Computers Basic MCQs Set-27

A scanner is a computer peripheral device that is used to convert physical documents or images into digital formats. It works by optically scanning the document or image and capturing its contents. The resulting digital data can then be stored, manipulated, or transmitted electronically.

Scanners are commonly used in various applications, such as:

1. Document Scanning: Scanners can digitize paper documents, including letters, contracts, invoices, or other printed materials. This allows for efficient storage, retrieval, and sharing of digital documents.

2. Image Scanning: Scanners can capture photographs, illustrations, or any other type of printed image, converting them into digital format for editing, archiving, or sharing online.

3. Optical Character Recognition (OCR): Some scanners incorporate OCR technology, which enables the conversion of scanned text into editable and searchable digital text. This is useful for converting printed documents into editable files or extracting information from scanned documents.

4. Art and Design: Scanners are used by artists, designers, and photographers to capture physical artwork, sketches, or photographic prints. This allows for further digital editing, manipulation, or reproduction.

Scanners come in various types, including flatbed scanners, sheetfed scanners, handheld scanners, and specialized scanners for specific applications (e.g., film scanners for negatives and slides). They are typically connected to a computer via USB or other interfaces, and the scanned data is processed using scanning software that often comes bundled with the scanner or is provided by the manufacturer.

The resulting digital scans can be saved in common file formats such as JPEG, PDF, TIFF, or PNG, depending on the desired quality, compression, and compatibility requirements.

Overall, scanners are essential tools for converting physical documents or images into electronic form, enabling easier storage, editing, and sharing of information in the digital world.

The computer abbreviation "KB" usually means "kilobyte."

A kilobyte is a unit of digital information storage that represents approximately 1,000 bytes. It is commonly used to measure the size of files, memory capacity, or data transfer rates in computing.

The prefix "kilo" in the International System of Units (SI) denotes a factor of 1,000. However, in the context of computing, the term "kilobyte" is often used colloquially to represent 2^10 (1,024) bytes, reflecting the binary nature of computer systems. This is due to the historical convention of using binary rather than decimal calculations in computing.

It's worth noting that the use of kilobytes can sometimes lead to confusion or ambiguity, especially when discussing storage capacity or data transfer rates. In recent years, there has been a shift towards using the SI prefix "kibi" (symbol: Ki) to represent 2^10 (1,024) bytes, while reserving "kilo" for decimal usage. This helps to distinguish between the binary and decimal interpretations of the term.

In summary, the computer abbreviation "KB" commonly refers to a kilobyte, which is a unit of digital information storage equivalent to approximately 1,000 bytes or 2^10 (1,024) bytes, depending on the context and the convention being followed.

Spoofing techniques can be employed for both legitimate and malicious purposes. Legitimate uses of spoofing include testing network security or conducting authorized penetration testing. However, malicious actors often use spoofing techniques to carry out scams, phishing attacks, identity theft, or to gain unauthorized access to systems or sensitive information.

Collecting personal information and effectively posing as another individual is known as the crime of "identity theft."

Identity theft occurs when someone unlawfully obtains and uses another person's personal information, such as their name, Social Security number, credit card details, or other identifying data, without their consent. The goal of identity theft is typically to commit fraudulent activities, financial fraud, or gain unauthorized access to resources or services in the victim's name.

Identity theft can have severe consequences for the victim, including financial loss, damage to their credit history, legal complications, and emotional distress. Some common methods used to collect personal information for identity theft include:

1. Phishing: Sending fraudulent emails or creating fake websites that appear legitimate to trick individuals into providing their personal information, such as passwords or credit card numbers.

2. Data Breaches: Unauthorized access to databases containing personal information, often through hacking or exploiting security vulnerabilities, to obtain a large amount of data for identity theft purposes.

3. Social Engineering: Manipulating individuals through deception or psychological tactics to reveal personal information, such as posing as a legitimate entity over the phone or in person.

