Green-Computer-Book-8

i. What is AutoFill? Give its importance.
j. What is cell address? List the different types of cell address.
k. What is Pivot Table? Write the steps to create Pivot Table.

2 . Fill in the blanks:

a. We can delete a worksheet from ....................... menu.

b. ....................... makes the calculations and the use of formula easier
and shorter.

c. ....................... operators are used to perform mathematical operations
or calculations

d. ....................... operators are signs or symbols which are used to
compare two or more than two conditions.

e. ....................... is a graphical representation of data in range.

3. State whether the following statements are TRUE or FALSE:

a. You can insert, delete, move and rename worksheets in a
spreadsheet.

b. The function AVERAGE () is used to calculate the average of the cells.

c. The operator (/) is used for division.

d. The logical operator '<> ' represents less than and greater than.

e. The function NOW () inserts the current system date into your
worksheet.

4. Choose the correct option for the following statements:

a. How many worksheets are available in MS-Excel workbook by
default?

i. One iii. Three

ii. Two iv. Four

GREEN Computer Book-8 101

b. Which of the following functions calculates sum of the cells?

i. Total iii. Average

ii. Sum iv. Percentage

c. Which of the following functions determines the maximum of the
cells?

i. Maximum iii. Min

ii. Max iv. None

d. Which of the operators is used to calculate the product of numbers?

i. Multiply iii. * (Asterisk)

ii. product iv. / (Slash)

e. Which of the operators is used for calculating percentage?

i. Percent iii. Per

ii. % (Percentage. iv. None

5. Label the given figure:

102 GREEN Computer Book-8

Practical: 1

1. Perform the following tasks in MS-Excel.
a. Create the following worksheet:

Sn. Name Post Salary PF Total Net
1. Annap Director 4500
2. Nilgiri Manager 4200
3. Pumori Clerk 3230
4. Everest Peon 2300

b. Calculate PF which is 10% of salary having post director, 15% of
salary having post manager and 5 % of salary for peon. Remove the
grid lines and supply the border for the sheet.

c. Calculate the total salary of every employee in the total columns which
is sum of salary, D.A., P.F. and 20% of salary. Format the column with
two decimal places.

d. Fill the net salary in column name Net Salary and bold them. (Hint
Net salary should be total salary – P.F.

e. Format the column D through H and assign the default currency
symbol.

Practical:2

a. Create the following worksheet:

AB C D EF G

S.N. NAME POST SALARY ALLOWANCE P.F Tax(15%) NET
SALARY

1 Rohan MD 50000 ? ?? ?

2 Ramesh Manager 45000 ? ?? ?

3 Mannu Administrator 40000 ? ?? ?

4 Mukesh Secretary 35000 ? ?? ?

5 Romi Helper 30000 ? ?? ?

Grand Total ? ? ?? ?

b. Remove the grid lines and supply the border for the sheet.

c. Compute Allowance, which is 5 % of salary for post Director and 10%
for others.

GREEN Computer Book-8 103

d. Compute PF 10% of salary for each.

e. Deduct 15% tax from salary after deduction of p.f.

f. Compute Net Sal which is the difference from sum of column D and
E with column F. (Hint: Column D+E-F) and supply default currency
from column D- F.

g. Find Grand Total of each column.

h. Save the file under your symbol no with Password “SECRECT”.

Practical: 3

Create a worksheet to prepare the following report.

S.N Name Maths Science English Nepali Computer Total Grade Remarks

1 Radha 88 78 75 67 98
2 Mohan
3 Arpita 84 77 78 79 98
4 Sneha
5 Roji 78 79 73 66 99
6 Kamal
7 Januka 86 89 75 64 96
8 Prakash
9 Prem 89 98 76 68 97

98 86 79 77 93

96 85 80 75 91

95 87 86 73 89

93 83 88 67 99

a. Find the total marks of students.

b. Find the grade of each student. (Ask about grading system to your
teacher)

c. Insert a column chart from the above worksheet.

Practical: 4

Create a pie chart for the following table:

A. Students of Class Eight

Dist. 1st 2nd 3rd
5
10 15 18

B. Students of Class Eight 2015 2016
2012 2013 2014 50 65
45 50 62

104 GREEN Computer Book-8

Practical: 5

Practical: 6

Complete the following calculation.

Find total price (Cost price * Rate )
Discount 35%
Net cost =total price-discount

GREEN Computer Book-8 105

9 Advance Features of

PowerPoint

Introduction

Microsoft PowerPoint is a presentation application that produces dynamic and
powerful slide shows containing text, graphics, tables and charts. We can use
PowerPoint for formal and informal presentations and meetings, as well as for
presentations on the Internet. You have already studied about PowerPoint in
detail in class 6 and 7. Now we discuss some more features and functions of
PowerPoint.

Formatting Text

Many of your slides will require you to enter text in the placeholder boxes.

1. When typing text PowerPoint will automatically place the text into
bulleted lists to make minor points under major points. PowerPoint will
also automatically text fit the text reducing font size and line spacing to fit
everything into the placeholder boxes.

2. To change the text font, color and size, use commands in the Font group.
3. To change the paragraph formatting such as bullet type, text indentation,

and line spacing use the commands in the Paragraph group.
106 GREEN Computer Book-8

Position text horizontally in a shape or text box

To change the horizontal alignment of a Text Direction
single paragraph or line: To change the
horizontal alignment of all text in a shape
or text box:

1. Click the border of the shape or text
box to select it.

2. On the Home tab, in the Paragraph
group, click the horizontal alignment option that you want.

3. Click in the paragraph or line of text that you want to modify.

4. On the Home tab, in the Paragraph group, click the horizontal alignment
option that you want.

To change the horizontal alignment of all text in a shape or text box:

1. Click the border of the shape or text box to select it.

2. On the Home tab, in the Paragraph group, click the horizontal alignment
option that you want.

Position text at the top, bottom, or middle of a shape or text box

You can specify the vertical alignment of text in a shape or text box.

