Basic components of a computer system

Correct answer: A. A hard disk provides long-term storage while RAM is temporary working memory

Explanation: A hard disk is non-volatile storage: it keeps files and programs even when electrical power is removed. RAM is volatile working memory used by currently running programs, so its contents are normally lost when the computer is switched off. Therefore option A is correct. Options B and D wrongly treat the devices as identical, while option C reverses their permanence characteristics.

Correct answer: A. Motherboard

Explanation: The governing concept is the role of a computer’s main circuit board. The motherboard provides the sockets, electrical pathways, and communication connections needed for the CPU and RAM to work with other components. Therefore, option A is correct. A mouse pad, printer tray, and speaker box are external accessories or enclosures and do not serve as the central connection board.

Correct answer: C. Keyboard

Explanation: The governing concept is the difference between input and output hardware. A keyboard has alphabetic, numeric and control keys that allow a user to send characters and commands to the computer, so option C is correct. A monitor displays results, speakers produce sound and a printer produces paper output; none of these is the normal device for entering letters and numbers.

Correct answer: A. Central processing unit

Explanation: The governing concept is the role of the central processing unit, or CPU. It interprets and executes instructions, performs calculations and coordinates many operations of the computer, which is why it is commonly called the brain of the computer. Option A is therefore correct. A mouse provides input, a monitor displays output and a speaker produces sound; these components do not perform the central processing role.

Correct answer: C. Monitor

Explanation: The governing concept is output hardware. A monitor receives processed signals from the computer and presents text, images, video and other information on its screen, so option C is correct. A keyboard and microphone send user input to the computer, while a scanner captures paper images or text as input. These distractors perform input functions rather than displaying computer information.

Correct answer: D. Scanner

Explanation: The governing concept is converting physical input into digital data. A scanner uses optical sensing to capture the text or image on a paper document and create a digital representation that can be stored or edited on a computer. Therefore, option D is correct. A printer produces paper output, a projector displays information on a surface and a speaker produces audio, so none of them digitises paper.

Correct answer: A. Microphone

Explanation: The governing concept is input and output devices. A microphone captures voice and converts sound waves into electrical or digital signals that the computer can store or process, so option A is correct. A webcam mainly captures pictures or video, a speaker sends sound out from the computer, and a scanner captures printed images or text. Therefore, the microphone is the appropriate voice-recording device.

Correct answer: B. Webcam

Explanation: The governing concept is visual input. A webcam uses a camera sensor to capture a person’s image or live video and sends that visual data to the computer for transmission during a video call, so option B is correct. A printer produces paper output, a speaker provides sound output, and a pen drive stores or transfers files; none of these captures the caller’s image.

Correct answer: C. Projector

Explanation: The governing concept is computer output. A projector receives visual signals from a computer and enlarges the image onto a wall or screen, making option C correct for presentations and classroom displays. A mouse sends control input, a modem handles network communication, and a scanner converts paper material into digital input. These devices do not project computer content onto a large surface.

Correct answer: D. Pen drive

Explanation: The governing concept is portable secondary storage and file transfer. A pen drive stores copied files in flash memory and can be removed from one computer and connected through a USB port to another, so option D is correct. A monitor displays information, a mouse supplies user input, and a speaker produces audio output; none is designed to carry stored files between computers.

Correct answer: A. Network interface card

Explanation: The governing concept is the role of communication hardware in networking. A Network Interface Card, or NIC, provides the computer with a network connection and commonly includes an Ethernet port or equivalent wired interface. Thus, option A is correct. A sound card processes audio, a graphics card handles images and display output, and a webcam captures video; none of these is designed to provide a wired local-network connection.

Correct answer: C. Arithmetic and logic unit

Explanation: The arithmetic and logic unit, or ALU, is the CPU component responsible for arithmetic operations such as addition and subtraction and logical operations such as comparison, AND, and OR. Therefore, option C is correct. The control unit directs instruction execution, the power supply provides electrical energy, and the display unit presents output; none performs the stated calculations as its main role.

Correct answer: C. Cooling fan and heat sink

Explanation: The governing concept is heat management in computer hardware. A cooling fan moves hot air away, while a heat sink absorbs and spreads heat from components such as the processor so it can be released more effectively. Therefore, option C is correct. A mouse, webcam, and scanner are input devices and do not cool the processor or control internal temperature.

