Digital book Class 4 2nd edition

Smart Page Computer Science Book-4 1

Smart Computer Science Book-4 Author Prabhu Ram Khadka M. Sc. IT (SMU), B. Ed. (TU) Memorica Pvt. Ltd. Publishers & Distributors Maitidevi, Katmandu Smart Page Computer Science Book-4 2

Book : Smart Computer Science Book-4 Author : Prabhu Ram Khadka Language Editors : Sharan Ratna Sthapit Shivahari Sapkota Publisher : Memorica Pvt. Ltd. Maitidevi, Kathmandu Ph:01-4438703/9841816625/ 9813303490 Edition : 1st 2077 B.S. (2020 AD) 2nd 2080 B.S. (2023) Copyright : All rights reserved with the author ISBN : 978-9937-9382-5-9 For suggestion and advice please contact at [email protected] Cell : 9841816625, 9813303490 (Viber/Messenger) https://www.facebook.com/prabhuram.khadka.9 URL: www.memoricapublication.com Page  3

About this Book Smart Computer Science is a graded series of ten textbooks prepared for the classes 1 to 10. This series of books is comprehensively designed on the basis of the guidelines and syllabi designed by Government of Nepal, Ministry of education, Curriculum Development Centre. Beginning with the very basic concept of computer, the series gradually introduces more advanced aspects of computing concept, skill and software to students as they go to higher classes. It attempts to include latest software required for the daily working. I hope, this series shall be helpful in the overall development of the computer literacy in the related learners. Salient features • Step by step simple technique and tools • Simple vocabulary and language • Practical approach based • Worksheet based • Logical analysis and case study base for enhancing creativeness • Activity based • Project work based Although I’ve tried my best not to leave print slips as far as possible, some errors may have crept in without noticing. If so that I’d like to request the respected teachers to reach the students correctively. Comments and constructive suggestions from students, teachers and well wishers are always welcome. Constructive advice will be incorporated in the next edition. I duly thank Sharan Ratna Sthapit and Shivahari Sapkota for their contribution on editing of language through out this book. My hearty thanks also go to Mr. Bidhan Khadka for his effort of bringing my work ac- complished. Smart Prabhu Ram Khadka The Author Computer Science Book-4 Page 4

TABLE OF CONTENTS Ch. Title Pg. no. Periods 3 1. Knowing Computer 1-10 2. Evolution of Computer 11-22 3 3. Computer Devices 23-41 3 4. Microsoft Windows 42-57 3 5. Painting & Drawing 58-106 20 6. MS-Word 107-129 5 7. Scratch coding 130-183 20 8. Model Question (Theory) 184-190 9. Model Question (Practical) 191-192 Total Periodss 57 Page  5

CHAPTER Knowing Computer 1 LEARN and ACT Jigme : Hey Mingma! Can you tell me what a computer is? Mingma : Computer is an electronic device which accepts data; processes them and gives output result. Jigme : Can you say some reasons, why computer is called special machine? Mingma : A computer works very fast, gives accurate result, never gets tired, has high storage capacity, etc. So computer is called special machine. Jigme : Does a computer have any weaknesses? Mingma : Yes, computer doesn't have its own intelligence, common sense and it can’t work itself. INTRODUCTION This is the age of computer. Nowadays computers are used almost everywhere. There are big computers as well as handheld small computers. Big computer are used in offices, transportation, educational institution, hospital, communication, etc. Whereas, small computers are used in watches, cars, toys, etc. 'Computer' word is derived from a Latin word ‘Computare’ which means to calculate. It woks on the basis of electric pulses ‘on’ and Smart Page Computer Science Book-4 1

‘off' state. So, computer is defined as an electronic data processing device which accepts data and instructions from the input devices, processes them into processing device, gives output information through the output device and stores them in storage device. BASIC PRINCIPLE OF COMPUTER Lakpa : I do everything in a system. My sense organs receive sensory details from the environment, brain calculates and takes decision and mouth produces speech. Computer : I also work on a similar principle that is Input- Process- Output. Input device receives, processing device calculates and output device gives us information. The computer is a man-made machine. It is designed to work on the basis of certain principles, which are presented in the figure: COMPUTER IS AN IMPORTANT MACHINE Computer provides many benefits to us. The following characteristics of a computer make it important for us. Page Knowing Computer 2

