Computer Awareness Previous Year Questions (PYQ) with Answers

The correct answer is C, To manage hardware and software resources. An operating system is the system software that loads when a laptop starts and then runs the machine: it shares out memory, decides which program gets the processor and for how long, keeps files and folders in order on the disk, talks to the keyboard, screen and printer through device drivers, and gives the user an interface. Every other program, from a word processor to a game, runs on top of it and asks it for whatever it needs. Windows, macOS, Linux, Ubuntu and Android are common examples. A is wrong because typing documents is the work of an application such as MS-Word. B is wrong because a browser is only one of many programs the operating system supports, not its purpose. D is wrong because video editing is done by application software such as a video editor. Exam tip: an operating system is system software and works as the bridge between the user, the applications and the hardware.

The correct answer is B, 010010. The 2's complement of a binary number is found in two steps: flip every bit to get the 1's complement, then add 1. Flipping 101110 gives 010001, and 010001 + 1 = 010010. A quick check confirms it: 101110 is 46 and 010010 is 18, and 46 + 18 = 64, which is 2⁶ for a six-bit number, exactly as it should be. Computers use the 2's complement to store negative numbers and to do subtraction by addition, which keeps their circuits simple. A shortcut also works: copy the bits from the right up to and including the first 1, then flip all the rest. A is wrong because 010011 adds 2 instead of 1 to the 1's complement. C is wrong because 110001 leaves the leftmost bit unflipped. D is wrong because 010001 is only the 1's complement; the final +1 is missing. Exam tip: 2's complement = flip all bits, then add 1; a number plus its 2's complement equals 2ⁿ.

The correct answer is B, To prevent unauthorised access to a private network. A firewall stands between a trusted private network and an untrusted one such as the internet, and checks the data going in and out. Traffic that matches its security rules is allowed and the rest is blocked, much like a guard at a gate. It can be hardware, such as a separate device or a feature of a router, or software, such as the firewall built into Windows. The name comes from the fire-resistant walls in buildings that stop a fire from spreading from one part to another. A is wrong because a firewall does not make the connection faster; checking traffic can even slow it slightly. C is wrong because finding and removing viruses is the job of antivirus software, which works on files already on a computer. D is wrong because storing passwords safely is the work of a password manager. Exam tip: firewall = gatekeeper of network traffic; antivirus = cleaner of infected files.

The correct answer is A, SRAM. Static RAM stores each bit in a flip-flop circuit made of several transistors, usually six, so the bit stays put as long as the power is on and never needs refreshing. That makes SRAM very fast, but also costly and bulky, so it is used in small amounts as cache memory inside the processor. Both kinds of RAM are volatile and lose their data when the power goes off. B is wrong because DRAM stores each bit as a charge in a tiny capacitor that slowly leaks, so it must be refreshed every few milliseconds; it is cheaper and denser, and serves as the main memory. C is wrong because flash memory is non-volatile storage used in pen drives, memory cards and SSDs, and it is slower than RAM. D is wrong because ROM is read-only, non-volatile memory that holds start-up instructions, not a type of RAM. Exam tip: SRAM = static, fast, no refresh, used as cache; DRAM = dynamic, needs refresh, used as main memory.

The correct answer is D, Hard Disk. A hard disk is a secondary storage device that keeps programs and files permanently, even when the power is off, and it sits outside the processor. The CPU (Central Processing Unit), often called the brain of the computer, is made of the Arithmetic Logic Unit, the Control Unit and a set of small, very fast registers. Modern processors also carry cache memory on the same chip to hold the data and instructions they need most often. Data from the hard disk is first loaded into RAM, then moved into the cache and registers before the CPU works on it. A is wrong because the ALU does all arithmetic and logical work such as addition and comparison. B is wrong because the Control Unit fetches and decodes instructions and directs every operation. C is wrong because cache memory is built into the processor chip and is the fastest memory after the registers. Exam tip: CPU = ALU + CU + registers (with cache); hard disk = secondary storage.