1. Right-click the border of the shape or text box.

2. On the shortcut menu, click Format Shape, and then click Text Box in the
left pane.

GREEN Computer Book-8 107

3. Under Text layout, select the option that you want in the Vertical alignment
list.

Adding a Design Theme

A theme includes a background design, color scheme, font types, font sizes,
and placeholder positions in one package. Every new presentation starts out
with the default theme, called Office theme, which is a white background and
black text.
However, you can change the theme to a wide variety of options. To find and
apply a theme, click the Design tab on the Ribbon.

Change the Background
Design Tabs >> Background >> Background Styles
• Click on the Format Background button at the bottom.
• The Format Background dialog box will appear.
• You can set the color, solid or gradient, transparency or choose picture/

texture fill.
• Click the Close button to apply changes only to the current slide.
• Click on Apply to All to apply changes to all the slides.

Change the Theme
Design Tabs >> Themes
• Move the cursor over the theme buttons to Preview different themes on

your current slide.
• To choose a theme - Click on any theme button.
• The theme will then be applied to all the slides in your presentation.
• Colors -- Changes the color scheme of the current theme.
• Fonts -- Changes the font of the current theme.
• Effects -- Changes the effects of the current theme.

108 GREEN Computer Book-8

Viewing Slides

Microsoft PowerPoint provides different ways to presentation. You can view
slides on Normal view, Slide Sorter view and Slide Show View. Each of these
views has different look and is used for performing different tasks.

Slide View : To be in Slide view you click on the following button located in
the bottom-left hand corner of any slide: ( ).

The Slide view shows a single slide. In Slide view, you work on one slide at a
time. Here, you can type your slide title and body, add other text to the slide,
draw shapes, add clip art, choose a color scheme, make a graph, etc. In Slide
view, you have access to all the tools on the Tool Palette as well as buttons on
the Toolbar.

Normal View : The Normal view is the default view of Power Point. It is used
for creating and editing slides. The Normal view splits the working screen into
three panes: Outline Pane, Slide pane and Notes pane.

Outline View : To be in Outline view, you click on the following button located
in the bottom-left hand corner of any slide: ( ).

The Outline view shows all the titles and body text in your presentation. In
Outline view, you can move slides around within your presentation and also
edit your text.

Click on the Outline view button ( ), to view your title slide in this view.

Slide Sorter View :To be in Slide Sorter view you click on the following button
located in the bottom-left hand corner of any slide: ( ).

The Slide Sorter view shows you a miniature of each slide in your presentation.
You can drag slides around on the screen to reposition them in this view. You
can also select and copy multiple slides, should you want to use them in other
presentations.

Click on the Slide Sorter view button ( ), to view your title slide in this view.

Notes View: To be in Notes view you click on the following button located in
the bottom-left hand corner of any slide: ( ).

The Notes view lets you create speaker's notes. Each page corresponds to a
slide in your presentation and includes a reduced image of the slide. You can
draw and type in Notes view the way you can in Slide View.

Click on the Notes view button ( ), to view your title slide in this view.

GREEN Computer Book-8 109

You now know all of PowerPoint views. There is one more button located at
the bottom- left hand corner of any slide:( ). This is the Slide Show button.
The Slide Show button runs a slide show starting from the currently selected
slide.
Slide Master
The Slide Master acts as a template for your entire presentation. Altering
anything on the Slide Master will change the formatting of all the slides in
your presentation.

Open the Slide Master
• View Tab >> Presentation Views >> Slide Master.
The Slide Master Tab appears on the left-hand side of Home Tab.
Edit the Slide Master
• Clicking on the Slide Master Tab provides a set of Slide effects for objects

Master Formatting Groups:
i. Edit Master.
ii. Master Layout.
iii. Edit Theme.
iv. Background - set the background for all the slides.
v. Page Setup.
v. Close -- Click on Close button to go back to Normal View.
• Choose the top Slide Master Slide in the left panel.
• You can edit the Background, Bullet styles, Slide Titles, and Title animations

here.

Slide Transitions

Slide transitions provide an animated effect to each slide when moving from
one slide to the next during a slide show. There are a variety of transitions that
can be applied to each or all slides including sounds.

110 GREEN Computer Book-8

1. Click the thumbnail 2. Click the animation tab.
of the first slide.

3. Click the fades smoothly transition.
Note: For the remaining slides, you
can choose other transitions.

4. Click Apply To All.

5. Click the thumbnail
of the third slide.

6. Set the time to20 seconds.

GREEN Computer Book-8 111

15 seconds 20 seconds 25 seconds

7 the follow steps 5 and 6 to set the timing for the remaining slides

Slide Animations

Slide animations create animated effects to text and graphics during a slide
show. There are a variety of animations that can be applied to text or graphics
in multiple ways from a single word to all of the text on a slide.

Starting a Slide Show

The best way to view your slides as a show, whether you are previewing
your documents or presenting to an audience, go to the Slide Show tab on the
Ribbon.

1. Click the Slide
Show tab

2. Click From
Beginning

3. Press the Esc key to stop the slide show

Make presentations portable

1. Click the Office button.
2. When the menu appears, click Publish, then Package for CD.
3. When the Package for CD window appears, type:
4. My Movies in the Name the CD box.
112 GREEN Computer Book-8

The PowerPoint Viewer is included by default in this process.

5. Insert a CD into its drive, then click the button.

The PowerPoint Viewer
allows you to run
presentations on computers
that don't have Microsoft
PowerPoint installed.

Printing Slides

One new feature in PowerPoint 2010 is the File tab. This tab incorporates many
of the features in the 2003 and 2007 versions of PowerPoint but makes them
much more user friendly.

To print your slides, click on the File tab, then the Print command. When you
select the Print command, you will notice all of your printing options including
a preview of your document. Select your Print options and click on the Print
command.

GREEN Computer Book-8 113

PowerPoint provides a variety of Print options such as automatically
previewing your document and selecting specific formats in which your slides
will print.
1, Click The
Office Button

2. Use these settings to
print each slide separately

Print Layout

You are able to select how you would
like your slides to be printed by
selecting the drop down arrow next
to the Fill Page Slides command.
Then, click on the format you would
like your slides to print in. The
different options are:
Full Page Slides – print out with each
slide on a full page .
Handouts - print out with up to nine
slides per page
Notes Page - print out of one slide
per page including any notes you
may have added in the Notes Pane while creating your presentation.
Outline View - print out of your text from all of your slides in an outline format.
114 GREEN Computer Book-8

Insert Shapes

Shapes can be used in PowerPoint as a graphic to enhance the presentation or
to insert text into add visual appeal to a slide.

