Basic components of a computer system

The governing concept is computer memory and storage. The memory and storage unit holds data and instructions for immediate processing or later use. Primary memory, such as RAM, is usually temporary, while secondary storage, such as a drive, retains information more permanently; together they explain option A. The control, input, and output units perform different roles and do not primarily store all data and instructions.

The governing concept is the distinction between internal components and peripherals. A peripheral device is hardware connected to a computer but positioned outside the main system unit, such as a keyboard, mouse, monitor, printer, or scanner. Thus option B is correct. A kernel is core operating-system software, a register is tiny CPU storage, and firmware is embedded control software rather than an external device.

The governing concept is the distinction between a computer’s internal unit and its external peripheral devices. The system unit is the main enclosure that houses the motherboard, processor, memory, power supply, and usually storage drives. A monitor displays output, a keyboard provides text input, and a scanner captures images or documents; none of these normally contains the computer’s internal processing hardware. Therefore, option C is correct. The system unit should not be confused with the CPU alone.

The governing concept is that different computer components perform separate functions. The monitor is an output device that presents visual information, whereas the system unit contains the processor and other internal hardware. If the monitor is switched off, the system unit can still run programs or process data, although the user cannot see the visual result. Switching it off does not erase data or damage the processor, and a keyboard remains an input device. Thus, option A is correct.

The governing concept is targeted hardware troubleshooting: begin with the component directly responsible for the failed function. Sound output depends first on speakers or headphones, their power and volume, and the audio cable or connection; software mute settings may then be checked. A hard disk, scanner, printer, processor, or mouse does not normally produce the missing audio. Therefore, option C is the best first check because it identifies the relevant output hardware and its connections.

The governing concept is matching input devices to the type of information being captured. A webcam captures the student’s moving or still video and sends it as visual input, while a microphone captures voice as audio input. A speaker only produces sound, a printer produces paper output, a scanner captures documents, and a hard disk stores data. Therefore, option A contains the two required input components for sending video and voice in an online class.

The governing concept is the functional organization of a computer system. Input units accept data, the processing unit performs operations, storage keeps programs or results, and output units present the processed information. These parts work together rather than existing as an isolated software list, network, or storage medium. Their coordinated arrangement provides the complete data-processing cycle. Therefore, option B is correct because all four functional categories together describe a complete computer system.

The governing concept is the motherboard’s role as the main circuit board that connects and supports the computer’s internal components. It contains a processor socket designed for a compatible Central Processing Unit, along with memory slots and other expansion connections. A power supply provides electrical power but does not hold the CPU; a printer and scanner are external peripheral devices. Therefore, option B is correct because the CPU is installed directly into the appropriate socket on the motherboard.

The governing concept is the motherboard’s role as the main circuit board of a computer. It provides electrical connections and communication pathways among the CPU, memory, storage devices, expansion cards, and other internal parts. Therefore, option A is correct. A monitor, printer, and webcam are mainly external input or output devices; they do not connect the principal internal components to one another.

The governing concept is physical placement of the processor on the motherboard. The CPU is fitted into a specially designed processor socket, whose contacts match the processor pins or pads and allow communication with the board. Thus option B is correct. A RAM slot holds memory modules, an expansion slot accepts cards such as graphics or network cards, and a power port supplies electricity rather than holding the CPU.

The governing concept is motherboard memory installation. A RAM module is inserted into a dedicated memory slot, commonly called a DIMM slot in desktop computers. Consequently, option C is correct. The processor socket is designed for the CPU, while USB and audio ports are external connection points for peripherals. The long DIMM slots use aligned contacts and retaining clips to hold the memory module securely.

The governing concept is power distribution inside a computer. The power supply unit, or PSU, receives electrical power from the wall and converts it into suitable regulated voltages for the motherboard, processor, drives, and other components. Therefore, option A is correct. A graphics card processes images, a network card handles network communication, and a sound card handles audio; none is responsible for supplying power to the whole system.

