Basic components of a computer system

Correct answer: A. A slower component that limits overall system performance

Explanation: A bottleneck is the component or process whose limited speed or capacity restricts the performance of the whole system. For example, a slow disk can make a fast processor wait for data. Option A gives the correct meaning. The other choices describe power control, paper handling, or file renaming, none of which defines a performance bottleneck.

Correct answer: A. The hard disk

Explanation: The bottleneck is the component that limits the flow of work. Here, the hard disk supplies data more slowly than the processor can use it, so the processor remains idle while waiting. Therefore option A is correct. The monitor, keyboard, and speaker may participate in input or output, but none is identified as the limiting data-storage component in this situation.

Correct answer: A. The graphics card

Explanation: Rendering three-dimensional scenes requires substantial graphics processing, including calculations for shapes, textures, lighting, and frames. If RAM and storage are already adequate, the graphics card or graphics-processing capability may be the limiting component. Thus option A is the best answer. A microphone, barcode scanner, or printer does not normally render on-screen 3-D visuals.

Correct answer: A. The sound card, driver, and system resources

Explanation: Delayed or distorted audio can have several causes, so diagnosis should include the sound card, its driver, audio settings, and available system resources such as processor time and memory. Option A is correct because it combines the relevant hardware and software checks. A printer, scanner, monitor stand, mouse pad, or case colour cannot normally cause this audio-editing symptom.

Correct answer: A. The battery or charging circuit

Explanation: The governing concept is that a laptop has separate power and battery-charging paths. If it operates normally from the adapter, the processor, display and main power supply are probably receiving power. The fault is therefore most plausibly in the battery, charging circuit, charging connector or related control circuitry. A mouse, printer or optical drive cannot normally prevent battery charging, so option A is correct.

Correct answer: A. The touchpad may have a setting, driver or hardware problem

Explanation: The governing troubleshooting principle is to isolate the failed component by comparing related devices. Because an external mouse moves the pointer successfully, the operating system and general pointer processing are working. Attention should therefore move to the touchpad’s enable setting, driver, cable or hardware. A faulty processor, monitor or hard disk would not specifically explain a working external mouse, so option A is correct.

Correct answer: A. RAM

Explanation: The governing concept is volatility in the memory hierarchy. RAM temporarily holds the operating system’s active instructions and the data currently being worked on, but it requires continuous electrical power. When power is removed, its contents normally disappear. SSDs, hard disks and optical discs are non-volatile storage devices, so saved information can remain without power. Therefore option A correctly identifies the component showing this behaviour.

Correct answer: A. Motherboard, power and software compatibility

Explanation: The governing concept is system compatibility before installation. A replacement must fit the motherboard’s socket or interface, receive suitable voltage and power, and be supported by the operating system or required drivers. Ignoring any of these checks can cause failure, instability or even damage. Case colour, mouse-pad size and wallpaper have no technical role in component operation. Therefore option A is the only meaningful and complete pre-replacement check.

Correct answer: A. Input provides data, the processor processes it, memory stores it and output presents the result

Explanation: The governing concept is coordinated computer architecture and the input-process-storage-output cycle. Input devices supply data, the processor interprets instructions and performs operations, memory holds instructions or data temporarily or permanently, and output devices communicate results. No single component independently performs every function, and hardware needs software instructions to be useful. Consequently, option A gives the most complete and accurate relationship.

Correct answer: A. The computer may fail to start or produce beep signals

Explanation: The governing concept is the startup hardware check, often called POST. Before the operating system loads, the computer tests essential parts such as memory. If a RAM module is loose or not making proper contact, the system may fail to boot, show no display or communicate an error through beep signals. Printer ink, monitor dimensions and mouse speed are unrelated symptoms, so option A is correct. Power should be disconnected before reseating hardware.

Correct answer: B. Maintain the clock and firmware settings when power is off

Explanation: The governing concept is backup power for motherboard real-time clock and firmware configuration. The coin-cell battery supplies a very small current when the computer is switched off, allowing the system clock and selected BIOS or UEFI settings to persist. It does not provide the main power needed by the CPU, control monitor brightness or increase disk capacity. Therefore option B correctly states its principal function.

Correct answer: C. Carry data between computer components

Explanation: The governing concept is computer-bus communication. A data bus is a group of electrical pathways that carries actual data between the processor, memory, and input-output devices. It does not provide power, cool hardware, or print results. Therefore, option C is correct because it directly describes the movement of data among computer components; address and control buses perform different supporting functions.