1. Go to the Insert Tab.

2. Click on the Shapes command.

3. A large selection of shapes will appear in a drop down menu.

4. Double click on the shape you want to insert.

5. The shape will appear on the slide.

6. Move the shape to any area of the slide by clicking on the edge of the shape
and dragging it. Expand or shrink the shape by clicking on the circles
surrounding the shape and drag.

Inserting Pictures

Pictures are another way to
include graphics into a PowerPoint
presentation. Many people like
using this feature to incorporate
pictures from their personal
collection to distinguish their
presentation.

1. Go to the Insert Tab.

2. Click on the Picture command.

GREEN Computer Book-8 115

3. An Insert Picture box will appear.
4. Select the picture to insert using the folders on the left of the Insert Picture

box.
5. Click Open. The picture will appear on the slide.
6. Move the picture to any area of the slide by clicking on the edge of the

picture dragging it. Expand or shrink the picture by clicking on the circles
surrounding the picture and drag.

Using Sound and Video

• From the Insert menu >choose Movies and Sounds.
• You can choose a movie or sound clip from the Clip Gallery or from a file,

or sound from an audio CD.
• To narrate, choose Record Sound.
• You will need a microphone.
• A sound or video icon will appear on the slide, which will play when you

click on it in your slide show.

Inserting WordArt

WordArt can be used to accentuate important words in a presentation such as
the title.
1. Go to the Insert Tab.
2. Click on the WordArt command.
3. A drop down menu of text options will appear
4. Click on the text design you prefer and a text

box will appear on your slide.
5. Click in the text box to modify the text.
6. Move the WordArt to any area of the slide by

clicking on the edge of the text and dragging it.
Expand or shrink the WordArt by clicking on

the circles surrounding the text and drag.

116 GREEN Computer Book-8

Bulleting and Numbering

For adding list in the existing text

• Click on home tab.

• Select the text that you
want to make a list.

• Click the Bullet or Number
from the paragraph group
for new list.

• Place the cursor where you
want to make list in the
document.

• Now, click on the Bullet
and type the text.

Inserting Hyperlinks

Hyperlinks are used to allow a presenter a way to access a website during
the presentation by pressing a
link inserted into the slide.

1 Go to the Insert Tab.

2 Click or highlight the test
you want to become the
hyperlink.

3 Click on the Hyperlink
command.

4 The Insert Hyperlink box
will appear.

5 Click on the Existing File
or Web Page command on the left of the Insert Hyperlink box.

6 Verify the information in the Text to Display box is accurate.

7 Enter the web address in the Address box, then click OK.

8 The hyperlink will appear in the text on your slide by changing the color
of the text to blue and underlined.

9 To use the link you must be viewing the slide show.

GREEN Computer Book-8 117

Creating a Photo Album

A PowerPoint photo album is a presentation that you can create to display
your personal or business photographs using the same fun features as a
PowerPoint presentation.
To create a photo album:
1. Click on the Insert tab.
2. Click on the Photo Album

command.
3. Click on the New Photo

Album option.
4. Click on the File/Disk

command to select pictures
you have saved on your
computer that you want to
incorporate into your Photo
Album. Once you select a picture, it will be listed in the Pictures in album
box.
5. Click the Create command and your photo album slide show will be
created.

To modify your photo album:

1. Click on the Edit Photo Album command.
2. Use the Album Layout group to select the Picture layout, Frame shape and

add a Theme.
3. Once all changes are complete, click on the Update command and the

changes will be applied to your photo album.

118 GREEN Computer Book-8

POINTS TO REMEMBER
1. PowerPoint provides a variety of professionally designed templates

and style galleries to help you create great looking presentations.
2. The Ribbon is located at the top of the application window and displays

Tabs containing groups of commands.
3. A theme includes a background design, color scheme, font types, font

sizes, and placeholder positions in one package.
4. Inserting a Text Box is done in the same manner except when it is

inserted, a curser will appear inside the box so you can enter text.
5. The various boxes with the dotted borders are called placeholders.
6. Slide animations create animated effects to text and graphics during a

slide show.
7. Slide transitions provide an animated effect to each slide when moving

from one slide to the next during a slide show.
8. You can view slides on Normal view, Slide Sorter view and Slide Show

View.
9. The Slide Sorter view shows you a miniature of each slide in your

presentation.
10. The Slide Master acts as a template for your entire presentation.
11. Hyperlinks are the links inserted into slides that allows to access a

website during the presentation.

Exercise

1. Answer the following questions:
a. Why do we need presentation software?

b. What is slide transition?

c. Define MS-PowerPoint.

d. What is slide and slide master?

e. What are the different ways of creating a presentation?

f. Write the ways to view slides.

g. Write steps to insert sound and video in a presentation.

h. Define hyperlink. Write steps to insert hyperlink into slide.

GREEN Computer Book-8 119

2. Write short notes:

i. Motion path ii. Slide transition iii. Slide animation

iv. Presentation software v. Place holder

3. Choose the best anser:

a. CTRL+O is used to ............................. presentation.

i. open ii. close iii. save

b. CTRL+S is used to ............................. presentation.

i. open ii. close iii. save

c. MS-PowerPoint is ............................. software.

i. presentation ii. game iii. none

d. Special effects used to introduce a slide are called ..............................

i. animation ii. transition iii. none

e. ALT+O, K is used to change the background ....................... of slide.

i. colour ii. font size iii. Transition

4. State whether the following statement True or false:

a. Power Point is a presentation software.

b. We can add text and graphics only in a presentation.

c. Slide animations create animated effects to text and graphics during
a slide show.

d. Slide transitions provide an animated effect to each slide

e. Hyperlinks are used to allow a presenter a way to access a website
during the presentation by pressing a link inserted into the slide.

f. The Slide Master acts as a template for your entire presentation.