High speed Jigme : Hey Mingma, I know that computer can do sums. I can also do such sums. So, why is a computer needed? Mingma : Oh! You have a point. But tell me how much time do you need to solve a simple sum? Jigme : I need almost 1 to 2 minutes. Mingma : That’s why you need a computer. It can solve a sum in a fraction of a second. It is very fast. Computer works at high speed. It can solve sums in a fraction of a second. It can process millions of instructions per second. Accuracy Jigme : Look here Mingma, I couldn't get the correct answer of this sum. Mingma : Oh! Jigme, you might have made a mistake. Please do it on the computer. Jigme : (Starts to check in the computer). Yes! Now it’s matching. Mingma : Let's look, computer never makes mistake. You can make mistake in the calculation but computer is hundred percent accurate. Smart Page Computer Science Book-4 3

Large Storage Capacity Mingma : Once you read a book, can you store it in the brain? Jigme! Jigme : No, I can’t. Mingma : But computer can store it. Jigme : Wow, It’s wonderful! A computer has high storage capacity. It can store whole Ramayana and Mahabharata volumes in a small disk. Computer Never Forgets Jigme : You taught me many things about the computer. But I have already forgotten some it. Mingma : Doesn't matter. We may forget slowly one by one. But computer never forgets things once stored, even after many years. The data you store in computer’s storage device won't be erased until you delete. So, a computer never forget things. You can retrieve any data or information from computer even after so many years. Diligent Jigme : Hey Mingma! I have done some sums. Now I am getting tired and felling bored. I have to do many more sums. Can you help me? Page Knowing Computer 4

Mingma : Whenever you instruct, computer never fells tired and bored. It can do millions of sums continuously. Human being feels tired and bored after doing certain work. But computer is a machine, due to this, it never gets tired and bored even after doing millions of calculation. Computer constantly gives effort to complete a task. Versatile Mingma : How many unique activities can you do efficiently? Like dancing, swimming, singing, joking, performing magic, etc. Jigme : I can’t do such type of unique activities. I am a painter. I can only paint. Mingma : So, Computer is a special machine. It can do many different unique works. Computer can be used almost everywhere. It can perform different types of work. It can be used to type text to complete complex mathematical calculations. However, human beings can not do many types of work efficiently. So, unlike a man, a computer is versatile. Smart Page Computer Science Book-4 5

Points to Know • Computer word is derived from a Latin word ‘Computare’ which means to calculate. • Computer is an electronic data processing device. • Input devices receive, processing device calculates and output device produces information outside. • Computer is a reliable machine due to the following characteristics: • High speed • Accurate • Large storage capacity • Never forgets • Diligent • Versatile Terms to Know Electronic : Components such as microchips and transistors that control and direct electric currents Process : Series of actions or steps taken in order to get a particu- lar result Input : Supplying data into the computer Output : Final result produced by computer Instruction : Direction or order to do something Diligent : Constant in effort to complete a task Versatile : Able to do many different functions Storage : Storing something for future use Page Knowing Computer 6

Worksheet Objective Questions computare output fraction high storage input on and Off electronic 1. Fill in the blanks with the suitable words: a. Computer word is derived from the Latin word ................................ b. Computer is an .................................... data processing device. c. A computer has .................... storage capacity. d. Computer can solve a sum in the ............................. of a second. e. Computer works in the basis of electric pulses .................................... f. Computer stores data in the .............................. device. g. Computer accepts data and instructions from the ................................ device. h. Computer produces the output result through ............................ device. 2. State whether the following statements are true(T) or false (F) a. Computer is a magical device. b. Computer can not forget. c. Computer can perform different types of task. d. Computer feels tired and bored after doing certain work. Smart Page Computer Science Book-4 7

e. Data can be erased by itself from storage device, f. Computer is an accurate machine. g. Computer can process millions of instructions persecond. h. Computer gives the effort constantly to complete a task. Descriptive Questions 1. Answer the following questions: a. What is computer ? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... b. Why do you use computer ? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... c. What is the basic working principle of computer ? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... Page Knowing Computer 8