4. Skimming: Illegally obtaining credit card information by using devices that capture card details during transactions, often in places like ATMs or point-of-sale terminals.

Identity theft is a serious crime that can have a significant impact on individuals, businesses, and society as a whole. Many jurisdictions have specific laws and penalties in place to combat identity theft and protect victims. Preventive measures such as using strong, unique passwords, being cautious with sharing personal information, regularly monitoring financial accounts, and promptly reporting suspicious activity can help mitigate the risk of identity theft.

Malicious software is commonly known as "malware."

Malware is a broad term that encompasses various types of malicious software designed to disrupt, damage, or gain unauthorized access to computer systems, networks, or data. It is created with malicious intent by individuals or groups referred to as "cybercriminals."

There are several categories of malware, including:

1. Viruses: Malicious programs that infect other files or programs by attaching themselves to them and spreading when the infected files are executed.

2. Worms: Self-replicating programs that spread across networks or systems, typically exploiting security vulnerabilities, to infect other devices and propagate themselves.

3. Trojans: Programs that masquerade as legitimate software or files but contain hidden malicious functionality. Trojans often trick users into executing or installing them, giving cybercriminals unauthorized access to the compromised system.

4. Ransomware: Malware that encrypts files on a victim's system, rendering them inaccessible until a ransom is paid. Ransomware attacks are designed to extort money from individuals or organizations.

5. Spyware: Software that secretly gathers information about a user's activities, such as browsing habits, keystrokes, or personal information, and sends it to a remote attacker.

6. Adware: Software that displays unwanted advertisements on a user's system, often in an intrusive or deceptive manner. Adware may also collect user data to deliver targeted advertisements.

7. Rootkits: Malicious programs that gain unauthorized administrative access to a system and hide their presence, making them difficult to detect or remove. Rootkits are often used to facilitate other types of malware or maintain persistent access.

These are just a few examples of the many forms of malware that exist. Cybercriminals continually develop new techniques and variants to evade detection and exploit vulnerabilities.

To protect against malware, it is crucial to employ multiple layers of defense, including using reputable antivirus and anti-malware software, keeping software and operating systems up to date, being cautious when downloading or executing files from untrusted sources, and practicing safe browsing habits. Regular backups and education about safe computing practices are also essential to mitigate the risks associated with malware.

A program that performs a useful task while simultaneously allowing destructive acts is commonly referred to as a "Trojan horse" or simply a "Trojan."

A Trojan is a type of malicious software that masquerades as a legitimate program or file, tricking users into executing or installing it. It typically appears as something desirable or beneficial, enticing users to open it or run it. Once executed, the Trojan performs its intended useful task, such as providing a specific functionality or utility that appears harmless or helpful.

However, alongside its seemingly useful functionality, the Trojan also carries out malicious activities without the user's knowledge or consent. These destructive acts can vary depending on the specific Trojan and its purpose. Examples of destructive acts that a Trojan may perform include:

1. Data Theft: Trojans can secretly collect sensitive information from infected systems, such as login credentials, financial data, personal information, or browsing habits. This stolen data can be used for identity theft, financial fraud, or other malicious purposes.

2. System Modification: Trojans can modify system settings, configurations, or critical files, leading to system instability, crashes, or unauthorized access to the infected system.

3. Remote Control: Some Trojans enable unauthorized remote access to infected systems, allowing attackers to control the system, execute commands, install additional malware, or use the system as a part of a botnet for malicious activities.

4. Keylogging: Trojans may include keyloggers that record keystrokes entered by users, capturing sensitive information such as passwords, credit card numbers, or other confidential data.

The term "Trojan horse" originates from Greek mythology, where the Greeks used a deceptive wooden horse to gain entry into the city of Troy. Similarly, Trojan malware deceives users by appearing harmless or useful, while carrying out malicious actions in the background.