120 GREEN Computer Book-8

Practice1: Working with Animation
1. Open the Season presentation.
2. Select the Seasonal Weather slide.
3. Right-click the snowflake picture and animate it with a Wheel effect.

TIP: In the Custom Animation pane, click Add Effects, Entrance, then More Effects.
4. Give the presentation a Fade Smoothly transition between slides.
5. Make all slides advance automatically after 4 seconds.
6. Save, preview, then close the presentation.

Practice: 2
1. Prepare presentation about history of computer including pictures.
2. Prepare presentation about types of computer.
3. Prepare presentation about student quality circle.
4. Prepare presentation about impact of computer on society.
5. Prepare an attractive presentation about the Earthquake 2072.

GREEN Computer Book-8 121

10 Concept of ICT

Introduction

Information and Electronic Vehicle
communication technology data tracking

interchange Routing

(ICT) is an umbrella

term that includes any Supplier ICT Delivery
communication device or management scheduling

application; It includes: Freight Information and Radio
radio, television, cellular auditing Communications frequency
phones, computer and
Technology

network, hardware and

software, satellite systems Address Bar
and so on; It also includes systems coding
the various services and
Inventory
management

applications associated

with them, such as videoconferencing and distance learning. ICTs are often

spoken of in a particular context, such as ICTs in education, health care, or

libraries.

Evolution of Communication

Communication has improved and evolved to facilitate our daily activities.
In the 21st century, everything related to communication utilizes technology
to ‘send out’ or disseminate information to a wider audience. Information
can be ‘sent out’ in many ways. Information and communication are essential
to human society. The inventions of cellular phones, television and other
electronic devices are important in enhancing communication.

Fig. : Evolution and communication device
122 GREEN Computer Book-8

What is ICT?

ICT is the technology required for information processing, in particular, the
use of electronic computers, communication devices and software applications
to convert, store, protect, process, transmit and retrieve information from
anywhere, anytime.

Fig. : Relationship among information, communication and technology

These new ICTs can be grouped into three categories:
Information: Information
refers to the knowledge
obtained from reading,
investigation, study
or research. We need
information to make
decisions and to predict
the future. For example,
scientists can detect the
information of a tsunami
using the latest technology
and warn the public to avoid
disasters in the affected areas. Information is knowledge that helps us to
fulfill our daily tasks. For example, forecasting the stock exchange market.
Communications: Communication is an act of transmitting messages. It is a
process whereby information is exchanged between individuals using symbols,
signs or verbal interactions. Previously, people communicated through signs or
symbols, performing drama and poetry. With the advent of technology, these
‘older’ forms of communication are less utilized as compared to the use of the
Internet, e-mail or video conferencing. Communication is important in order
to gain knowledge. With knowledge, we are more confident in expressing our
thoughts and ideas.

GREEN Computer Book-8 123

What is Telecommunication?

Telecommunication is a
communication at a distance via a
collection of information sharing
systems like telephony, telegraphy
and television that all tied together. It
includes the public switch telephone
(PSTN), radio and television
networks and worldwide network.

Technologie: Technology is the use of scientific knowledge, experience and
resources to create processes and products that fulfill human needs. Technology
is vital in communication. Telephone and fax machines are the devices used
in extending communication. It is used to broadcast information such as news
or weather reports effectively. Radio, television, satellites and the World Wide
Web (www) are powerful tools that can be used.

124 GREEN Computer Book-8

The Impact of ICT on Society

Positive Impact of ICT
• Faster communication speed
• Lower communication cost
• Reliable mode of communication
• Effective sharing of information
• Paperless environment
• Borderless communication
• Globalization

Negative Impact of ICT
• Social and cultural problem
• Health problem
• Lack of privacy
• Pornography
• Hacking

Usage of ICT in Daily Life

• Education • Banking • Industry
• Healthcare
• Business • E-commerce • Science and research

• E-Government • Transporation

POINTS TO REMEMBER

1. Information and communication are essential to human society.

2. ICT (information and communications technology - or technologies) is
an umbrella term that includes any communication device or application

3. Information refers to the knowledge obtained from reading,
investigation, study or research.

4. Communication is an act of transmitting messages.

5. Technology is the use of scientific knowledge, experience and resources
to create processes and products that fulfill human needs.

6. There are positive and negative impact of ICT on the society.

7. Telecommunication is a communication at a distance via a collection of
information sharing system like telephony, telegraphy and television
all tied together.

GREEN Computer Book-8 125

Exercise

1. Answer the following questions:
a. What is ICT?
b. Write about the evolution of ICT.
c. List out any five application areas of ICT.
d. What do you mean by communication?
e. What are the positive impacts of ICT in our society?
f. List out some negative impacts of ICT in our society.
g. What is telecommunication?
h. How does technology support in communication?

2. Fill in the blanks:
a. …………. is the use of scientific knowledge, experience and resources
to create processes and products that fulfill human needs.
b. ………………. refers to the knowledge obtained from reading,
investigation, study or research.
c. …………….is an act of transmitting messages.
d. …………… and …………….. are essential to the human society.
e. PSTN stands for ………………………

3. Explain the evolution of communication with reference to the given
picture.

4. Write technical term for the following statement.
a. It is an act of transmitting messages from one to another.
b. The knowledge obtained from reading, investigation, study or
research.
c. It is the use of scientific knowledge, experience and resource to create
processes and products that fulfill human need.

126 GREEN Computer Book-8

11 Cyber Law and Ethics

Introduction

Cyber law is the part of the overall legal system that deals with the Internet,
cyberspace, and their respective legal issues. Cyber law covers a fairly broad
area, around several subtopics including freedom of expression, access to
and usage of the Internet, and online privacy. Generically, cyber law has been
referred to as the Law of the Internet. Cyber law includes the following legal
issues:
• Electronic and digital signature act
• Cyber crime act
• Intellectual property act
• Data protection and piracy act
• Telecommunication act policy

In Europeon countries, cyber
laws and computer ethics
have been introduced since
1970 but in Nepal, cyber
law was introduced on 30th
Bhadra, 2061B.S.