..................................................................................................................................... ..................................................................................................................................... d. Why is computer called versatile machine ? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... e. Where are computers used ? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Case Study and Application-based Questions 1. Sanduk Lama said, \"computer performs the task repeatedly without losing its speed and accuracy for a long time.\" Which characteristic is being focused by Sanduk? Ans: ............................................................................................................................ ..................................................................................................................................... 2. Bhurka Gauro said, \"computer can be used for all sorts of tasks. It can also do many of the same tasks in different ways.\" Which feature is being focused by Bhurka? Ans: ............................................................................................................................ ..................................................................................................................................... Smart Page Computer Science Book-4 9

3. Sadhu Ram Chaudhary is working in a school. He wants to introduce computers in the School. But School's principal is not interested to introduce computer. How would he convince the principal in this case? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Activity 1. Manage your class in two groups and organize a chart paper presentation on the following topics: a. Application fields of Computer b. Characteristics of computer 2. Organise a speech competition in the class on the topic 'Computer is diligent and versatile machine'. Project Work 1. Write an article for your school's news bulletin on the topic 'Computer makes our work easier'. Page Knowing Computer 10

CHAPTER 2 Evolution of Computer LEARN and ACT Zigme : Mingma, what do you think about today’s computers? Are today’s computers same as they were in the past? Mingma : No, they aren't same. They are totally different from the earlier days. Jigme : Please, Mingma, can you tell me about the evolution of computer? Mingma : I must tell you. Let's learn about some early computing machines. ABACUS Abacus was the first calculating device. It was invented in the sixteenth century (in 3000 BC.) in China. Simple calculations, like addition or subtraction, could be performed using the Abacus. The three most popular abacus were Chinese, Japanese, and Russian. Smart Page Computer Science Book-4 11

NAPIER’S BONES Napier’s Bones was invented by John Napier in 1617. It could perform addition, subtraction, multiplication and division. This device was made up of set of rectangular rods. The improved form of Napier’s Bones were used for performing division and square roots. The rods were made up of craved bones and that is why the device was known as Napier’s Bones. PASCALINE Blaise Pascal was a ‘French mathematician’. He invented the first calculator in 1642 called ‘Pascaline’. It consisted of a rectangular box with eight movable wheels. The Pascalline could only add and subtract. DIFFERENCE ENGINE Charles Babbage was a mathematician at Cambridge University. In the 18th century, he invented the first mechanical computer called the ‘Difference Engine’. This machine could calculate mathematical table mechanically. Page Evolution of Computer 12

ANALYTICAL ENGINE Charles Babbage also invented the first general purpose computer called ‘Analytical Engine’. It was proposed in 1837 AD. The Analytical Engine had the same basic principles as the modern computer as INPUT-OUTPUT -MEMORY. So, Charles Babbage is known as ‘Father of computer’. CLASSIFICATION OF COMPUTER TECHNOLOGY Computer technology is classified into following six types, based on their historical advancement of technology and electronic components used. Zeroth Generation Computer (1642-1946) The zeroth generation of computer was marked by the invention of mainly mechanical computer. Example of zeroth generation computers are ‘Pascline’, ‘Analytical Engine’, etc. First Generation Computer (1946-1959) The first generation of computer was marked by the use of vacuum tubes or valves as basic electronic component. • They were very big in size. • Long electric wires were used. • A lot of vacuum tubes were used • These computers generated too much heat. • Machine level programming language was used Mark I & ENIAC (Electronic Numerical Integrator Smart Page Computer Science Book-4 13

And Computer) were the example of first generation computers. Second Generation Computer(1959-1965) The second generation of computer was marked by the use of transistors in place of vacuum tubes. • These computers were smaller in size • Produced less heat • Computing speed had increased • Assembly language was used for programming MARK-III, PDP (Programmed Data Processor) -1, IBM(International Business Machine) 1401, IBM 650 were examples of second genera- tion computer. Third Generation Computer(1965-1971) The third generation of computer was marked by the use of integrated Circuit (IC) in place of transistors. • They were smaller in size and cheaper than second generation computer. • They were able to reduce computational time and low maintenance cost. • New input and output devices like scanner, magnetic ink character reader, etc. came into the market dur- ing this time. • High level languages were developed. • They were used as operating system • Capacity of main memories were greatly enlarged PDP-8, IBM 360 and IBM 370 were example of third generation of computers. Page Evolution of Computer 14

