Computer GK for Competitive Exams: Basics and MCQs

Computer GK covers the basic concepts of computers, hardware and software, memory, operating systems, the internet, networking, cybersecurity and common computer abbreviations. These topics help students prepare for competitive examinations that include computer awareness or general knowledge questions.

This guide explains key computer fundamentals in straightforward language, highlights common exam traps and provides practice MCQs with answers. It is suitable for revision for exams that test basic computer knowledge, including general computer awareness and digital literacy concepts.

Last Updated: 26 October 2026, 03:26 PM IST | Reviewed by Vijay Sah

Computer GK: Quick Facts

Point	Fact
Computer	An electronic device that processes data according to instructions.
CPU	Central Processing Unit; executes instructions and performs processing operations.
ALU	Arithmetic Logic Unit; performs arithmetic and logical operations.
RAM	Volatile main memory that normally loses its contents when power is switched off.
ROM	Non-volatile memory used to retain information without continuous power.
Operating system	System software that manages hardware and provides services for applications.
Input device	A keyboard is a common device for entering data and instructions.
Output device	A monitor displays visual output from a computer.
WWW	World Wide Web; a system of linked resources accessed over the internet.
URL	Uniform Resource Locator; the address used to identify a resource on a network.
HTTP	Hypertext Transfer Protocol, used for transferring web resources.
LAN	Local Area Network, connecting devices within a limited area.
Malware	Software designed to perform harmful or unauthorised activities.

Computer Fundamentals

A computer accepts data, processes it according to instructions, stores information when required and produces results. This general sequence is often described as input, processing, output and storage.

Data and information

Data refers to raw facts, figures or symbols. Information is data organised or processed so that it becomes meaningful. For example, individual marks entered into a computer are data; a calculated result sheet is information.

Characteristics of a computer

Speed: Computers can perform many operations in a short time.
Accuracy: Correct input and instructions generally produce accurate results, although errors can occur because of faulty data or programs.
Storage: Computers can retain large amounts of data on suitable storage devices.
Automation: A computer can carry out a sequence of operations after it has been instructed or programmed.
Consistency: It can repeat the same operation without fatigue, provided its instructions and operating conditions remain suitable.

Computers do not independently guarantee that an answer is correct. Incorrect input, faulty software or inappropriate instructions can produce incorrect results.

Types of computers

Desktop: A personal computer generally designed for use at a fixed workstation.
Laptop: A portable computer with an integrated display and keyboard.
Tablet: A portable device commonly operated through a touchscreen.
Server: A computer that provides data, resources or services to other computers over a network.
Supercomputer: A high-performance system used for computationally demanding tasks such as complex scientific simulations.

Exam Point: A server is defined by the services it provides, not simply by its physical size. A server can be a powerful rack-mounted machine or a computer running server software.

Hardware and Software

Hardware means the physical components of a computer. Software means the programs and instructions that tell the hardware what to do. Both are required for a computer system to perform useful tasks.

Category	Examples	Purpose
Input hardware	Keyboard, mouse, scanner, microphone	Enters data or instructions.
Output hardware	Monitor, printer, speakers	Presents results to the user.
Processing hardware	CPU	Executes instructions and processes data.
Storage hardware	Hard disk, SSD, pen drive	Stores data and files.
System software	Operating system, device drivers	Manages system resources and supports hardware operation.
Application software	Word processor, spreadsheet, web browser	Helps users perform specific tasks.

CPU and its main components

The Central Processing Unit (CPU) executes program instructions. In basic computer studies, two commonly discussed components are the Arithmetic Logic Unit and the Control Unit.

ALU: Performs arithmetic operations, such as addition, and logical comparisons.
Control Unit (CU): Coordinates instruction execution and directs operations within the processor and other system components.
Registers: Small, fast storage locations inside the processor used to hold values and instructions temporarily during processing.

The CPU is often called the brain of the computer in introductory textbooks. This is a teaching analogy, not a statement that a computer thinks like a human brain.

System software and application software

An operating system is system software. Examples include Microsoft Windows, Linux, macOS, Android and iOS. The operating system manages resources such as memory, files and devices, and provides an environment for applications.

Application software is designed for particular user tasks. A word processor helps create documents, a spreadsheet supports calculations and data analysis, and a presentation program helps prepare slides.

Common exam trap: Windows is an operating system, while a word-processing application is application software. A computer can have many applications, but they depend on system software and hardware to run.

Computer Memory and Storage

Memory and storage are related but not identical. Main memory supports active processing, while storage devices retain files and programs for later use.