Correct answer: D. Motherboard coin-cell battery

Explanation: The governing concept is retention of real-time-clock settings. The motherboard coin-cell battery supplies a small current while the computer is switched off, allowing the clock and related firmware settings to remain stored. If it becomes weak, the time repeatedly resets after startup. Graphics, sound, and network cards do not normally preserve the system clock, so option D is correct.

Correct answer: A. Central Processing Unit

Explanation: The governing concept is the CPU instruction cycle: fetch, decode, and execute. The Central Processing Unit obtains an instruction from memory, interprets what operation is required, and carries it out, using components such as the control unit and ALU. A monitor displays output, a scanner captures input, and a printer produces hard copy. Thus option A is correct.

Correct answer: B. Control Unit

Explanation: The governing concept is division of work inside the CPU. The Control Unit interprets instructions, sends control signals, and coordinates the ALU, registers, memory, and input-output operations in the proper order. The ALU calculates, registers hold very small immediate values, and cache supplies frequently used data quickly. Therefore, option B correctly identifies the coordinating part.

Correct answer: C. Arithmetic and Logic Unit

Explanation: The governing concept is the role of the Arithmetic and Logic Unit, or ALU. It performs arithmetic operations such as addition and subtraction and logical operations such as comparing whether values are equal, greater, or smaller. The Control Unit directs activities, memory stores instructions and data, and the output unit presents results. Hence option C is the only suitable answer.

Correct answer: D. Registers

Explanation: The governing concept is the processor memory hierarchy. Registers are tiny storage locations built into the CPU, so they can hold operands, instructions, or intermediate results needed immediately and provide the fastest direct access. Main memory is slower and larger, a hard disk is much slower secondary storage, and ROM is intended for retained instructions. Therefore, option D is correct.

Correct answer: A. By keeping frequently needed data close to the processor

Explanation: The governing concept is locality and the memory hierarchy. Cache is a small, high-speed memory located close to the processor. It keeps frequently used instructions and data so the CPU can retrieve them faster than from main memory, reducing waiting time during repeated work. It does not delete files or control display brightness or printer speed. Thus option A is correct.

Correct answer: B. There is not enough temporary space for active programs

Explanation: The governing concept is RAM capacity and multitasking. Main memory temporarily holds the operating system, active programs, and their working data. When many programs exceed available RAM, the system must move some information to slower storage or repeatedly manage memory, increasing waiting time and reducing responsiveness. The processor does not permanently shut down, and the other options are unrelated. Therefore, option B is correct.

Correct answer: D. Read-only memory

Explanation: The governing concept is non-volatile firmware storage. Permanent startup instructions, such as firmware used during the initial boot process, are generally stored in ROM or ROM-based memory so they remain available even when power is removed. Cache and main memory are used for fast or active working data, while virtual memory uses storage to extend RAM temporarily. Therefore, option D is correct.

Correct answer: B. To install additional graphics, sound, or network cards

Explanation: An expansion slot is a socket on the motherboard designed to accept an add-on card. A compatible graphics, sound, network, or other adapter can be inserted to add or improve a computer function. Thus, option B is correct. Expansion slots do not erase memory, adjust the physical height of a monitor, or compress files; those actions belong to software or external equipment.

Correct answer: B. It has no moving mechanical parts

Explanation: An SSD stores data in flash memory and accesses electronic memory cells without moving a read/write head or spinning a disk. This removes mechanical seek and rotational delay, so normal access is generally faster and quieter than in an HDD. Option B is correct. An SSD stores permanent data, does not require paper, and may be installed inside a computer rather than a monitor; those facts do not explain its speed.

Correct answer: A. Data Bus

Explanation: The data bus carries the actual binary values being transferred between the processor, memory, and other components. For example, when the processor reads a stored number, the address bus identifies the location, the control bus indicates a read operation, and the data bus carries the number itself. Therefore, the data bus is the correct answer. Address and control buses perform different supporting functions.

Correct answer: B. Address Bus

Explanation: The address bus carries the binary address that identifies a particular memory location or input-output location. The processor places the required location on this bus before a read or write operation. The data bus then carries the value, while the control bus carries signals such as read or write. An audio bus is not the standard bus used for memory addressing. Hence, option B is correct.

Correct answer: C. Control Bus

Explanation: The control bus carries command and timing signals that coordinate operations among the processor, memory, and peripheral controllers. Signals such as read, write, interrupt, and clock-related coordination tell components what action to perform and when. The data bus carries values, and the address bus identifies locations; neither one primarily carries commands. A video bus is not the general control pathway. Therefore, option C is correct.