouse etc. are hardware & MS Word, Windows etc. are software.

Hardware is the electro-mechanical part of a computer that is capable of computing and manipulating information, whereas software is a collection of instructions or programs which directs and coordinates the functions of computing and manipulating. Software is portable which means it can be easily moved from one device to the other, whereas hardware cannot be transferred easily from one place to the other. Hardware is easily replaceable, but software is not.

A computer is an instruction driven device that accepts data, processes it and produces the desired results in the form of information. Data are fed into the computer through the ‘Input’ devices which are then ‘Processed’ inside the CPU and then results are displayed through the ‘Output’ devices. Thus, a computer system constitute of input devices, output devices and processing device.

Input Devices

There are various types of input devices. Some of the common input devices are Keyboard, Mouse, Joystick, Scanner, OMR, OCR, MICR, Light Pen, Microphone, Bar Code Readers, Web Camera, Digital Camera, etc.

Keyboard

Keyboard is the standard input device. It is mainly used to type text and to send the instructions to a computer with the help of keys. Keys are the buttons on the keyboard that represent alphabets, numerics, alphanumerics and special characters. The keys can be used individually or in combination with other keys. The keyboard normally contains 101 to 108 keys.

Depending on the position or placement of the keys, the layout of a keyboard comes in various styles such as QWERTY, QWERTZ, AZERTY and DVORAK. QWERTY keyboard is the most commonly used keyboard. It is based on the English Language. Its name is derived from the sequence of the six alphabetical keys positioned on the upper row of the keyboard. AZERTY type keyboard is mostly used in France (‘A’ and ‘Z’ characters replace ‘Q’ and ‘W’ on such keyboards). QWERTZ type keyboard is widely used in Germany and Central Europe.

Mouse

Mouse is a hand-held device which is used on a flat surface and is represented by a pointer on the screen. The pointer on the screen moves when the mouse is moved by the user. A mouse generally consists of two buttons and a scroll wheel on its top.

By pressing (clicking) the buttons of the mouse, the user gives instructions to the computer. The mouse was invented by Douglas Engelbart.

The most commonly used mouse nowadays is the optical mouse. It has no moving parts and uses LED (Light emitting diode) to detect the movement.

Joystick

Joystick is a pointing device whose function is similar to a mouse, except that a mouse pointer stops moving on the screen as soon as the user stops moving it, while the joystick pointer continues to move in the direction towards which the joystick has been pointed.

To stop the pointer, the user has to bring the joystick to its upright position. It is generally used to play video games.

Scanner

A scanner is a device that scans a document by sensing the reflection that is received when the scanner emits rays on the content. It takes the image of content and converts it into a digital file.

The scanned images or photos can be stored in a computer and can be easily transferred to a secondary storage device. Scanners can be categorized as ‘Hand held scanner’ and ‘Flatbed scanner’.

Optical Mark Reader (OMR)

OMR is an input device which can detect the marks on a paper. It is used to evaluate answer sheets in which selected answers are marked in dark circles.

It is used to read or detect marked answers by sensing the marks made on the answer sheet by exposing the sheet to a beam of light.

Magnetic Ink Character Reader (MICR)

MICR is a device which is used by banks for processing cheques by interpreting information stored in MICR code (printed at the bottom of cheque)

On the cheques, the code of name of the bank, branch code and cheque number are printed with a special kind of ink containing magnetic particles or iron oxide which is scanned & read with the help of MICR and accordingly processed in the computer. A MICR code consists of nine (9) digits.

Light Pen

A ‘Light Pen’ is a pen like device which uses a light sensitive detector to select or draw objects on the display screen.

It is similar to a mouse, except that with a light pen one can move the pointer on the screen by touching it to the objects on the screen. When the pen is moved across the screen, its position is sensed because of the light it emits.

Bar Code Reader

A Bar Code Reader is a popular scanning device which reads the bar codes. Bar code comprises of adjacent vertical black bars of different width. A barcode stores information about a product, eg: its price, weight, manufacturing details etc.

Bars are codes that represent different numbers. One can see the bar code on the back cover of this book as well. A bar code reader emits a beam of light (Laser Beam), which reflects the bar code image. A light sensitive detector is present in the bar code reader which identifies and reads the bar code image. The bar pattern is changed into numeric code inside the CPU.

Microphone

A microphone is a voice based input device. With the help of this device, sound or voice is recognized/recorded in the computer and is converted into digital form which is then played or processed by the computer.

Digital Camera

A digital camera captures image or picture momentarily and converts the image directly into digital form and stores in memory. It can then be viewed on the computer or compatible devices.

It is available in various models with different specifications that include pixels, sizes and memory. The quality of image captured by digital camera is measured in pixels.

Web Camera

A web camera or a webcam is a type of video camera that captures images or visuals in real-time & passes data to a computer via USB, ethernet or Wi-Fi. Web cam do not have an inbuilt storage like a digital camera.

Web camera is used to create video links and allows set up of authentic video-conference stations. Some built-in webcams can be remotely activated from far off locations. Webcams can also be used for security & surveillance purposes by monitoring the captured visuals.

Biometric Devices

These devices use the physical characteristics of a living being to authenticate its identity. These devices are capable of scanning hand prints, finger prints, retinal information, facial features etc. to compare with a sample and grant access to an individual to a particular device or information. Example: Used in phones for security and used for attendance tracking in offices.

Processing Device

A CPU (Central Processing Unit) is also known as the ‘Brain of a Computer’. As it appears, it is a hardware component, but it is also an important functional component of a computer system. It does all the processing, calculations and comparisons at a rapid speed. Its speed is measured in higher units of hertz (hz) i.e. 9 MHz. It takes information from the input unit or memory and processes it as per the given instructions. Processing includes calculations, comparisons, decision making, etc.

Some versions of processors are Pentium series, Dual Core, Core 2 Duo, Athlon, IBM Cyrix, Core-i3, Core-i5, Core-i7, AMD Ex Series, etc.

Functional Elements of a CPU

The functional elements of a CPU can be divided into three parts:

Arithmetic Logic Unit (ALU)

Control Unit (CU)

Memory Unit (MU)

Arithmetic Logic Unit (ALU)

An ALU performs mathematical calculations (addition, subtraction, multiplication, division, etc.) and logical comparisons (greater than(>), less than(<), equal to (=), not equal to(!=), etc.). ‘Logical Operation’ refers to a comparison between two phrases that results in ‘TRUE’ or ‘FALSE’ value. It receives the coded data and manipulates them to produce information in machine code and then send to the Control Unit.

Control Unit (CU)

A control unit co-ordinates and directs the operation of the hardware devices. It also co-ordinates the flow and execution of the data and instructions, that are fed into the computer’s memory. CU functions in a F-D-E-S (Fetch-Decode-Execute-Store) cycle. It fetches the instruction and data from the memory unit & decodes them and passes to the ALU for further processing. It also directs the ALU to execute the instructions and performs the required operations on the data.

Memory Unit (MU)

A memory unit or main storage or the internal storage stores the data, instructions, intermediate and the final results that are ready for the output. All instructions or data are stored in the memory unit before being used by the ALU or the CU.

The main storage is divided into a number of storage locations that can be accessed by a unique number or address, known as memory address. Within the CPU, there are high speed, special purpose memory units called registers.

The control unit and the internal storage are linked together by the sets of parallel electrical conducting lines called Buses. The buses that carry data are called ‘Data Buses’. To retrieve data from the memory, it is necessary to