Correct answer: D. No default application is associated with that file type

Explanation: The governing concept is file-type association. Operating systems use a file extension or type to identify which application should open a file. If no default association exists, the system cannot choose automatically and displays an application-selection prompt. Hence, option D is correct. Excess memory, mouse speed, and monitor colour do not determine which program handles a file type.

Correct answer: A. Converting electrical power into voltages suitable for components

Explanation: The power supply unit, or PSU, receives electrical power from the mains and converts it into regulated voltage levels needed by the motherboard, processor, storage devices, and other components. Therefore, option A is correct. File compression belongs to software, writing processor instructions is a programming task, and creating passwords is an operating-system or user-security function, not a PSU function.

Correct answer: B. Mathematical calculations and logical comparisons

Explanation: The governing concept is the Arithmetic and Logic Unit, or ALU, a processing component of the CPU. It performs arithmetic operations such as addition and subtraction and logical operations such as comparing values or testing conditions. Hence, option B is correct. Saving files is mainly a storage or operating-system activity, displaying pictures is an output function, and connecting cables is a physical networking task.

Correct answer: C. The original file generally remains safe

Explanation: A shortcut is a separate link that points to an item stored elsewhere; it is not the original file itself. Deleting the shortcut normally removes only that pointer, so the original file remains in its actual folder with the same contents and format. The original is affected only if the user separately deletes or modifies it. Therefore, option C is correct; the other choices describe effects that do not follow from deleting a shortcut.

Correct answer: A. Hardware

Explanation: Hardware is the governing concept for the physical parts of a computer system. Components such as the keyboard, monitor, motherboard, and hard disk occupy physical space and can be touched, so option A is correct. Software consists of programs and instructions, while data and information are digital content processed or produced by the system; none of these is a physical component itself.

Correct answer: B. Central Processing Unit

Explanation: The governing concept is the role of the CPU in the computer system. The Central Processing Unit fetches, interprets, and executes instructions and coordinates many processing operations, so it is commonly called the brain of the computer. Option B is therefore correct. A monitor displays output, a mouse sends pointing input, and a printer produces paper output; none performs the central processing role.

Correct answer: D. Monitor

Explanation: The governing concept is input and output classification. A monitor receives the processed signal from the computer and presents text, images, or video on a screen, so option D is correct. A scanner captures physical documents, a microphone captures sound, and a mouse sends pointing commands; these are input devices rather than devices that display computer results.

Correct answer: A. Pointing input device

Explanation: The governing concept is device classification by function. A mouse sends the user’s movements, clicks, and selections to the computer and controls the on-screen pointer, so it is a pointing input device and option A is correct. It does not display results like an output device, preserve files like storage, or execute instructions like a processor. Its main role is user input and navigation.

Correct answer: C. Microphone

Explanation: The governing concept is audio input. A microphone detects sound waves and converts them into an electrical or digital signal that the computer can record, process, or use in communication, so option C is correct. A speaker does the opposite by producing sound from computer output. A printer creates paper output and a monitor displays visual output; neither enters sound into the computer.

Correct answer: D. Speaker

Explanation: The governing concept is audio output. A speaker converts the computer’s audio signal into vibrations in the air, allowing the user to hear music, speech, or alerts; therefore option D is correct. A keyboard and mouse send commands as input, while a scanner captures images or documents. Those devices provide information to the computer rather than producing audible output for the user.

Correct answer: A. Printer

Explanation: The governing concept is hard-copy output. A printer receives digital text or images and transfers them onto paper, producing a physical copy; therefore option A is correct. A scanner performs the reverse direction by converting a paper document into digital data. A mouse supplies pointing input, and a microphone supplies audio input, so neither creates a paper copy of digital content.

Correct answer: B. RAM

Explanation: The governing concept is primary, volatile memory. RAM temporarily holds the instructions and data currently needed by the CPU, allowing active programs to run quickly; therefore option B is correct. Because RAM is volatile, its contents normally disappear when power is removed. A hard disk, pen drive, and optical disc are secondary storage media intended to retain data for longer periods.