CLASS-7th

COMPUTER

CHAPTER-1

COMPUTER

1. Defines the following:-

a) Trojan horse:- Trojan horse virus comes as a friendly program(as a game) however it is very dangerous as it

destroys all the data on your computer.

b) Rootkit:- rootkit virus is a program that hides in a computer and allows someone from a remote

location to take full control of your computer.

c) sleeper:- the sleeper virus is known to steal your personal and financial information. This virus is

programmed to target large networks only.

d) adware:- adware is a program that displays an unwanted advertisement on internet services. If you click

on advertisement, virus will install on your computer.

e) spyware:- a spyware is a program placed on computer without the user’s knowledge that secretly

collects information and send the same to some outside source while the user is online.

ANSWER THE FOLLOWING QUESTIONS:-

1. What is computer virus?

Ans:- VIRUS stands for vital information resources under seize. Viruses are programs which are

created deliberately to damage critical information and data. Once virus is in your computer, your

files and data get damaged.

2. Why do we use antivirus program?

Ans:- An antivirus program protects a computer against virus ,identifying and removing any

computer virus found in the memory, storage media, or incoming files.

3. What is boot sector virus?

Ans:- This virus attaches itself to the boot sector of the disk. This sector is a part of the disk where

start-up instructions and the file allocation tables are kept. This sector is read and loaded into the

memory every time the disk is booted. This virus is also very dangerous.

4. Write briefly about the sources of computer virus?

Ans:- a) E-MAIL:- E-MAIL viruses are spread by files attached to e-mail messages.

b) INTERNET DOWNLOAD:- if something you want to download, is infected by virus, then virus

comes to your computer system.

c) DISTRIBUTION OF SOFTWARE:- if your computer is virus infected and you copy a software on a

pendrive, the virus of your computer also get copied on the pendrive.

5. How does email virus spread?

Ans:- E-MAIL viruses are spread by the files attached to email messages. when you open an email

attachment that contains a virus, the virus spreads to your computer. If you forward the

attachment to other people ,their computers will also get affected when they open the

attachment.

6. What is ransomware virus?

Ans:- Ransomware virus is a virus that restricts access to your computer system and demands a

ransom (money) to be paid in order to remove the restrictions.

7. Write any two precautions that should be taken to prevent computer virus?

Ans:- a) do not start a computer with removable media.

b) never open an e-mail attachment, unless it is from a trusted source.

c) always download files from trusted websites.

d) install an antivirus program on all your computers.

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