Term	Meaning	Exam distinction
Bit	A binary digit, either 0 or 1.	The smallest unit of digital data.
Byte	Eight bits.	A common unit for measuring data.
RAM	Random Access Memory.	Usually volatile and used for active work.
ROM	Read-Only Memory.	Non-volatile; the name reflects its traditional use, although some forms can be updated.
Cache memory	Small, fast memory close to or within the processor.	Helps reduce delays when accessing frequently needed data.
HDD	Hard Disk Drive.	Uses magnetic storage and moving mechanical parts.
SSD	Solid-State Drive.	Uses flash memory and has no moving mechanical parts.
Pen drive	Portable USB flash storage device.	Used to transfer and store files.

Volatile and non-volatile memory

Volatile memory requires power to maintain its stored contents. RAM is the standard example. Non-volatile memory retains data when power is removed; ROM and flash storage are examples.

When a computer is switched off, unsaved work held only in RAM may be lost. Saving a file to an SSD or hard drive stores it on a persistent storage device.

Units of digital storage

1 byte = 8 bits.
1 kilobyte (KB) is commonly taught as 1,024 bytes in traditional computer-exam questions.
1 megabyte (MB) = 1,024 KB under the same traditional binary convention.
1 gigabyte (GB) = 1,024 MB under that convention.
1 terabyte (TB) = 1,024 GB under that convention.

In modern storage specifications, decimal units are also used: 1 kB = 1,000 bytes, 1 MB = 1,000,000 bytes and 1 GB = 1,000,000,000 bytes. Binary units such as KiB, MiB and GiB use powers of 1,024. Check the wording of the question before calculating.

Internet, Web and Networking

The internet is a global network of interconnected networks. The World Wide Web is a service that operates over the internet and provides access to linked pages and other resources. The terms internet and web are therefore not interchangeable.

Common internet terms

Website: A collection of related web pages and resources generally associated with a domain.
Web page: An individual document or resource viewed through a web browser.
Web browser: Software used to access and display web content, such as Chrome, Firefox, Safari or Edge.
Search engine: A service that helps users find indexed information on the web.
URL: An address that identifies a resource, such as a web page.
IP address: A numerical or alphanumeric network address used to identify an interface or endpoint for internet protocol communication.
ISP: Internet Service Provider, a company or organisation that provides internet access or related services.

HTTP, HTTPS and email

HTTP stands for Hypertext Transfer Protocol. HTTPS is HTTP protected by TLS, which helps secure communication between a browser and a website. HTTPS does not by itself prove that a website is honest or that every item on it is trustworthy.

Email means electronic mail. A typical email address contains a local part, the @ symbol and a domain, as in name@example.com. The example is illustrative and is not a real contact address for JobSearchKing.

Exam Point: A browser opens web pages; a search engine helps find information; and a website is a collection of web resources. These functions are related but different.

Types of computer networks

Network	Full form	General coverage
PAN	Personal Area Network	Personal devices in a short-range area.
LAN	Local Area Network	A limited area, such as a home, office or school.
MAN	Metropolitan Area Network	A town or city-scale area in common textbook descriptions.
WAN	Wide Area Network	A large geographical area; it may connect networks across regions or countries.

Wi-Fi is a technology used for wireless local networking. It is not another name for the internet: a device can connect to a Wi-Fi network even when that network has no internet access.

Cybersecurity and Safe Computing

Computer security involves protecting devices, accounts, networks and information against unauthorised access, damage or misuse. Basic awareness questions often test the meaning of malware, phishing, antivirus software, passwords and backups.

Virus: A type of malicious code that attaches to a host file or program and may spread when the infected host is run.
Worm: Malware that can spread between systems or devices, often by exploiting network or software weaknesses.
Trojan horse: Malicious software disguised as, or presented as, legitimate software.
Ransomware: Malware that can lock access to files or systems, commonly by encrypting data, and demands payment.
Phishing: A deceptive attempt to obtain sensitive information or persuade a person to take an unsafe action, often through messages or fake websites.
Firewall: A security system that monitors and controls network traffic according to defined rules.
Antivirus or anti-malware software: Tools designed to detect, block or remove certain malicious software.
Backup: A separate copy of data that can help recover information after accidental deletion, device failure or an attack.

Safe computing habits

Use long, unique passwords and a password manager where appropriate.
Enable multi-factor authentication for important accounts when available.
Keep the operating system, browser and other software updated.
Do not open unexpected attachments or enter passwords through suspicious links.
Check website addresses carefully before submitting personal or financial information.
Keep important backups separate from the device being backed up.
Never share one-time passwords or authentication codes with people who contact you unexpectedly.