Cyberspace can be defined as a complex environment that involves interactions
between people, software, and services. It is maintained by the worldwide
distribution of information and communication technology devices and
networks.

Cyber ethics/ Computer Ethics

A guideline is needed to stop the current technology products from being
exploited. For example, replicating original CDs and selling them as pirated
software, this unethical behaviour can be controlled by the code of conducts.

GREEN Computer Book-8 127

Unethical refers to any code of conducts that are not conforming to the
approved standards of social or professional behaviour. Computer ethics is a
system of moral standards or values used as a guideline for computer users.

The United States Institute of Computer Ethics has come out with the Ten
Commandments of Computer Ethics. These principles consider the effective
code of conducts for the proper use of information technology. The ten
commandments of computer ethics are :

1. You shall not use a computer to harm other people.

2. You shall not interfere with other people's computer work.

3. You shall not snoop around in other people's computer files.

4. You shall not use a computer to steal.

5. You shall not use a computer to bear false witness.

6. You shall not copy or use proprietary software for which you have not paid.

7. You shall not use other people's computer resources without authorization
or proper compensation.

8. You shall not appropriate other people's intellectual output.

9. You shall think about the social consequences of the program you are
writing or the system you are designing.

10. You shall always use a computer in ways that ensure consideration and
respect for your fellow humans.

Cyber Crime

Alternatively referred to as cyber crime,
e-crime, electronic crime, or hi-tech crime,
computer crime is an act performed
by a knowledgeable computer user,
sometimes referred to as a hacker that
illegally browses or steals a company's or
individual's private information. In some
cases, this person or group of individuals
may be malicious and destroys or otherwise corrupts the computer or data
files.

128 GREEN Computer Book-8

Below is a listing of the different types of computer crimes today.
• Child pornography - Making or distributing child pornography.
• Cyber terrorism - Hacking, threats, and blackmailing towards a business

or person.
• Cyber bully or Cyber stalking - Harassing others online.
• Creating Malware - Writing, creating, or distributing malware (e.g. viruses

and spyware.)
• Espionage - Spying on a person or business.
• Fraud - Manipulating data, e.g. changing banking records to transfer

money to an account.
• Harvesting - Collect account or other account related information on other

people.
• Identity theft - Pretending to be someone you are not.
• Intellectual property theft - Stealing another persons or companies

intellectual property.
• Phishing - Deceiving individuals to gain private or personal information

about that person.
• Salami slicing - Stealing tiny amounts of money from each transaction.
• Scam - Tricking people into believing something that is not true.
• Spamming - Distributed unsolicited e-mails to dozens or hundreds of

different addresses.
• Spoofing - Deceiving a system into thinking you are someone you really

are not.
• Unauthorized access - Gaining access to systems you have no permission

to access.
• Wiretapping - Connecting a device to a phone line to listen to conversations.

GREEN Computer Book-8 129

POINTS TO REMEMBER
1. Cyber law is the part of the overall legal system that deals with the

Internet, cyberspace, and their respective legal issues.
2. Generically, cyber law has been referred to as the Law of the Internet.
3. Cyberspace can be defined as an complex environment that involves

interactions between people, software, and services.
4. Cyber ethics guideline is needed to stop the current technology products

from being exploited
5. Unethical refers to any code of conducts that are not conforming to

approved standards of social or professional behaviour.
6. Cyber crime alternatively referred to as e-crime, electronic crime, or hi-

tech crime, computer crime.

Exercise

1. Answer the following questions:

a. What is cyber law? List out the legal issues of cyber law.

b. Define cyberspace.

c. Write any three important points of cyber ethics.

d. What are the ten commandments of computer ethics?

e. Define cyber crime.

f. List out the different types of computer/cyber crimes.

2. State whether the following statements “True” or “False”.

a. Computer crime is an ethical issue.

b. Cyber crime is known as e-crime.

c. Stealing tiny amounts of money from each transaction is not a cyber
crime.

130 GREEN Computer Book-8

d. Cyber law is the part of the overall legal system that deals with the
Internet, cyberspace, and their respective legal issues.

e. Hackers are legal persons who can browse a company's or individual's
private information.

3. Match the following: Hacking, threats, and blackmailing
Harvesting towards a business or person.
Scam
Cyber terrorism Stealing another persons' or
Wiretapping companies' intellectual property
Spamming
Salami slicing Stealing tiny amounts of money from
Intellectual property theft each transaction.

Distributed unsolicited e-mail to dozens
or hundreds of different addresses.

Tricking people into believing
something that is not true.

Collect account or other account related
information on other people.

Connecting a device to a phone line to
listen to conversations.

GREEN Computer Book-8 131

12 Computer Virus

Introduction

Generally, virus means infection that changes the behaviour of the system.
The nature of a computer virus is very similar to the virus that affects human
beings, so it is called a virus. It diminishes the overall activities of the computer.
A computer virus is a parasitic program written intentionally to enter a
computer without the user’s permission or knowledge. The word parasitic
means replicating itself.
A computer virus is a high threat to a computer. It is like other softwares but
it replicates the files which hang up your computer. It automatically hides in
the system files.

Types of Computer Virus

1. Boot sector virus: Boot sectors exist on storage media, such as hard drives,
floppies, or occasionally CDs and DVDs. During the booting process,
the boot sector program is automatically located by the hardware and
is then loaded. After this, the boot sector loads the remaining portion of
the operating system into the memory. It is impossible for a computer to
load the OS without a boot sector. A boot sector virus usually infects the
computer by altering the boot sector program

132 GREEN Computer Book-8

2. Application or File Infected virus: A file-infecting virus is one of the
most common types of virus. Typically, it infects files with .exe or .com
extensions. When the infected file is accessed or used, the virus may
overwrite code or insert infected code into an executable file. Application
or file infected virus are divided into two categories:

a. Multipartite Virus: These viruses are having multiple features that
can infect both application programs and boot sectors.

b. Macro Virus: A macro virus is a virus that is written in a macro
language, a language built into a software application such as a word
processor. Macro Virus becomes active when an infected document
is opened, and the program opening the document has its macro
capabilities turned on.

c. Stealth Virus: It is the most destructive virus. It does not give
information about its presence. It infects program files and boot
record. This type of virus is very difficult to detect by the operating
system and anti-virus.