The correct answer is A, F5. In Microsoft PowerPoint, pressing F5 starts the slide show from the first slide, whichever slide you are working on at that moment. The same command sits on the Slide Show tab as 'From Beginning'. Its close partner is Shift + F5, which starts the show from the current slide, and paper setters like to place the two side by side. During the show, Esc ends the presentation, and pressing B or the full stop key turns the screen black until you press it again. B is wrong because Alt + Tab switches between open windows in Windows. C is wrong because Ctrl + P opens the Print option in almost every Office program. D is wrong because Shift + F5 begins the show from the current slide, not from the beginning. Exam tip: F5 = start from the beginning, Shift + F5 = start from the current slide, Esc = end the show.

The correct answer is C, Ctrl + M. In Microsoft PowerPoint, pressing Ctrl + M adds a new slide right after the one you are on, using the layout of the current slide. Think of M for 'more slides', which makes it easy to recall. Other shortcuts worth knowing in PowerPoint are F5 to start the show from the first slide, Shift + F5 to start from the current slide, Esc to end the show, and Ctrl + S to save. Option A is wrong because Ctrl + N opens a brand new blank presentation, not a slide. Option B is wrong because Ctrl + D duplicates the slide that is selected, copying its content as well. Option D is wrong because Ctrl + I turns the selected text italic, just as it does in Word and Excel. Exam tip: Ctrl + M new slide, Ctrl + D duplicate slide, Ctrl + N new file, F5 to run the slide show.

The correct answer is D, Both I and II. The Post Office Protocol, best known in its third version POP3, lets a mail client download messages from a mail server, and it works in two modes. In the delete mode the message is removed from the server once it has been downloaded, which suits a person who always reads mail on the same computer. In the keep mode a copy stays on the server after downloading, so the same mail can be read again from another device. POP3 uses port 110, or port 995 when secured with SSL. Option A is wrong because both modes do exist in POP. Option B is wrong because keep mode is not the only one; delete mode is the default in many clients. Option C is wrong because delete mode is not the only one either. Exam tip: POP3 downloads mail and offers delete and keep modes, IMAP keeps mail on the server and syncs it across devices, and SMTP is the protocol that sends mail.

The correct answer is C, Memory Card. A memory card keeps data in flash memory, a semiconductor chip with no moving parts, so it is solid-state storage and not magnetic. The data sits as trapped charge in floating-gate transistors, which is why SD cards, pen drives and solid-state drives are fast, silent and able to take a knock. Magnetic storage works quite differently: it records data as patterns of magnetised spots on a coated surface that a read-write head passes over. Option A is wrong because the Winchester disk is the early IBM name for the sealed hard disk drive, which is magnetic. Option B is wrong because a floppy drive writes on a thin magnetic plastic disc. Option D is wrong because magnetic tape, still used for archives and backups, is a plastic ribbon with a magnetic coating. Exam tip: sort storage by how it records — magnetic (hard disk, floppy, tape), optical (CD, DVD, Blu-ray) and solid-state or flash (memory card, pen drive, SSD).

The correct answer is C, HTTP. HTTP stands for HyperText Transfer Protocol and it is the set of rules by which a browser asks a web server for a page and the server sends it back, which is how data on the World Wide Web is reached. It was developed by Tim Berners-Lee, who also created the World Wide Web in 1989, and it works on port 80, while its secure form HTTPS uses encryption and port 443. A is wrong because DNS, the Domain Name System, only turns a name such as gk24.in into the numeric IP address of the server. B is wrong because SNMP, the Simple Network Management Protocol, is used by administrators to watch and manage routers, switches and other network devices. D is wrong because FTP, the File Transfer Protocol, moves whole files between a computer and a server rather than serving web pages. Exam tip: HTTP for web pages, FTP for file transfer, SMTP to send mail, POP3 and IMAP to receive it.