Fourth Generation Computer (1971-1980) The fourth generation of computer was marked by the use of Very Large Scale Integrated (VLSI) circuits in place of ICs. • These computers had microprocessor-based system. • They were the cheapest among all the com- puter generation. • They had large memory and high functional speed. • Many more high level languages were used such as PASCAL and C language. • Some of the fourth generation computers were IBM 4341, DEC 10, IBM PC, and APPLE- III. Fifth Generation Computer (1980 - onwards) The fifth generation of computers are still under research. These computers will use Ultra Large Scale Integrated (ULSI) circuits in the place of VLSI circuit. They will have artificial intelligence. The main purpose of fifth generation of computer is to create computers that can think, behave and react in the same way as we humans do. For example, Robots have a few features of fifth generation computing. Artificial Intelligence Smart Page Computer Science Book-4 15

Points to Know • Abacus was the first calculating device. It was invented in the sixteenth century (in 3000 BC.) • Napier’s Bones could perform addition, subtraction, multiplication and division. • Blaise Pascal invented a first calculator in 1642 called ‘Pascaline’. • Charles Babbage invented the first mechanical computer called the ‘Difference Engine’. • The Analytical Engine had the same basic principles as the modern computer as INPUT- OUTPUT – MEMORY. • Computer technology is classified into six types, based on their historical advance- ment of technology. • The six phase of computing technology based on : • Zero generation - mechanical technology • First generation - Vacuum tubes • Second generation - Transistors • Third generation - IC • Fourth generation - VLSI • Fifth generation - ULS Terms to Know Vacuum Tubes : A glass tube that has its gas removed, creating a vacuum. Transistor : A semiconductor device used to amplify or switch electronic signals and electrical power. AI : the simulation of human intelligence processes by machines IC : A semiconductor chip on which thousands or millions of tiny resistors, capacitors, and transistors are fabricated Mechanical : Operated by use of machinery or tools Page Evolution of Computer 16

Worksheet Objective Questions vacuum tubes rods fifth mathematician mechanical eight calculator Analytical Engine 1. Fill in the blanks: a. Napier's Bones were made up of a set of rectangular .............................. b. Pascaline consists of a rectangular box with ..................................... movable wheels. c. Charles Babbage invented the first ................................... computer called Difference Engine. d. First general purpose computer was called .......................................... e. The first generation of computer was marked the use of .......................... f. The ................................. generation of computers are still under re- search. g. Blaise Pascal invented the first .............................. called Pascaline. h. Charles Babbage was ................................. at Cambridge University. 2. State whether the following statements are true(T) or false (F) a. Robots have few features of fifth generation of computing. b. Pascal and C language were used in fourth generation. c. Fourth generation is based on IC . Smart Page Computer Science Book-4 17

d. High level programming language was used in the second generation computer. e. Machine level programming language was used in first generation computer. f. Analytical Engine is an example of zeroth generation of computer. g. Charles Babbage is called the father of computer. h. Blaise Pascal was a French Mathematician. i. Abacus was the first calculating device. j. The Second generation computing was based on transistors. 3. Write the full forms of following: a. ULSI ...................................................................................................... b. VLSI ...................................................................................................... c. IC .......................................................................................................... d. PDP ....................................................................................................... e. IBM ........................................................................................................ f. ENIAC ................................................................................................... Page Evolution of Computer 18

4. Write the name of the inventor and date of invention of these devices: Device Name of Inventor Date of Invention Abacus Napier's Bone Pascaline Difference Engine Analytical Engine 5. Match the followings: a. First general purpose computer Abacus b. First mechanical computer Difference Engine c. First calculator Napier's Bone d. First calculator Analytical Engine Pascaline Descriptive Questions 1. Answer the following questions: a. What is the contribution of John Napier? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Smart Page Computer Science Book-4 19

b. Why is Charles Babbage called father of computer? Ans: ............................................................................................................................. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... c. How is the second generation computer more efficient than the first generation computer? Ans: ............................................................................................................................. ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... d. Write any three features of the third generation computer. Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... e. What is Abacus? Ans: ............................................................................................................................. ..................................................................................................................................... ..................................................................................................................................... Page Evolution of Computer 20

