Basic components of a computer system

Correct answer: A. To connect a RAM module to the motherboard

Explanation: A memory slot is a connector on the motherboard designed to hold a RAM module. RAM provides temporary working storage for data and instructions that the processor is currently using. Therefore, option A is correct. Mounting a monitor, holding printer paper and recording sound are unrelated tasks performed by other equipment or mechanisms, not by a motherboard memory slot.

Correct answer: B. Adding extra cards such as graphics or network cards

Explanation: An expansion slot is a connector on the motherboard that permits an additional expansion card to be installed. Such cards can add or improve capabilities, for example graphics, sound or network communication. Option B is correct. File compression is software-based, scanning is done by a scanner, and shutting down is an operating-system or power-control action rather than the purpose of a slot.

Correct answer: C. It displays computer visuals on a large surface

Explanation: The governing concept is that an output device presents processed information to a user. A projector receives visual signals from the computer and enlarges the resulting text, images, or video onto a wall or screen. Thus, option C correctly describes its function. Typing and recording are input activities, whereas permanent file storage belongs to storage devices, not a projector.

Correct answer: D. Providing image and audio input during a video call

Explanation: The governing concept is combined input from different devices. A webcam captures the user’s video, while a microphone captures the user’s voice; communication software then sends these inputs during a video call. Therefore, option D is correct. Storage, printing, and cooling are performed by storage hardware, printers, and cooling components rather than by these two input devices.

Correct answer: C. Both control the screen pointer

Explanation: The governing concept is pointing input. A mouse detects movement on a surface, while a touchpad detects finger movement on a touch-sensitive panel; both translate that movement into pointer movement on the screen. Therefore, option C is correct. Neither device is primarily a sound output device, storage device, or printer, so A, B, and D are incorrect.

Correct answer: D. Operating without a direct power connection

Explanation: The governing concept is the role of a power source. A laptop battery stores electrical energy and allows the computer to operate when it is not connected directly to an electrical outlet. If the battery fails, portability and battery-powered operation are lost, so option D is correct. Displaying colours, renaming files, and recording sound depend mainly on other hardware and software functions.

Correct answer: A. Supporting and physically protecting internal components

Explanation: The governing concept is physical organisation and protection of computer hardware. The case holds components such as the motherboard, power supply, storage drives, and cooling parts in a structured enclosure, protecting them from accidental contact and helping manage airflow. Therefore, option A is correct. Software creation, internet-data processing, and paper scanning are not the case’s primary functions.

Correct answer: B. To send visual signals to a monitor or projector

Explanation: The governing concept is matching a port to the type of signal it carries. A video port transmits visual output from a computer to a display device, such as a monitor, television, or projector. Thus, option B is correct. A microphone normally uses an audio connection, a pen drive uses a data port, and loading paper is a mechanical printer operation, so A, C, and D are unsuitable.

Correct answer: C. Microphone or headphones

Explanation: The governing concept is the function of ports according to the signal they carry. An audio port handles sound signals: a microphone sends sound into the computer, while headphones receive sound from it. Therefore, option C is correct. A hard disk and motherboard are internal hardware components, and a monitor stand is only a physical support, so none of those is an appropriate audio-port device.

Correct answer: D. It can connect many types of external devices

Explanation: The governing concept is a computer interface: a USB port provides a standard connection for exchanging data and, in many cases, supplying limited power. It can connect keyboards, mice, printers, cameras, storage drives and other compatible peripherals. Therefore, option D is correct. Options A and C are too narrow, while B describes no normal function of a USB port.

Correct answer: B. Keeping data, instructions and results

Explanation: The governing concept is computer storage. A storage unit holds data, programs or instructions, and results so they can be used later. Primary memory may hold working information temporarily, while secondary storage such as an SSD or hard drive can retain files for a longer period. Thus option B is correct. Playing sound and scanning images are device functions, whereas cooling is handled by fans or other cooling hardware.

Correct answer: C. The microphone is an input device and the speaker is an output device

Explanation: The governing concept is the direction of data flow. A microphone captures sound from the user and sends that audio into the computer, so it is an input device. A speaker receives processed audio signals from the computer and produces sound for the user, so it is an output device. Therefore option C is correct; the other choices reverse or misclassify the roles.