The correct answer is B, Change Case. In MS-Word 2016 the button marked 'Aa' in the Font group of the Home tab opens the Change Case menu, which rewrites the selected text without retyping it. Its five choices are Sentence case, lowercase, UPPERCASE, Capitalize Each Word and tOGGLE cASE, and the keyboard shortcut Shift + F3 moves the selection through the main cases one after another. A is wrong because Text Effects and Typography is the blue glowing 'A' that adds shadow, reflection and outline to text. C is wrong because Clear All Formatting is the 'A' with a small eraser, which strips the text back to plain formatting. D is wrong because Strikethrough is shown as 'abc' with a line drawn through it and simply crosses out the text. Exam tip: in the Font group remember Shift + F3 for change case, Ctrl + B for bold, Ctrl + I for italic and Ctrl + U for underline.

The correct answer is A, .tmp. A file with the .tmp extension is a temporary file, created by a program while it is working and normally deleted once the work is done. Word processors, browsers and installers make them to hold data they may need for recovery, and Windows keeps many of them in the Temp folder, which can be cleared safely. Option B is wrong because .txt is a plain text file that stores unformatted text and opens in Notepad. Option C is wrong because .tnt is not a standard file extension at all. Option D is wrong because .tar is an archive format from Unix that bundles many files into one, often compressed further as .tar.gz. Questions on extensions come up in every shift, so learn the common ones: .docx for Word, .xlsx for Excel, .pptx for PowerPoint, .exe for a program and .bak for a backup. Exam tip: .tmp is temporary, .bak is a backup and .tar is an archive.

The correct answer is A, Windows. Windows is proprietary, or closed-source: Microsoft keeps its source code private and sells it under a licence that does not let users study, change or redistribute the code. An open-source operating system publishes its source code under a licence that allows anyone to read it, modify it and share it, usually free of cost. Option B is wrong because Ubuntu is a free Linux distribution released by Canonical under open-source licences, widely used on desktops and servers. Option C is wrong because Android is built on the Linux kernel and its core is released as the Android Open Source Project, which is why phone makers can adapt it. Option D is wrong because Linux is the classic example: Linus Torvalds released the kernel in 1991 under the GNU General Public License, and Fedora, Debian and Red Hat all grew from it. Exam tip: closed-source - Windows, macOS and iOS; open-source - Linux, Ubuntu, Fedora and Android.

The correct answer is D, Secondary. A hard disk is secondary storage: the CPU cannot work on its contents directly, and data must first be copied into main memory. Secondary storage is non-volatile, so it keeps files, programs and the operating system even after the power is switched off, and it is far larger and cheaper per gigabyte than RAM, though much slower. A hard disk drive stores data magnetically on spinning platters, with a read-write head moving over the tracks and sectors; solid-state drives, pen drives, CDs and memory cards are secondary storage as well. Option A is wrong because tertiary storage means robotic tape libraries and similar archival systems used for very large backups. Option B is wrong because off-line storage is a removable medium kept away from the computer, such as a tape or a disc on a shelf. Option C is wrong because primary storage means RAM, ROM and cache, which the processor reaches directly. Exam tip: RAM is primary and volatile, hard disk is secondary and non-volatile.

The correct answer is B, Operating system. Ubuntu is a free, open-source operating system built on the Linux kernel and based on the Debian distribution. It was first released in 2004 by Canonical, and its name comes from a Nguni Bantu word of southern Africa meaning humanity towards others. An operating system is the master software that starts the machine and manages its memory, files, processor time and devices; Ubuntu does this job on desktops, laptops, servers and cloud machines, and is popular because it costs nothing and its source code is open. A is wrong because malware means harmful software such as viruses, worms and ransomware. C is wrong because an external hard drive is a piece of hardware used to store data outside the computer. D is wrong because a web browser is an application like Chrome, Firefox or Edge that opens web pages. Exam tip: common Linux distributions are Ubuntu, Fedora, Debian and Red Hat; Windows, macOS and Android are other operating systems.