3. System Infector Virus: System infector virus is a destructive virus which
infects/ destroys/ corrupts the system files of operation system such as
IO. SYS, COMMAND.COM, MSDOS.SYS, etc. These viruses enter to the
system as a device driver and get loaded into memory.

4. Message Carrying Virus: These viruses display interesting messages,
pictures and dialogs which interrupt the user’s work. These viruses do not
infect the program and system.

Modes of transmission

Viruses are transmitted from one computer to another through different media.
Some of the media are:

• Via email.

• Via downloaded files from Internet.

• Via an exchange of data from other computers.

• Through physical media.

• Through local area network.

GREEN Computer Book-8 133

Symptoms of Computer Virus

Virus acts as a parasite to the system file so it affects the system of the computer.
Some of the common effects of virus are:
• Computer gets extremely slow.
• Runs unnecessary files automatically.
• Mismatches the files.
• Captures the RAM memory.
• Changes the mouse cursor automatically.
• Changes the background automatically.
• Leads to malfunctioning of the system.

How to Protect from Computer Virus

Generally, we use anti-virus programs to remove viruses which are already in
our computer system and also to prevent them from entering into the system.
But, new viruses are being introduced all the time, and our AVG software must
be able to constantly update itself automatically (generally via the Internet).
Some of the measures that help to prevent computer system from being
infected by computer viruses are listed below:
• Don't open email attachments unless you are sure it is safe.
• You should use only legal software in order to prevent your system from

virus.
• Buy software only from proven source.
• Do not use external pen drive and other external drives, without scanning

it.
• Change your password frequently.
• Prevent access to unauthorized users.
• Run Regularly Scheduled Scans with Your Anti-Virus Software.

134 GREEN Computer Book-8

Antivirus

Computer antivirus refers to a software program that can protect your computer
from unwanted viruses and remove any that penetrate your computer's
defenses. Antivirus software is a computer program that detects, prevents, and
takes action to disarm or remove malicious software programs, such as viruses
and worms. It is an important means of keeping your computer functional
and protecting the data you have stored on the computer. A properly updated
antivirus program can save your time and money.

Antivirus software completes three specific tasks.
• The first is prevention,

blocking harmful
software from entering
your computer.
• The second is quarantine
or removal or the
complete destruction of
harmful files.
• The third is repair; the
software can repair
damaged sections of
your computer.
Some of the popular Anti-virus software programs are Kaspersky, Symantec,
NOD 32, Avira, AVG etc.

GREEN Computer Book-8 135

POINTS TO REMEMBER
1. Computer virus is harmful software which infects the computer system.
2. Boot sectors exist on storage media, such as hard drives, floppies, or

occasionally CDs and DVDs.
3. Typically file infecting virus infects files with .exe or .com extensions.
4. A computer virus spreads through physical media, Internet, etc.
5. Anti-virus programs are used to remove viruses.
6. A program or software that detects and removes the computer virus

from an infected file, program or memory is called antivirus.
7. System infector virus is destructive virus which infects/ destroys/

corrupts the system files of operation system.
8. Change your password to protect computer from viruses.
9. Stealth virus is most destructive virus which does not give information

about its presence.
10. Multipartite viruses are having multiple features that can infect both

application program and boot sector.

Exercise

A. Answer the following questions:

a. Define computer virus.

b. Name the types of computer virus.

c. What is system infector virus?

d. List out the modes of transmission of virus.

e. List out the preventive measures against computer virus.

f. What is an antivirus? How does it work?

g. What is stealth virus?

h. What is macro virus?

i. How do computer viruses spread from one computer to another?

136 GREEN Computer Book-8

2. Fill in the blanks:
a. Virus is an unwanted...............................
b. Virus spreads through..............................media.
c. ..............................is the software against the virus.
d. ..............................and .............................. are the types of virus.
e. NOD32 is an example of...............................
f. File infecting virus, infects files with ……………..extensions.
g. ……………… viruses display interesting messages pictures and
dialogues which interrupt the user’s work.

3. State whether these statements are 'True' or 'False':
a. Computer virus is a parasitic program.
b. Antivirus is used to remove the viruses from computer.
c. To prevent the computer from virus infection, we must use pirated
software.
d. NOD32 is an example of antivirus.
e. Virus cannot transmit through email.

4. Technical Terms:
a. The virus that does not infect the computer programs and does not
damage data and information but displays interesting messages,
pictures, dialogues, etc. which may entertain the computer user.
b. A program or software that detects and removes the computer virus
from an infected file, program or memory addresses.
c. A virus that is written a macro language.
d. The viruses are having multiple features that can infect both
application programs and boot sectors.

GREEN Computer Book-8 137

13 Data Communication

and Computer Network

Introduction

Data in a computer is transmitted to another computer located across
continents almost instantly using telephones, microwaves or radio links. The
long distance communication links between a computer and a remote terminal
was set up around 1965. Now networking has become a very important part
of computing activity.

Computer Network

A computer network consists of a
collection of computers, printers
and other equipment that are
connected together so that they can
communicate with each other.

A large number of computers are
interconnected by copper wire, fiber
optic cable, microwave and infrared
or through satellite. "A system
consisting of connected nodes made
to share data, hardware and software is called a Computer Network."

Some Important Reasons for Networking

Sharing of resources:
The primary goal of a computer network is to share resources. For example,
several PCs can be connected to a single expensive line printer, scanner, etc.

138 GREEN Computer Book-8

Sharing information:
Information on computer can be accessed by other computers in the network.
Repetition of data file on separate PCs can be avoided.
Communication: When several PCs are connected to each other, messages
can be sent and received.