The governing concept is active cooling through airflow. A cooling fan rotates its blades to move air through the computer cabinet, helping bring cooler air toward heat-producing parts and carry warm air away. Therefore, option C is correct. A sound card processes audio, while a scanner and keyboard are external input devices; none of these components circulates air. Good airflow helps prevent overheating and supports stable computer operation.

The governing concept is audio input and output. A sound card, also called an audio card, processes signals received from a microphone and sends audio signals to speakers or headphones, supporting recording and playback. Therefore, option A is correct. A router directs network traffic, the motherboard battery maintains settings such as the real-time clock, and a hard disk stores data. These components do not primarily handle sound.

The governing concept is network connectivity through a hardware interface. A network interface card, or NIC, provides the computer’s connection to a wired local network, usually through an Ethernet port and cable. Hence option B is correct. A graphics card handles visual output, a sound card handles audio, and a memory card is removable storage rather than a network adapter. The NIC also helps exchange data using network communication protocols.

The correct answer is the hard disk drive because it records data magnetically on one or more rotating platters. A read/write head moves over the platter surface to access the data. An SSD, pen drive, and memory card use flash memory with no rotating magnetic disks. Therefore, the device specifically identified by rotating magnetic platters is the HDD.

A solid state drive is the correct answer because it stores data electronically in flash-memory chips and has no spinning platters, moving heads, or other mechanical parts. HDDs and floppy drives depend on rotating magnetic media, while an optical drive uses a rotating disc and a moving laser assembly. The absence of mechanical movement is the defining feature of an SSD.

CDs and DVDs are optical media because a laser reads the pattern of pits and lands on their surfaces; recordable versions also use laser light to write data. Magnetic media, such as hard disks and tapes, use magnetised areas instead. Flash drives and memory cards are solid-state storage, while primary memory refers mainly to RAM and related working memory, not removable optical discs.

A card reader is designed to accept a memory card and transfer its stored data to a computer or another compatible device. It may also allow files to be written back to the card, depending on the model. A printer cartridge holds ink or toner, a sound card processes audio signals, and a heat sink removes heat. None of those devices is intended to read memory-card data.

The USB port is the best general answer because Universal Serial Bus is designed to connect computers with many digital peripherals, including keyboards, mice, printers, cameras, and storage devices. An audio port is mainly intended for sound signals, a video port for display signals, and a power socket supplies electricity rather than carrying ordinary peripheral data. Thus option D is the broadest and most suitable choice.

HDMI is the correct choice because it carries a digital video signal from a computer or other source to a monitor or television. Modern HDMI connections can also carry digital audio through the same cable. A microphone port accepts sound input, a network port transfers network data, and a power port supplies electricity. These alternatives do not primarily provide a digital display signal, so option A is unambiguous.

A wired network cable, commonly called a LAN cable or Ethernet cable, is connected to an Ethernet port, usually through an RJ-45 connector. This port allows a computer to communicate with a router, switch, or other network device. USB connects general peripherals, HDMI carries display signals, and an audio port handles sound. Therefore option B correctly identifies the network connection port.

A touchscreen performs both output and input functions. Its display produces visual output, while its touch-sensitive surface detects taps, swipes, and other commands as input. A basic printer mainly outputs printed information, speakers output sound, and a microphone mainly accepts sound input. Because the touchscreen combines display and touch detection in one device, option C is the only complete answer.

A multifunction printer generally combines printing, scanning, and copying in one device; many models may also support faxing or network connectivity. Printing produces a paper output, scanning converts a paper document into digital input, and copying reproduces a document. The other options describe only typing, video display, or networking, none of which represents the printer’s main combined functions. Therefore option D is correct.

A trackball is a pointing input device. It contains a ball that the user rolls with the fingers or palm to move the on-screen pointer, and buttons can be used to select items. A speaker produces sound, a printer creates printed output, and a microphone captures audio input. Those devices do not control the pointer, so the trackball is the only correct option.