Computer Science Test 1 Nddc Scholarship

A tracker ball (or trackball) is an input device used to control the movement of a cursor on the screen, similar to a mouse. Plotters, speakers, and printers are all output devices because they receive data from the computer and convert it into a physical form, such as large-scale drawings, sound waves, or printed text.

The CPU consists of the Control Unit (CU), which directs the flow of data and manages the execution of instructions, and the Arithmetic Logic Unit (ALU), which performs all mathematical calculations and logical comparisons. Together, these units allow the processor to interpret software commands and manipulate data according to the program's requirements.

A computer cannot function without both parts. Hardware refers to the tangible, physical components like the motherboard, CPU, and monitor. Software refers to the intangible set of instructions, such as the operating system and applications, that tell the hardware what to do. The interaction between these two components is what defines the functionality of a computer system.

A bar code reader (or scanner) emits a laser or LED light onto a printed barcode. The black lines absorb the light while the white spaces reflect it. The device's sensor detects these varying reflections and converts them into digital signals, allowing the computer to instantly identify products, track inventory, or process sales transactions with high accuracy.

Software is a generic term for organized collections of computer data and instructions. It is typically broken down into system software (like Windows or Linux) and application software (like Word or Chrome). While software can be stored on physical media like CDs, the term specifically refers to the logic and code that drives the hardware's operations.

ROM stands for Read-Only Memory. It is 'non-volatile,' meaning it retains its data even when the computer is turned off. ROM is used to store essential firmware, such as the BIOS, which contains the start-up instructions the computer needs to boot up. In contrast, RAM is volatile and is wiped clean every time the system loses power.

The Universal Serial Bus (USB) replaced older, slower technologies like serial and parallel ports as the standard for connecting printers. USB offers much higher data transfer speeds, supports 'Plug and Play' functionality, and allows multiple devices to be connected to a single computer easily, making it the most modern choice listed.

The defining advantage of a laptop is its portability. Unlike a desktop, a laptop combines the processor, monitor, and keyboard into a single, battery-powered unit. This allows users to maintain productivity while traveling, in meetings, or working remotely, effectively bringing the full power of a computer to any location.

Main memory, or Random Access Memory (RAM), is actually 'volatile' memory. This means it requires a constant flow of electricity to maintain the data stored within it. As soon as the computer is turned off or loses power, all information currently held in the RAM is instantly erased, which is why saving work to a hard drive is essential.

A scanner works by using light-sensing hardware to 'read' a physical document or photograph. It captures the reflected light and converts it into a digital format that the computer can store as an image or a PDF file. This process is essentially the reverse of what a printer does.