L- 8 Computer Viruses/ Class 4th Computer

 

Class – 4^th

Subject : Computer Science

L- 8 Computer Viruses

A. Fill in the blanks :

[ Data, bottom, virus, websites, emails, software ]

 

1. A virus is a man-made computer program that infects a file or

program on our computers.

2. Most of the viruses spread through emails.

3. Thousands of insecure websites can infect computer with viruses.

4. Letters look like they are falling to the bottom of the screen.

5. A computer virus can damage Data or software on the computer.

B. State T for True and F for False :

1. Virus enters in system through atmosphere.                        FALSE

2. Computer's hardware also gets infected with virus.        FALSE

3. Virus can damage hard disk.                                                           TRUE

4. Anti-virus installation can stop virus.                                        TRUE

5. Trojan Horses replicate themselves.                                          FALSE

C. Answer the following questions :

1. What is virus? Write any three types.

Ans: A virus is a man-made computer program that infects a file or program on our computers. Each time the infected program is run, the virus is also triggered. It replicates or spreads itself by infecting other programs on the same computer.

Types of Computer Viruses: 

1)  Boot viruses 

2)  Polymorphic viruses 

3)  Macro Virus 

4)  Email Virus 

5)  Trojans horses

6)  Worms

 

 

2. Write any three symptoms of computer viruses.

Ans: Symptoms of Computer Virus

1. Letters look like they are falling to the bottom of the screen.

2. The computer system become slow.

3. The size of available free memory reduces.

4. The hard disk runs out of space.

5. The computer does not boot.

6. Program files get bigger in size.

7. Your computer crashes or suddenly re-boots itself.

 

3. What are Trojan Horses?

Ans: This is a generally non-self replicating type of code which when executed, causes loss or theft of data and possible system harm. Example as we all know E-banking is very common, so its vulnerability of tracing your login details whenever your PC is working without the support of strong antivirus.

 

4. Define anti-virus program.

Ans: Antivirus software is a computer software used to prevent, detect and remove malicious software from computer.Antivirus software detects and removes computer viruses from the system.

 

5. Write any three sources of virus.

Ans: The following are the main sources of a Computer Virus :

1)  Infected Flash Drives or Disks

2)  Email Attachments 

3)  Infected websites

4)  Networks 

5)  Pirated Software

 

D. Write the names any four anti virus softwares.

1)  Norto

2)  AVG

3)   Mcafee

4)  Avira

5)   Bitdefender

6)   Pandasecurity

7)   Eset

8)   QuickHeal

9)  Kaspersky

10)                Immunet