Applications of Network

The following are the areas where computer networks are working.
• Electronic data interchange
• Tele-conferencing
• Cellular telephone
• Cable television
• Financial services, marketing and sales
• Reservation of airlines, trains, theatres and buses
• Computer network can be used in telemedician
• ATM (Automated Teller Machine)
• Internet banking

Benefits of Network

• Effective handling of personal communications.
• Allowing several users to access simultaneously important programs and

data.
• Making it easy for the users to keep all critical data on shared storage

device and safeguard the data.
• Allowing people to share costly equipment.
The computer communication should ensure safe, secure and reliable data
transfer.

Safe : The data received is the same as the data sent.

Secure : The data being transferred cannot be damaged either fully or
accidentally.

Reliable : Both the sender and the receiver know whether the receiver got the
correct data or not.

GREEN Computer Book-8 139

Disadvantage of Computer Network

Security Concerns:
If a computer is on a network, a hacker can get unauthorized access by using
different tools.

Virus and Malware:
If even one computer on a network gets affected by a virus, there is a possible
threat to the other systems getting affected too.

Lack of strength:
If the main file server of a computer network breaks down, the entire system
becomes useless.

Needs An Efficient Handler:
The technical skills and know-how required to operate and administer a
computer network is very high. Any user with just the basic skills cannot do
this job.

Lack of Independence:
Since most networks have a centralized server and dependent clients, the client
users lack any freedom whatsoever.

Components of Computer Network

• Server
• Workstation
• Network Interface Card
• Communication Media
• Network Connecting Device
• Network Operating System

Server:
A Server is the main computer of a network having high storage capacity,
high speed processor and high RAM. The existing resources on a network
are managed by the server. It provides access and directions to the clients or

140 GREEN Computer Book-8

workstations for getting the required resources. Servers centralize the control
of resources and reduce the difficulties of administrating computers on a
network. Servers should be installed with Server Network Operating System.

Workstation:
Workstation is the computer on network that uses the resources provided by
the server computer or other computers. It is the computer which is used by
client in order to perform application tasks. It is also known as client computer.
It is controlled by server on the network. Client or Workstation should be
installed with workstation operating system like: windows NT, windows 2007
etc, so that they meet the standards for communicating with Server and other
existing workstations.

Network Interface Card (NIC):
NIC is an interface that connects the workstations to a server computer enabling
them to communicate with each other. One end of the cable is connected to
NIC of a workstation and the other end to a hub. NIC used to be housed on top
of motherboard separately. Nowadays, it comes built-in with the motherboard
in desktops and portables.

Communication Media:
They are the path wires or wireless media through which data get transmitted.
There are different types of media used in computer network. They are:

1. Bounded Transmission Media:
They are also called Guided or Wired Media as the transmission of electronic
signals are guided through wires. Different types of Bound Transmission
Media are:
• Twisted Pair Cable: There are two types of twisted pair cables:
i. Unshielded Twisted Pair (UTP)
ii. Shielded Twisted Pair (STP)
• Coaxial Cable
• Fiber Optic Cable

GREEN Computer Book-8 141

2. Unbound Transmission Media:

Unbounded Transmission Media are the transmission media where wires or
cables are not used. They are Wireless or Unguided Media. The electronic
signals are transmitted on air in the form of electromagnetic wave.

Different types of Unbound Transmission Media are:

a. Radio waves b. Microwaves

c. Infrared d. Communication Satellite

Network Connecting Devices:
Connectivity wires are not only sufficient to make communication on network.
Network connection devices are the peripheral devices that are required to
connect computers on the network.

Some of the frequently used and important connectivity devices are:
1. Hubs/Switches
2. Repeaters
3. Bridges
4. Routers
5. Gateways
6. MODEM

1. Hubs/Switches

A hub is a simple device that works
as a central point to receive the
signals from all the workstations
and a server computer. They are just
like multiport repeaters. The signal
transmitted from a port is repeated
and copied to all other ports known
as broadcasting. Switches are
similar to that of hubs. They are
used to connect many computers to
form a LAN. Instead of repeating

142 GREEN Computer Book-8

the received signals from a port to all other ports, they examine the header of
the packet and forward it properly to the right port only.

2. Repeaters
Electronic signals get weaker when
they travel a long distance. Repeaters
are the simple devices that amplify
these signals to travel farther. Repeaters
are like the amplifiers and are very
expensive.

3. Bridges
Bridges are the devices that join network of computers with similar topologies.

4. Routers
Routers are highly intelligent devices that connect different types of computer
network.
They are able to choose the best route for sending data from the data highway.
Generally, they are used to connect one LAN to another.

5. Gateways
Gateways connect dissimilar networks. They convert data and repackage it to
meet the requirements of the destination address.

6. MODEM
A MODEM (Modulator Demodulator) is a network connecting device that
enables a computer to transmit digital data over analog telephone lines. A
modem converts digital signal into analog and vice versa. There are two types
of MODEM: internal MODEM and external MODEM.

Types of Computer Networks

The following are the general types of networks used today.

• Local Area Network (LAN)

• Metropolitan Area Network (MAN)

• Wide Area Network (WAN)

GREEN Computer Book-8 143

Local Area Network (LAN)

A local area network, or LAN,
consists of a computer network
at a single site, typically an
individual office building. A
LAN is very useful for sharing
resources, such as data storage
and printers. LANs can be built
with relatively inexpensive
hardware, such as hubs, network
adapters and Ethernet cables.

The smallest LAN may only use
two computers, while larger LANs can contain thousands of computers. A
LAN typically relies mostly on wired connections for increased speed and
security, but wireless connections can also be part of a LAN. High speed and
relatively low cost are the defining characteristics of LANs.

Features of a LAN

• Limited geographic operation.

• High speed data transfer rates.

• Full time connectivity to local services.

• Generally lower in cost than a WAN.

• Cabling is primary transmission medium.

Metropolitan Area Network (MAN)

A metropolitan area network,
or MAN, consists of a computer
network across an entire city, college
campus or small region. A MAN
is larger than a LAN. Depending
on the configuration, this type of
network can cover an area from
several miles. A MAN is often used
to connect several LANs together to
form a bigger network. When this type of network is specifically designed for
a college or campus, it is sometimes referred to as a campus area network, or
CAN.
144 GREEN Computer Book-8

Features of MAN
• The network size falls intermediate between LANs and WANs.