..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... f. How is the fourth generation computer is more efficient than the third generation computer ? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... Case Study and Application-based Questions 1. Sukadev Thakur told us about the computers which behave as we human being. a. Which generation of computer is he talking about? Ans: ............................................................................................................................ b. Which technology is used for this activity? Ans: ............................................................................................................................ 2. Shankar Dev presented his presentation on the topic 'Programming language' used in different time period of computing technology development. a. Name the different types of programming languages that he discussed. Ans: ............................................................................................................................ b. Write the name of time period when those languages were used? Ans: ............................................................................................................................ Smart Page Computer Science Book-4 21

3. Shikha Mandal has been assigned a task to make a presentation on the chart paper, about the 'Generation of the computer.' a. What would Shikha prepare on the chart paper? Prepare as Shikha Mandal did and paste a photograph. Activity 1. Manage your class in three groups and organize a group discussion in the following topics: a. Evolution of computer b. Generation of computer 2. Present the chart paper in the class that you had prepared as Shikha Mandal on the basis of question no. 3 of analytical case study. Page Evolution of Computer 22

CHAPTER 3 Computer Devices LEARN and ACT Jigme : Hello Mingma! I have many body organs and each organ has a special function. I receive input from sense organs like eyes, ear, tongue, skin and nose. But it is confusing, what about computer? Mingma : Computer also has different parts and each part has special function similar to your sense organs, computer has also input devices like Keyboard, Mouse, etc. Jigme : I have got brain to receive instructions from sense organs to do work. It thinks, store and remembers to do any type of task, but what about the computer, Mingma? Mingma : Computer has a device similar to your brain called CPU. It receives the instructions from input, processes and remembers to perform the task. It has memory to store information. Jigme : I have got mouth, hands, and legs to give the information out by speaking, writing and running, what about the computer? Mingma : Computer gives the information out with the help of output devices like monitor, printer, etc. Smart Page Computer Science Book-4 23

INTRODUCTION Computer is an electronic data processing machine which accepts data and instructions as input, processes them and gives the results as output. The operations that are performed by a computer are: INPUT-PROCESS-OUTPUT. INPUT DEVICES Jigme : When you want to talk to a fellow human being, you can easily talk through your mouth in your language. Your friend too will hear you talking. But what to do if you want to talk to a computer? Mingma : The only way to talk to a computer is through an input device. The input devices are most important part to operate the computer. A large variety of input devices are available for entering data and instructions into a computer. The most commonly used input devices are called mouse and keyboard. Basically there are two types of input devices: 1. Basic Input Devices and 2. Special Input Devices BASIC INPUT DEVICES The input devices which are essential to operate today’s computer are called ‘Basic Input Devices’. These devices are always required for basic input operations. Basically, keyboard and mouse are basic input devices which are most essential for today’s computer. Let's discus about them. Keyboard Keyboard is a basic input device of the computer that is used to enter Page Computer Devices 24

data and instructions directly into the computer. It has keys similar to the type writer. The keys have letters, numbers and symbols written on them. On pressing keys, the characters get typed. Mouse Optical A mouse is another basic input device. It is used to Mechanical run a program, pull down a menu and select the items on Laser screen. So, it is also called pointing device. It is moved by hand around a flat surface and the pointer on the screen follows the motion of the mouse. A mouse has two or three buttons on the top. Buttons on the mouse can be clicked or double clicked to perform a task. Mouse are three types: i) Mechanical Mouse ii) Optical Mouse iii)Laser Mouse Special Input Devices Jigme : Hey Mingma! When I play game on the computer, I find difficulty in using ‘Basic Input Device’. Mingma : Don’t worry! For playing games Page and other special input tasks, computer has ‘Special Input 25 Devices’. Smart Computer Science Book-4

Sometimes basic input devices are difficult to use for special purpose such as drawing, playing games, entering printed text and images, recording voice etc. The input devices which are used for special pur- poses are called ‘Special Input Devices’. These special input devices are: Trackball, Light Pen, Joystick, Scanner etc. Joystick Joystick is a special input device also called pointing device. It works like a mouse and is used to move cursor position on the screen of the monitor. It consists of a stick having a spherical ball at both its lower and upper ends. Joystick is mainly used to play computer games. Light Pen Light pen is similar to a pen. It is also a pointing device. It is used to select menu item and draw pictures directly on the screen of the monitor. Track Ball Track ball looks like a mouse. But its roller is on the top with selection buttons on the side. Track ball is also a pointing device. It works like a mouse. Specially, it is used in Laptop computer. PROCESSING DEVICE Jigme : I am controlled by my brain and all the activities are directed by my brain. Mingma : Computer has a part that is called CPU. All the calculations Page Computer Devices 26