To protect against Trojans, it is crucial to employ robust security measures, including using reputable antivirus software, regularly updating software and operating systems, being cautious when downloading or executing files from untrusted sources, and practicing safe computing habits to minimize the risk of infection.

An intentionally disruptive program that spreads from program to program or from disk to disk is known as a "computer virus."

Computer viruses are malicious programs designed to infect other programs or files and replicate themselves without the knowledge or consent of the user. They are typically created with the intent to cause harm, disrupt computer systems, steal information, or gain unauthorized access.

Computer viruses can spread through various means, such as email attachments, infected software downloads, compromised websites, or removable storage media. Once a virus infects a host program or file, it can replicate itself and spread to other programs, files, or systems, potentially causing damage or compromising the security of the affected systems.

Some common types of computer viruses include:

1. File Infector Viruses: These viruses attach themselves to executable files and infect other files when the infected file is executed.

2. Macro Viruses: Macro viruses infect documents and exploit the macro functionality in applications like Microsoft Word or Excel. They can spread through infected documents and macros, causing harm when the document is opened.

3. Boot Sector Viruses: These viruses infect the boot sector of a disk or a computer's Master Boot Record (MBR). When the infected disk or system is booted, the virus gets loaded into memory and can spread to other disks or systems.

4. Polymorphic Viruses: Polymorphic viruses have the ability to change their code or appearance to avoid detection by antivirus software, making them more challenging to identify and remove.

It is important to have up-to-date antivirus software and practice safe computing habits, such as avoiding suspicious email attachments, downloading files from trusted sources, and regularly updating software, to mitigate the risk of computer virus infections and their disruptive effects.

In 1999, the Melissa virus was a widely publicized computer virus that caused significant disruption and garnered substantial media attention. Named after an exotic dancer in Florida, the Melissa virus was created by David L. Smith and distributed via email.

The Melissa virus was a macro-based virus that targeted Microsoft Word documents. It spread primarily through infected email attachments that were sent to other users. When the recipient opened the infected document, the virus would activate and replicate itself by sending copies of the infected document to the first 50 email addresses found in the recipient's Microsoft Outlook address book.

The rapid spread of the Melissa virus led to a significant increase in email traffic and overloaded email servers, causing disruptions in email communication for many individuals and organizations. The virus quickly became a global epidemic, affecting numerous businesses and government agencies.

The impact of the Melissa virus was substantial due to its ability to spread quickly and its disruptive nature. It raised awareness about the vulnerability of email systems and highlighted the need for improved security measures to combat the growing threat of computer viruses and malware.

The Melissa virus also served as a wake-up call for organizations to implement better security practices, such as regularly updating antivirus software, educating users about safe computing practices, and implementing email filters and content scanning to detect and prevent the spread of malicious attachments.

The incident involving the Melissa virus resulted in legal consequences for its creator. David L. Smith was arrested and sentenced to 20 months in federal prison for his role in creating and distributing the virus. The case highlighted the legal ramifications of creating and spreading computer viruses and set a precedent for prosecuting individuals involved in cybercriminal activities.

The type of virus that uses computer hosts to reproduce itself is called a "worm."

A computer worm is a type of malicious software that can self-replicate and spread across computer networks without any user intervention. Unlike traditional viruses that typically require user action to propagate (such as executing an infected file or opening an infected email attachment), worms have the ability to independently find and infect vulnerable systems.

Once a computer worm gains access to a host system, it can automatically replicate itself and spread to other connected systems, often using network vulnerabilities or security weaknesses. Worms can exploit various communication protocols, such as email, instant messaging, or file-sharing networks, to propagate and infect new hosts.

The primary purpose of worms is to propagate rapidly and infect as many systems as possible. This behavior can lead to a significant disruption of network operations, consume network bandwidth, and compromise the security and stability of affected systems.

It is important to note that worms are distinct from viruses, which typically require human interaction to spread. Worms, on the other hand, are capable of spreading autonomously and can exploit network vulnerabilities to quickly propagate across a wide range of systems.