Correct answer: A. Central Processing Unit

Explanation: The governing concept is the role of the CPU in the fetch, decode, and execution cycle. The Central Processing Unit interprets program instructions and performs or controls the processing needed to produce results, so option A is correct. A monitor displays results, a keyboard supplies input, and a printer produces a paper output; none of these is the main instruction-processing unit.

Correct answer: B. Keyboard

Explanation: The governing concept is the distinction between input and output devices. A keyboard receives letters, numbers, and commands from the user and converts key presses into signals that the computer can process, so option B is correct. A monitor, speaker, and projector communicate processed information outward to the user, making them output devices rather than user-input devices.

Correct answer: C. Monitor

Explanation: The governing concept is output: information produced after processing must be communicated to the user. A monitor displays text, images, and other processed results on its screen, so option C is correct. A scanner, mouse, and microphone are input devices because they send images, movement commands, or sound into the computer rather than displaying its processed results.

Correct answer: A. Hard disk drive

Explanation: The governing concept is secondary, non-volatile storage. A hard disk drive stores operating-system files, applications, documents, pictures, and other data even after the computer is switched off, so option A is correct. The control unit manages instruction execution, a mouse is an input device, and cache memory is a small, fast temporary memory rather than a large permanent file store.

Correct answer: B. Solid state drive

Explanation: The governing concept is solid-state storage. A solid-state drive, or SSD, records data in flash-memory chips, so it has no spinning platters, read-write heads, or other moving mechanical parts; therefore option B is correct. A hard disk uses rotating magnetic platters, while optical discs and magnetic tape rely on different physical storage mechanisms.

Correct answer: C. Mouse

Explanation: The governing concept is pointing input. A mouse detects hand movement and converts it into movement of the on-screen pointer; its buttons also let the user click, select, drag, and open objects, making option C correct. A scanner captures images, a speaker produces sound, and a printer creates paper output, so none of those controls the pointer directly.

Correct answer: A. Microphone

Explanation: The governing concept is audio input. A microphone receives sound waves from a speaker and converts them into electrical or digital signals that the computer can record, process, or recognize, so option A is correct. Headphones are normally output devices, a monitor displays visual information, and a printer produces printed output rather than accepting voice.

Correct answer: B. Speaker

Explanation: The governing concept is audio output. A speaker converts the computer’s processed electrical or digital audio signal into vibrations in the air, allowing a person to hear sound; therefore option B is correct. A webcam captures video, a scanner captures printed images or text, and a mouse sends pointing commands, so they are input devices rather than sound-output devices.

Correct answer: D. Projector

Explanation: The governing concept is visual output on an enlarged display surface. A projector receives the computer’s video signal and enlarges the image by casting light onto a wall or screen, so option D is correct. A mouse supplies pointing input, a scanner captures physical documents, and a modem handles communication signals; none is designed primarily to show a large computer image.

Correct answer: A. Touchscreen

Explanation: The governing concept is a dual-function input-output device. A touchscreen displays text, images, and controls like a monitor, while its touch-sensitive surface detects a finger or stylus and sends the selected command to the computer; therefore option A is correct. A standard monitor usually only displays, a speaker produces sound, and a printer creates paper output.

Correct answer: B. Power supply unit

Explanation: The governing concept is power delivery in a computer system. The power supply unit, or PSU, receives electricity from the mains, converts it into suitable regulated voltages such as DC, and distributes power to the motherboard, processor, drives, and other components; therefore option B is correct. The motherboard connects parts, memory holds active data, and a hard disk stores files.

Correct answer: C. Input unit

Explanation: The governing concept is the input–process–output cycle. The input unit receives raw data and instructions from the user through devices such as a keyboard, mouse, scanner, or microphone. It is therefore the first receiving unit, making option C correct. The processing unit works on the data after entry, storage preserves it, and the output unit presents the processed result to the user.

Correct answer: D. Output unit

Explanation: The governing concept is the output stage of the input–process–output cycle. After the computer processes data, the output unit communicates the resulting information through a monitor, speaker, printer, or similar device. Hence option D is correct. Main memory temporarily holds working data, the control unit directs operations, and the input unit accepts data; none primarily presents the finished result to the user.