and decisions are done in this section. And other parts of computer work as what CPU tells? Jigme : But then, it is not like human being, it can’t work itself. Am I right? Mingma : Yes. It needs a set of instructions to work. CPU (Central Processing Unit) is a brain of the computer where all the calculation and decisions are taken. It also controls other parts of computer to do work. It works as our brain but it is not real brain, it needs the set of instruction to work called ‘program’. Parts of CPU The CPU (Central Processing Unit) has three parts: 1) Arithmetic Logical Unit (ALU), 2) Control Unit(CU) and 3) Memory Unit (MU) Smart Page Computer Science Book-4 27

Arithmetic Logic Unit The ALU (Arithmetic Logic Unit) of the CPU (Central Processing Unit) performs all the arithmetic operations, Is X>Y ?such as addition, subtraction, multiplication, division, etc. ALU also performs the comparisons called logical operations, such as less than, greater than, equal to, and not equal to. Control Unit CU (Control Unit) is a central nerves system of the computer. Each and every function of other parts of computer is controlled by Control Unit. Such as input data through input devices, storing data in memory, sending data for operation to ALU, sending result in output device and memory, etc. So we can say “CU is a traffic police of the computer that controls all the movement of information among the other parts of computer.” COMPUTER MEMORY Jigme : Hey Mingma! We can remember any activities for long time, but can computer also remember? Mingma : Why not! Computer also can remember. It has strong Page Computer Devices 28

memory power. Jigme : We can remember through the brain; how does a computer do it? Mingma : Computer has memory device. It stores all the activities in this device, then it can remember. Let's learn about the Computer memory, Jigme. A computer has a large internal memory. It can store a large amount of data and information, and recall it instantly whenever you need. It holds the data and instructions that the Central Processing Unit (CPU) needs. The basic storing unit of the computer's memory is a group of eight bits, which is called a 'byte'. There are two types of memory. 1) Primary memory and 2 )Secondary memory Primary memory It is the main memory of a RAM ROM computer. It is also present inside the CPU. When you input data from the input device, it is stored in the primary memory. It also stores immediate processing result and holds the program and data currently being used by computer. There are two types of primary memory. 1) RAM (Random Access Memory) and 2) ROM (Read Only Memory) Secondary Memory The secondary memory is a permanent memory of the computer. It is not erased even when you switch off. So, you can store data and information permanently in this memory for future use. This kind Smart Page Computer Science Book-4 29

of memory is also called auxiliary memory. Commonly used secondary memory are: • Hard Disk, • Solid-state drive (SSD) • Floppy Disk, • USB drives • Compact Disk • Cloud storage OUTPUT DEVICE Jigme : We produce voice and speak as we like. How does a computer perform this task? Mingma : Computer also produces the output result through the output device. Jigme : Wow ! What types of output device, Mingma? Mingma : Computer has common three types of output devices: Monitor, Printer and Speaker. The device which is used to produce the output result to the user is called output device. Monitor, printer and speaker are the examples of output devices. Monitor Monitor is the screen where whatever you type can be seen as a display output on it. So, it is also called VDU(Visual Display Unit). The output displayed on monitor is known as ‘Soft copy’ output. It forms Page Computer Devices 30

images from tiny dots, called pixels. The sharpness of the image depends upon the number of pixels. Monitors are available in different sizes. The common size of monitors are 17”, 19”, 21” , etc. Types of monitor Monitors are classified into the following two types on the basis of color of display. • Monochrome Monitor (Displays output in color black and white) and • Color Monitor (Displays output in multi colors) Printer Printer is another popular output device of the computer. It is used to print the information on the paper. There are different types of printers: • Character printer • Line printer • Page Printer Character printer Character printers are the oldest printing devices and are still in use. These printers print one character at a time. ‘Daisy Wheel Printer’ and ‘Dot Matrix Printer’ are example of character printer. Dot matrix printer is noisy. Line Printer The printer which prints one line at a time is called line printer. It is faster than character printer. Especially it is used to print the light Smart Page Computer Science Book-4 31

printing application such as banking token, telephone and electricity bill etc. Thermal Dot Line printer is an example of ‘Line Printer’. Now a days it is very much popular. Page printer Page printer prints one page at a time. It gives high quality of print- ing. It is very fast printer. Laser and Ink Jet are the examples of page printer. Ink Jet Printer Laser Printer Speaker A computer speaker is an output hardware device that connects to a computer to generate and produce sound. The signal used to produce the sound comes from a computer speaker is created by the computer's sound card. Page Computer Devices 32