The correct answer is C, spam. Unwanted bulk messages sent to many people to advertise something are called spam. Spam usually arrives as e-mail, but the same word is used for unwanted SMS, blog comments and social media messages. Mail services run spam filters that study the sender, the subject line and the words used, and move such mail to a separate Spam or Junk folder so that it never reaches the inbox. Spam that pretends to come from a bank and asks for passwords or card details is called phishing, and a person who sends spam is a spammer. Option A is wrong because a virus is a harmful program that copies itself into other files and damages data. Option B is wrong because unzip only means opening a compressed file such as a .zip archive. Option D is wrong because a URL is the address of a web page. Exam tip: unwanted bulk mail is spam, while fake mail that asks for your details is phishing.

The correct answer is D, Ministry of Education. The National Digital Library of India is a single window that brings together lakhs of learning resources, from school books to research papers, and lets a student search them free of cost in many Indian languages. It is developed by IIT Kharagpur under the National Mission on Education through Information and Communication Technology, a mission of the Ministry of Education; the ministry was called the Ministry of Human Resource Development when the library was launched and was renamed in 2020. Option A is wrong because the Ministry of Finance handles the budget, taxes and public spending, not education platforms. Option B is wrong because India has no ministry of that name; Science and Technology is a separate ministry of its own. Option C is wrong because the electronics and information technology ministry runs Digital India, e-governance services and BharatNet, but not this library. Exam tip: National Digital Library of India means IIT Kharagpur, the NMEICT mission and the Ministry of Education.

The correct answer is C, Local Area Network. A LAN joins computers and devices inside a small area such as one room, one building or a campus. It usually runs on Ethernet cable or Wi-Fi, is owned and managed by a single organisation, and gives a high data transfer rate with very few errors, which is why offices, schools and cyber cafes use it. Networks are classed by the area they cover: PAN for one person's own devices, LAN for a building, MAN for a city and WAN for a country or the world, the internet being the largest WAN. Option A is wrong because 'Line Area Network' is not a networking term. Option B is wrong because no class of network is called a 'Linear Area Network'. Option D is wrong because 'Land Area Network' does not exist either. Exam tip: learn the four by rising size — PAN, LAN, MAN, WAN — and remember the LAN is the one limited to a single building or campus.

The correct answer is D, Toggle Keys. A toggle key switches a feature on with one press and off with the next, so it has two states and keeps whichever one you left it in. Caps Lock, Num Lock, Scroll Lock and the Insert key work this way, and most keyboards carry a small indicator light that glows while the feature is on. Caps Lock, for instance, holds capital letters until it is pressed a second time. Option A is wrong because navigation keys move the cursor or the view: the four arrow keys with Home, End, Page Up and Page Down. Option B is not a standard class; keys such as Enter, Esc, Tab and the Windows key are grouped as control or special keys, and none of them stay switched on. Option C is wrong because the function keys are F1 to F12, which run one command each time they are pressed. Exam tip: the four toggle keys are Caps Lock, Num Lock, Scroll Lock and Insert.

The correct answer is D, 50097. Hexadecimal is base sixteen, so the four places of C3B1 carry the weights 4096, 256, 16 and 1 from left to right, and the letters stand for numbers: A is 10, B is 11, C is 12, D is 13, E is 14 and F is 15. Putting the digits in place gives 12 into 4096, which is 49152, plus 3 into 256, which is 768, plus 11 into 16, which is 176, plus 1, and the four terms add up to 50097. Options A and B are far too small, because any four-digit hexadecimal number beginning with C is at least 12 into 4096, that is 49152, so 12197 and 32097 cannot be right. Option C lies in the right range but would need the second digit to be about 11, not 3, since 52097 minus 49152 is 2945, which is about 11 sixteens of 256. Exam tip: fix the weights 4096, 256, 16 and 1 in mind, and remember A to F mean 10 to 15.