• A MAN (like a WAN) is not generally owned by a single organization.

• A MAN often acts as a high speed network to allow sharing of regional
resources (similar to a large LAN).

Wide Area Network (WAN)

A WAN contains multiple LANs or MANs connected together across a wide
geographical area. The individual LANs separated by large distances may be
connected by dedicated links, fiber optic cables or satellite links. The Internet
is the best-known example of a public WAN.

Firewall

Internet
Switch

Switch

Web Server

File server File server File server Colour printer Piotter Fax

Features of WAN
• Multiple computers are connected together.

• It connects devices that are separated by a broader geographical area than
a LAN.

• A WAN usually interconnects multiple LANs.

• Communication links between computers are provided by telephone
networks, public data networks, satellites, etc.

GREEN Computer Book-8 145

Network Topology

The network topology is the structure or layout of the communication channels
that connects the various computers on the network. Each computer in the
network is called a node. There are a number of factors that determine the
topology suitable for a given situation.

Bus topology Server Workstation

Bus topology uses one main Terminator Terminator
cable to which all nodes are Printer
directly connected. The main
cable acts as a backbone for the
network. One of the computers
in the network typically acts as
the computer server.

Advantages
• It is easy to connect a computer or peripheral device.
• Cable requirements are relatively small
• Lower installation cost.

Disadvantages

• If the main cable breaks, the entire network goes down.

• This type of network is also difficult to troubleshoot.

• This type of topology is not used for large networks, such as those covering

an entire building.

Computer

Star Topology Hub
Computer
In star topology, each computer is Computer

connected to a central hub using a point-

to-point connection. The central hub can
be a computer server that manages the
network, or it can be a much simpler

device that only makes the connections

between computers over the network Printer
possible.
Computer

146 GREEN Computer Book-8

Advantages
• Star topology is very popular because the startup costs are low.

• It is also easy to add new nodes to the network.

• The network is robust in the sense that if one connection between a
computer and the hub fails, the other connections remain intact.

Disadvantages
• If the central hub fails, however, the entire network goes down.

• It also requires more cable than bus topology and is, therefore, more
expensive.

Computer node

Ring Topology

In ring topology, the computers in the Computer Token Computer
network are connected in a circular node node

fashion, and the data travels in one

direction. Each computer is directly

connected to the next computer, forming

a single pathway for signals through the

network.

Computer node

Advantages

• This type of network is easy to install and manage.

• If there's a problem in the network, it is easy to pinpoint which connection
is defective.

• It is also good for handling high-volume traffic over long distances since
every computer can act as a booster of the signal.

Disadvantages

• On the downside, adding computers to this type of network is more
cumbersome, and if one single computer fails, the entire network goes
down.

GREEN Computer Book-8 147

POINTS TO REMEMBER

1. A computer network consists of a collection of computers, printers and
other equipment that is connected together so that they can communicate
with each other.

2. Primary goal of a computer network is to share resources.
3. Information on one computer can be accessed by other computers in the

network. Repetition of data file on separate PCs can be avoided.
4. A LAN is very useful for sharing resources, such as data storage and

printers.
5. A metropolitan area network, or MAN, consists of a computer network

across an entire city, college campus or small region.
6. A WAN contains multiple LANs or MANs connected together across a

wide geographical area.
7. Network connection devices are the peripheral devices that are required

to connect computers on the network.
8. The existing resources on a network are managed by the server.
9. Workstation is the computer on network that uses the resources

provided by the server computer or other computers.
10. Communication media are the path wires or wireless media through

which data get transmitted.
11. A hub is a simple device that works as a central point to receive the

signals from all the workstations and a server computer.
12. Repeaters are the simple devices that amplify these signals to travel

farther.
13. Bridges are the devices that join network of computers with similar

topologies.
14. Routers are highly intelligent devices that connect different types of

computer network.
15. Gateways connect dissimilar networks. They convert data and repackage

it to meet the requirements of the destination address.
16. The network topology is the structure or layout of the communication

channels that connects various computers on the network.
17. Bus topology uses one main cable to which all nodes are directly

connected.
18. In ring topology, the computers in the network are connected in a

circular fashion, and the data travels in one direction.
19. In star topology, each computer is connected to a central hub using a

point-to-point connection.

148 GREEN Computer Book-8

Exercise

1. Answer the following questions:
a. What is a computer network?
b. List out the types of computer networks.
c. What is LAN? Write its features.
d. Write the differences between MAN and WAN.
e. What are the advantages of a computer network?
f. Write the disadvantages of a computer network.
g. List out the application area of a computer network.
h. Why is computer network important?
i. List out the components required for a computer network.
j. What is network topology? List the types of topology.
k. Write the differences between Ring Topology and Star Topology of
network.

2. Write the full form of the following.

LAN MAN WAN ATM CAN NIC

3. State whether the following statements are “True” or “False”
a. LAN covers a very wide geographical area.

b. MAN is also known as CAN.

c. If the main file server of a computer network breaks down, the entire
system becomes useless.

d. A WAN usually interconnects multiple LANs.

e. Computer network does not allow people to share costly equipment.

f. Bus topology uses one main cable to which all nodes are directly
connected.

4. Write short notes on the following terms:

a. Repeater b. Server c. Workstation d. Router

GREEN Computer Book-8 149

5. Write technical term for the following:

a. The devices that join network of computers with similar topologies.
b. The path wires or wireless media through which data get transmitted.
c. A simple device that works as a central point to receive the signals

from all the workstations and a server computer.
d. The topology uses one main cable to which all nodes are directly

connected.
e. A device that converts digital signal into analog and vice versa.
f. The device that connects dissimilar networks.

6. Draw the figure of LAN, MAN and WAN and label it.

7. Draw and label the figure of Start Topology, Bus Topology and Ring
Topology.

8. Match the following. i. the main able acts as backbone
ii. hub
a. LAN iii. cover very short distance
b. MAN iv. bigger than LAN and small than WAN
c. WAN v. computers are connected in circular fashion
d. Start topology vi. cover very long distance
e. Bus topology
f. Ring topology

150 GREEN Computer Book-8