Points to Know • Computer is an electronic data processing machine which accepts data and instructions as input, processes them and gives the result as output. • The most commonly used input devices are called mouse and keyboard. • Keyboard is a basic input device of the computer used to enter data and instructions directly into the computer. • Mouse is used to run a program, pull down menu and select the items on screen. • The input devices which are used for special purposes are called ‘Special Input Devices’. Such as Trackball, Light Pen, Joystick, Scanner etc. • Joystick is mainly used to play computer games. • Light pen is used to select a displayed menu item and draw pictures directly on the screen of monitor. • Track ball works like a mouse. But its roller is on the top with selection buttons. • CPU (Central Processing Unit) is a brain of the computer, where all the calculation and decisions are taken. • All the calculation and comparison are done in ALU of CPU. • All the other parts of computer’s works are controlled by Control Unit. So, it is called central nervous system. • Computer memory can store a large amount of information and recall it instantly whenever you need. • Input data, immediate processing result and data currently being used by computer are stored in the primary memory. • You can store data and information permanently in secondary memory for future use. • The device which is used to produce the output result is called output device. Monitor, printer, speaker are example of output devices. Smart Page Computer Science Book-4 33

Terms to Know Electronic : Operating with components such as microchips and transistors that control and direct electric currents Instruction : Order to do something Input : Supply something into the computer Process : Actions or steps taken in order to achieve a particular result Output : Something displayed or produced by computer Pixels : The smallest unit of a digital image or graphic Device : An object that has been invented for a particular purpose Program : A set of instructions that a computer follows in order to perform a particular task Worksheet Objective Questions soft-copy joystick secondary mouse brain light pen processing keyboard 1. Fill in the blanks: a. Computer is an electronic data ............................. machine. b. ............................ is an input device, used to type and enter data and instruction. c. ............................... is used to run a program, pull down menu and select items on screen. Page Computer Devices 34

d. ................................. is mainly used to play video games. e. .............................. is used to draw pictures directly on the screen. f. CPU is a ........................... of the computer. g. The output display on monitor is known as ................................. output. h. The ................................ memory is a permanent memory of computer. 2. Write 'T' for true and 'F' for false statements: a. Joystick is an output device. b. Keyboard a typing input device. c. Light pen is a pointing device. d. Track ball is an output device. e. CPU controls other parts of computer. f. Primary memory is the main memory. g. Secondary memory is an auxiliary memory. h. Monitor forms image from tiny dots, called pixels. i. The quality of the image depends upon the number of pixels. j. Mechanical mouse is a new technology. k. Speaker is an output hardware device. l. Laser and Ink jet are examples of line printer Smart Page Computer Science Book-4 35

3. Write the full forms of following: a. CPU ...................................................................................................... b. ALU ...................................................................................................... c. CU ......................................................................................................... Descriptive Questions 1. Answer the following questions: a. What do you mean by input device? Ans: ............................................................................................................................. ...................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... b. Why is CPU called brain of the computer ? Ans: ............................................................................................................................. ...................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... Page Computer Devices 36

c. What is the function of ALU? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... d. What is the function of CU? Why is it called central nervous system? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... e. What is computer memory? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... .................................................................................................................................... Smart Page Computer Science Book-4 37

f. What do you mean by byte? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... g. What is the function of primary memory? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... .................................................................................................................................... h. Why do you use secondary memory? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... .................................................................................................................................... Page Computer Devices 38

i. What do you mean by output device? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... .................................................................................................................................... j. What is printer? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... .................................................................................................................................... k. Why do you connect speaker with computer? Ans: ............................................................................................................................ ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... ..................................................................................................................................... .................................................................................................................................... .................................................................................................................................... Smart Page Computer Science Book-4 39