Exam Point: Phishing is a social-engineering technique, while a firewall filters network traffic. Antivirus software and backups serve different purposes, so they should not be treated as substitutes for each other.

Important Computer Abbreviations

Abbreviation	Full form
CPU	Central Processing Unit
ALU	Arithmetic Logic Unit
CU	Control Unit
RAM	Random Access Memory
ROM	Read-Only Memory
USB	Universal Serial Bus
OS	Operating System
GUI	Graphical User Interface
WWW	World Wide Web
URL	Uniform Resource Locator
HTTP	Hypertext Transfer Protocol
HTTPS	Hypertext Transfer Protocol Secure
HTML	HyperText Markup Language
IP	Internet Protocol
ISP	Internet Service Provider
LAN	Local Area Network
WAN	Wide Area Network
PDF	Portable Document Format
BIOS	Basic Input/Output System
AI	Artificial Intelligence

Computer GK One-Liners

A keyboard is an input device; a monitor is an output device.
A printer produces a hard copy of a document or image.
A scanner converts paper-based text or images into digital form.
The operating system manages resources and provides services to applications.
RAM is normally volatile, while SSD storage is non-volatile.
Eight bits make one byte.
A browser and a search engine have different functions.
HTTPS protects the connection using TLS, but does not guarantee that a website is legitimate.
LAN refers to a network within a limited geographical area.
A backup helps restore data; it is not the same as antivirus protection.

Computer GK MCQs with Answers

Test your understanding with these practice questions. Each question is based on the concepts explained above.

Q1. What is the full form of CPU?
A. Central Program Utility
B. Computer Processing Unit
C. Central Processing Unit
D. Control Program Unit
Correct Answer: C. Central Processing Unit

Q2. Which of the following is generally volatile memory?
A. RAM
B. SSD
C. Pen drive
D. Hard disk drive
Correct Answer: A. RAM

Q3. Which component performs arithmetic and logical operations?
A. Monitor
B. ALU
C. Keyboard
D. Printer
Correct Answer: B. ALU

Q4. Which option is an example of application software?
A. CPU
B. RAM
C. Device driver
D. Word processor
Correct Answer: D. Word processor

Q5. What does WWW stand for?
A. World Wide Web
B. Web World Window
C. Wide Web Workspace
D. World Web Wire
Correct Answer: A. World Wide Web

Q6. Which network usually covers a limited area such as an office or school?
A. WAN
B. MAN
C. LAN
D. Global network only
Correct Answer: C. LAN

Q7. What is the main purpose of a web browser?
A. To replace computer memory
B. To access and display web content
C. To physically connect a printer
D. To supply electricity to the CPU
Correct Answer: B. To access and display web content

Q8. Which term describes a deceptive attempt to obtain sensitive information through a message or fake website?
A. Formatting
B. Defragmentation
C. Backup
D. Phishing
Correct Answer: D. Phishing

Q9. How many bits are in one byte?
A. 4
B. 8
C. 16
D. 32
Correct Answer: B. 8

Q10. Which statement about HTTPS is correct?
A. It means a website can never be fraudulent.
B. It is used only for offline files.
C. It uses TLS to help protect communication between a browser and a website.
D. It is a type of computer monitor.
Correct Answer: C. It uses TLS to help protect communication between a browser and a website.

Frequently Asked Questions About Computer GK

What is Computer GK?

Computer GK is basic knowledge about computer hardware, software, memory, operating systems, internet concepts, networking, security and related terminology. It is useful for examinations that include computer awareness.

What is the difference between RAM and ROM?

RAM is generally volatile working memory used while programs are running. ROM is non-volatile memory that retains its contents without continuous power, although the ways it can be written or updated depend on the type.

What is the difference between the internet and the World Wide Web?

The internet is the underlying network of interconnected networks. The World Wide Web is a system of linked pages and resources accessed through the internet.

What is the difference between a virus and phishing?

A virus is a type of malicious code, while phishing is a deceptive attempt to obtain information or trigger an unsafe action. A phishing message may deliver malware, but phishing does not always involve a virus.

How can students prepare for Computer GK questions?

Study definitions and abbreviations, understand differences between similar terms, revise memory and networking concepts, and practise MCQs. Review why each answer is correct rather than memorising option letters.

Final Takeaway

For Computer GK, focus first on the differences between hardware and software, RAM and storage, browsers and search engines, and the internet and the World Wide Web. Learn the common abbreviations and practise questions on cybersecurity. These fundamentals also provide a useful starting point for computer-awareness study and digital literacy courses.

Sources referred: NIELIT: Awareness in Computer Concepts, NIELIT: Course on Computer Concepts (CCC), NCERT: Computer Science textbook resources.