Basic components of a computer system

The address bus identifies where a transfer should occur, and the data bus carries the actual information. The control bus supplies signals such as read, write, interrupt, and timing signals that tell devices what operation to perform and when. Without these coordinating signals, an address and data value would not form a properly controlled transaction. It is not primarily a storage, display, or power bus.

Read Only Memory traditionally stores firmware or boot instructions that help initialize hardware and begin the startup process. If those instructions are corrupted, the processor may be unable to complete the power-on self-test or locate the next stage of the boot process. The computer may therefore fail to start properly. Such corruption does not directly resize a mouse, increase printer-paper use, or switch off a speaker.

Cache memory is small but usually much faster for the processor to access than main memory. It stores frequently used instructions and data, or information likely to be needed soon, close to the CPU. This reduces repeated waits for slower RAM and can improve processing speed. Cache is not a complete file-backup system, a network connector, or a printer-ink-saving device.

A processor produces heat while it switches and performs calculations, so a cooling fan helps remove that heat. If the fan stops, the temperature can rise beyond the safe operating range. Modern systems may reduce processor speed through thermal throttling or shut down automatically to prevent damage. The failure does not rename files, alter keyboard language, or increase hard-disk capacity.

A graphics card requires sufficient wattage and stable voltage from the Power Supply Unit. If the PSU cannot provide the needed power, the computer may fail to boot, crash under graphics load, restart unexpectedly, or behave unstably. The issue concerns electrical capacity and system operation; it does not automatically enlarge the mouse pointer, compress all files, or change the monitor language.

The graphics card processes or supplies the video signal sent to the display. If it fails while other components remain active, the monitor may show no picture, a blank screen, incorrect colours, lines, or distorted images. Sound recording is normally associated with the microphone and audio hardware, while a graphics-card failure cannot enlarge a pen drive or remove physical keyboard keys.

When the sound card is known to work but recording fails, troubleshooting should begin with the signal path specific to the microphone. Check that the microphone is connected to the correct input, powered if required, unmuted, selected as the active recording device, and given permission in the operating system. Hard-disk capacity, monitor resolution, and the printer queue do not normally control microphone input.

The governing concept is that different network media require suitable hardware interfaces. A wired connection can work through Ethernet hardware, but detecting Wi-Fi networks requires a wireless network adapter, together with its driver and antenna. Therefore, option B is correct. An optical drive reads discs, a sound card handles audio, and a printer driver supports printing; none of these scans for wireless networks.

The governing concept is that RAM must make a reliable electrical connection with the motherboard before the system can use it. If the module is loose or inserted incorrectly, the firmware may fail to detect the memory, and the computer may show an error or fail during startup. Option A is correct. Printer speed, monitor size, and cloud movement are unrelated to RAM seating.

The governing concept is the effect of mechanical design on storage durability. An SSD stores data in flash memory and has no spinning platters or moving read/write heads, so physical shocks generally pose less mechanical risk than they do for a traditional hard disk. Option A is correct. An SSD still needs power, does not replace the CPU, and normally stores data persistently rather than only temporarily.

The governing concept is preventive data protection during possible hardware failure. Unusual clicking, grinding, or repeated seeking sounds can indicate a problem with the disk’s mechanical parts. The safest response is to copy important files to a reliable backup location without unnecessary use, then seek qualified inspection or replacement. Option A is correct; shaking, deleting files, or changing brightness cannot repair the disk and may worsen data loss.

A monitor needs electrical power and a separate video signal from the computer. Therefore, its power light can be on even when the display cable is loose, the wrong input is selected, or the computer is not sending output. Option A is correct because it directly describes the missing video signal. Printer ink, RAM capacity, and speaker status do not normally cause a monitor’s “no signal” warning.

Because the projector shows the image, the computer is producing usable visual output and the source content is available. The fault is therefore more likely in the monitor, its cable, its selected input, or its connection. Option B is correct. The processor cannot be declared faulty, and the evidence does not prove that software or the hard disk has been deleted or damaged.

A touchscreen combines an output display with an input-sensing layer. Since the image appears correctly, the display-output function and basic power are working. The failure is more likely in the touch sensor, its controller, calibration, or the device driver. Option B is correct. Storage and the power supply are not the best conclusions, while option A ignores the separate input function.

Reading the barcode successfully shows that the scanner is capturing and transmitting the code. If the displayed product is wrong, the system may be matching that code with an incorrect record, such as a mistaken database entry or product-code mapping. Option A is correct. Monitor power, the scanner’s colour, and the computer fan do not determine which product record is selected.

Paper feeding shows that the printer’s paper-handling mechanism is operating. Blank output instead points first to the printing material or delivery system: an empty cartridge, dried ink, low toner, a blocked print head, or a related setting. Option A is the most reasonable first check. A mouse button, network card, or computer case does not directly create blank printed pages once a print job is received.

A clear scanned image indicates that the scanner, lighting, and basic image-capture path are functioning sufficiently. The error occurs when optical character recognition interprets the image, so the OCR engine, selected language, document quality, or recognition settings should be checked. Option B is correct. The monitor stand and general power supply do not explain incorrect characters when a clear image is already produced.

A webcam and a microphone are separate input devices with different data paths. Working video confirms that the visual-input path is functioning, while missing microphone audio points to the audio-input path, its mute setting, connection, permission, or driver. Option B is correct. Permanent storage and printing are not required for capturing live microphone sound, and option A contradicts the working video evidence.

Headphones and speakers receive audio from the same general sound-output system, so clear headphone sound suggests that the sound card and basic processing are probably working. The fault is more likely in the speakers, their cable, jack, volume level, or physical condition. Option A is correct. A hard disk, RAM, or keyboard would not normally produce distortion only from the speakers.

A UPS supplies temporary power during an outage by switching to its internal battery. If it turns off immediately, the battery may be discharged, aged, damaged, or unable to support the connected load; a battery connection or UPS fault is also possible. Option A is the best answer. RAM quantity, monitor resolution, and an empty print queue do not provide backup energy or control this switching function.

When the computer shows no response at all, troubleshooting should begin with the power path: check the wall supply or switch, power cable, connections, and then the power supply unit. This proceeds from simple external causes to the internal component. Option A is correct. Applications, wallpaper, folders, webcam, and speakers cannot be checked meaningfully before the computer receives power and starts.

The small motherboard battery, commonly called the CMOS or real-time-clock battery, supplies a tiny amount of power when the computer is switched off. It helps preserve the system clock and selected firmware settings. Therefore, option A is correct. It does not power the processor, operate a printer, or create file backups; those functions require other hardware or software.

Dust can cover fan blades, heat sinks, and ventilation openings. These block or reduce airflow, so heat is removed less effectively and internal temperatures may rise. Consequently, the computer may slow down, become unstable, or suffer hardware damage. Option A correctly states both linked effects. Dust cannot make RAM permanent, shorten file names, or improve printer speed.

Installed RAM and usable RAM are not always identical. The motherboard, firmware, memory architecture, or operating-system edition may impose a maximum addressable amount. A reserved portion may also be used for hardware. Thus option A is correct. Speaker volume, scanner cleanliness, and printer paper do not determine how much system memory the operating system can address.

Clock speed indicates how many processor cycles can occur per second, but it is only one performance factor. A task may wait for RAM or storage, depend on software efficiency, use several cores, or require graphics processing. Therefore option A is correct. The processor does perform calculations, and clock speed is not a printer or monitor function.