Basic components of a computer system

The governing concept is volatility and the purpose of primary memory. RAM is volatile working memory: its contents normally disappear when power is removed, although it supports active programs and data. ROM is non-volatile and can retain essential instructions without continuous power. Therefore, option D is correct. The other choices wrongly classify both memories as permanent or input devices, or restrict RAM to sound.

The governing concept is the motherboard’s role as the central hardware platform. It provides sockets, slots, buses and communication pathways that allow the processor, RAM, storage interfaces and other components to connect and exchange signals. Thus, option A is correct. A display is produced by a monitor or graphics hardware, internet access needs network hardware and software, and printing is performed by a printer.

The governing concept is the memory hierarchy. Cache is a small, high-speed memory located close to or within the processor. It keeps frequently used instructions and data so the CPU can access them faster than retrieving them repeatedly from slower main memory. Therefore, option B is correct. Cache is not a permanent file store, printer, or networking device; those choices describe different hardware functions.

The governing concept is the CPU register as the smallest and fastest working storage. Registers hold a very small amount of immediate data, addresses or instruction information that the processor is currently using. This minimizes access time during instruction execution, so option C is correct. Large video storage belongs to storage drives, power comes from the power supply, and paper documents are produced through output devices.

The governing concept is the difference between electronic flash storage and magnetic mechanical storage. An SSD stores data in flash memory and has no spinning platters or moving read-write heads, so it usually accesses data more quickly and with lower mechanical delay than an HDD. Therefore, option D is correct. SSDs still need power, can store many file types, and are storage devices rather than parts of RAM.

The governing concept is power conversion and distribution in computer hardware. A Power Supply Unit converts incoming electrical power into suitable regulated forms and supplies them to the motherboard, processor, drives and other components. Thus, option A is correct. Organising files is an operating-system task, scanning is performed by an input device, and sound output is produced through audio hardware such as speakers.

The governing concept is thermal management in computer hardware. A cooling fan moves hot air away from components and helps maintain a safe operating temperature. If heat builds up, the processor and other parts may slow down, become unstable, or suffer damage. Therefore, option B is correct. Deleting files is a software function, internet speed depends on network equipment, and screen size is controlled by display settings, not the fan.

The governing concept is visual processing and output. A graphics card, also called a video card or GPU, processes image and video information and sends suitable signals to the monitor. Thus option C correctly describes its specific purpose. Sound recording belongs mainly to audio hardware, a network card manages network communication, and permanent file storage is handled by devices such as an SSD or hard disk.

The governing concept is audio input and output. A sound card converts digital audio into signals that speakers or headphones can play, and it can convert microphone signals into digital data for the computer. Therefore option D is correct. Cooling is performed by fans, copying files is an operating-system task, and displaying images is primarily handled by graphics hardware rather than a sound card.

The governing concept is computer networking. A network card, or network interface card, provides the hardware interface through which a computer sends and receives data over a wired or wireless network. Hence option A is correct. Printing requires a printer, scanning requires a scanner, and RAM is temporary working memory; none of those functions is the main purpose of a network card.

The governing concept is dual-function input and output. A touchscreen displays text, images, buttons, and other information, so it performs an output function. At the same time, its touch-sensitive layer detects a finger or stylus and sends that command to the computer, so it also performs an input function. Therefore option B is correct; it is not mainly a storage, sound-only, or electricity-generating device.

The governing concept is the direction of data flow between input and output devices. A printer receives digital text or images and produces a physical paper copy, so it is an output device. A scanner reads paper or photographs and converts them into digital data, so it is an input device. Therefore option C is correct. Option D reverses their functions, while A and B incorrectly classify both devices.

The governing concept is power protection and continuity. An Uninterruptible Power Supply, or UPS, uses stored electrical energy to provide short-term power when the main supply fails or fluctuates. This gives the user time to save work and shut the computer down safely, reducing data loss and hardware stress. Therefore option D is correct; a UPS does not increase RAM, internet speed, or automatically print files.

The governing concept is internal communication within a computer system. A computer bus is a set of shared pathways or connections that carries data, addresses, and control signals between components such as the processor, memory, and input-output devices. Therefore option A is correct. Holding paper is a printer function, screen brightness is a display setting, and naming files is managed by the operating system.

The governing concept is the division of roles among system buses. The data bus carries the actual values or instructions being transferred between the processor, memory, and other components for processing. Thus option B is correct. The address bus identifies the location involved, and the control bus carries timing or control signals; electrical power is supplied through power connections, not the data bus’s main role.

The governing concept is addressing in computer architecture. The address bus carries the location information that tells the processor which memory cell or input-output device should be read from or written to. Therefore option C is correct. The data bus carries the actual data, while image display, sound transmission, and file compression are application or peripheral functions rather than the address bus’s role.

The control bus carries command and timing signals that coordinate the activities of the CPU, memory and input-output devices. Read and write signals specify the required operation, while timing signals help components act in the correct sequence. Therefore, option D is correct. Images, file names and permanent data are not the characteristic signals carried by the control bus.

In the input-process-output cycle, the CPU performs the process stage. It receives data and instructions, interprets the instructions, carries out arithmetic or logical operations, and helps produce the required output. Thus, option A correctly describes its role. Printing is an output function, supplying electricity belongs to the power system, and scanning is an input function.

The keyboard is successfully providing input, but the expected visual output is missing. The monitor, its cable, display power and related visual output settings should therefore be checked first. Option B is correct because it directly matches the symptom. A hard disk stores data, a printer tray handles paper, and a cooling fan controls temperature; none normally displays typed characters.

If headphones produce sound, the computer, audio processing and much of the sound output path are working. The fault is therefore most likely in the speakers themselves, their cable, power switch or connection. Option C is correct. The processor and hard disk do not directly produce speaker sound, and the keyboard is unrelated to this output symptom.

A shutdown shortly after startup can occur when the power supply is unstable or when the processor becomes too hot and protective circuitry turns the computer off. The power supply, cooling fan, heat sink and ventilation should therefore be checked. Option D is correct. The other device pairs are peripheral equipment and do not normally cause this characteristic system-wide shutdown.

An input device first sends entered data into the computer system, where the processing unit, especially the CPU with associated memory, receives and interprets it for processing. Therefore, option C is the best answer. A printer, monitor and speaker are output devices; they present results rather than accept input data for computation.

The system unit is the main computer case and contains several internal components, such as the motherboard, CPU, RAM, storage and power supply. The CPU is only the processing component installed inside that unit. Thus, option D is correct. The system unit is not merely software or a monitor, and the CPU is not normally an external peripheral device.

An external hard disk is housed separately from the computer and connects through an interface such as USB, so it can be moved between compatible systems and used for backup or file transfer. Option A is correct. It is a storage device, not only an input device; it does store data, and it is not always faster than RAM, which serves a different memory function.

The governing concept is the difference between a hardware device and a storage medium. An optical drive is the mechanism that uses a laser to read data from, or sometimes write data to, a CD, DVD, or similar disc. The optical disc itself stores the information. Therefore, option B is correct; option A confuses the device with the medium, while C and D describe unrelated functions.