Case Study and Application-based Questions : 1. Madhukar Rai saw a printing process at the electricity bill office to produce the bill. The printer was very slow and produced loud noise. a. Which printer did Madhukar see? Ans: ............................................................................................................................. ..................................................................................................................................... 2. Look at the following two devices. I) II) a. Write the name of these two devices. Ans: ............................................................................................................................. ..................................................................................................................................... b. Where are these device used ? Ans: ............................................................................................................................. ..................................................................................................................................... 3. Ramananda Yadav plays game in the computer. He feels uneasy to play game with common input device. Which device would you like to suggest Ramanada for playing game easily? Ans: ............................................................................................................................. ..................................................................................................................................... 4. Ram Prit Paswan is an engineer. He has to make drawing on the computer. Which device is suitable for him ? Ans: ............................................................................................................................. ..................................................................................................................................... Page Computer Devices 40

Activity 1. Manage your class in four groups and organize a group discussion in following topics: a. Input devices b. Processing device c. Output devices d. Memory device 2. Prepare and present a chart paper in the class according to group discussion that you performed in above. Project Work 1. Write an article for your school's news bulletin on the topic 'CPU is as our brain' . Smart Page Computer Science Book-4 41

CHAPTER Microsoft Windows 4 INTRODUCTION Microsoft Windows is one of the most popular operating system, developed by ‘Microsoft Company’ in USA. When you switch on the computer, the windows operating system gets loaded into the computer memory automatically. While loading, the picture of Windows flag will appear on the screen. Windows operating system software are available in different versions such as Windows 95, Windows 98, Windows 2000, and Windows XP, Windows 7, Windows 10. Microsoft released Windows 1.0 in 1985, as the first version of Windows line. Desktop When you switch on your computer, after few seconds the windows flag appears, then you will see the following screen on the monitor with the many small pictures. The displayed screen is called desktop and small pictures are called icons. Page Microsoft Windows 42

Icons The small pictures shown on the desktop are known as ‘Icons’. Each icon represent a program or software, file or folder. You can open icons by double clicking on them using the left mouse button, which is also called executing the program. The most common icons of the desktop are: 1. This Computer, 2. Recycle Bin, 3. Control Panel, 4. Network Places and 5. User 's Files Tricks & TIPS You can also open the program from the desktop by clicking the left mousse button once on the icon called select the program and then pressing the ‘Enter’ key. Taskbar The taskbar is a long horizontal bar which is placed at the bottom of the desktop. It contains buttons with icons, which represent the programs that are open on the system. It also contains 'Start' button, search box and time indicator. For example, if the ‘MS-Word’, MS-Excel, PowerPoint programs are opened, the task bar would look as shown below. Start Button Page The ‘Start’ button is located at the left 43 corner of the taskbar. It is used to start any program. It contains ‘Start menu’ along with many options. Clicking on the ‘Start’ button will display a menu called ‘Start menu’. Some of the menu item has symbolic arrow that indicates sub options. Moving the mouse Smart Computer Science Book-4

pointer on the symbolic arrow, sub menu will be displayed. Tricks & TIPS By pressing the windows key from the keyboard, you can open the ‘Start menu’. This PC Whenever you have switched on your computer, ‘This PC’ icon is seen on the desktop. This icon represents the whole computer system. When you double-click on the icon of ‘This PC’, you will get 'This PC' dialog box. You can see storage device drives icons as given in the picture. WINDOW Whenever any icon, program or application is opened, a rectangular frame appears on the screen which is known as a window. Here it is given a window of calculator program. The ‘Calculator’ Window A calculator is a program that helps in performing mathematical calculations. Whenever you click the calculator program, it opens this window. Page Microsoft Windows 44

Components of window The window has the following parts. • Title Bar, • Menu Bar, • Minimize Button, • Maximize button, • Close Button, • Scroll Bar, • Status bar and Title Bar Menu Bar Minimize, Maximize & Close Buttons • Resize Corner Vertical Scroll Bar Horizontal Status bar Resize Corner Scroll Bar Title Bar The Title Bar is located at the top of the window. This bar shows the name of the Program or the window. Let's see the ‘Title Bar’ of ‘Calculator’ where you can see the name of the window 'Calculator'. Menu Bar The Menu Bar is located just below the ‘Title Bar’. This menu has Smart Page Computer Science Book-4 45