Computer Science

A standalone computer requires RAM, a hard drive, and an operating system to function properly. A LAN card is not necessary for basic operation as it is used for network connectivity, which is optional for standalone use.

A hub is a network device that broadcasts incoming data packets to all connected devices and operates at the Physical Layer (Layer 1) of the OSI model. Switches, routers, and gateways operate at higher layers and do not broadcast to all devices indiscriminately.

The Presentation Layer (Layer 6) of the OSI Model is responsible for data translation, encryption, and decryption, ensuring that data is presented in a readable format for the application layer.

The Network Layer (Layer 3) of the OSI model is responsible for logical addressing, routing packets across networks, and controlling traffic to ensure data reaches its destination efficiently. This distinguishes it from other layers like the Data Link Layer, which handles physical addressing and local delivery.

A Network Interface Card (NIC) operates at the Data Link layer (Layer 2) of the OSI model, handling physical addressing and framing for data transmission over the network.

A gateway acts as a translator between different network protocols, enabling communication between networks that use different protocols. This is its primary function, distinguishing it from devices like routers or repeaters.

A Network Interface Card (NIC) provides the physical connection between a computer and a network, enabling the computer to communicate over the network. It does not route data or amplify signals, but rather facilitates data transmission at the physical and data link layers.

A router operates at the Network Layer (Layer 3) of the OSI model and forwards packets between different networks using IP addresses. Switches and bridges operate at the Data Link Layer, and hubs operate at the Physical Layer, so they do not perform routing based on IP addresses.

The Session Layer is responsible for establishing, managing, and terminating communication sessions between applications. It ensures that sessions are properly maintained and synchronized, which aligns with option A.

The Transport Layer is responsible for reliable data transmission, segmentation of data, and flow control between devices. It ensures that data is delivered error-free, in sequence, and without losses or duplications.

A repeater operates at the Physical Layer (Layer 1) of the OSI model and functions by amplifying or regenerating signals to extend the transmission distance of data. Routers, switches, and gateways operate at higher layers and perform different functions.

A bridge connects two or more network segments, dividing a network into segments and reducing collisions by filtering traffic based on MAC addresses. This improves network performance by limiting collision domains.

The Physical Layer (Layer 1) of the OSI model is responsible for the transmission and reception of raw bit streams over a physical medium, such as cables or wireless signals. It deals with the electrical, mechanical, and procedural interfaces to the physical medium.

LAN stands for Local Area Network, which refers to a network that connects computers within a limited area such as a home, school, or office building. The other options are incorrect expansions of the acronym LAN.

A computer network is defined as two or more connected computers that share resources such as files, printers, or internet connections. This distinguishes it from a single computer system, software programs, or databases.

LCD stands for Liquid Crystal Display, which is a common type of flat-panel display technology used in screens.

Data communication is the correct term for the transfer of data from one place to another. The other options refer to different processes: data processing involves manipulating data, data distribution is about sharing data but not necessarily transferring it between locations, and data encryption is about securing data.

Latency time, specifically rotational latency in disk drives, is the time it takes for the disk to spin so that the desired sector is under the read/write head. This matches option A, which correctly defines latency time as the time to spin data under the sector.

Bluetooth is a wireless technology specifically designed for exchanging data over short distances between electronic devices, making it the correct answer. Modem, Wi-Fi, and USB serve different purposes or operate over different ranges.

The default file extension for Notepad files is .txt, which stands for plain text files. Other options like .xls and .cdr correspond to Excel and CorelDRAW files respectively, so they are incorrect.

CRT (Cathode Ray Tube) technology is used in monitors to display images. It is not used in mice, CPUs, or Trojan horses.

Files with the 'mpg' extension are video files, typically MPEG video format. Therefore, option C (Video) is correct.

LAN (Local Area Network), WAN (Wide Area Network), and MAN (Metropolitan Area Network) are all types of computer networks categorized by their geographic coverage. Therefore, 'All of the above' is the correct answer.

WAN stands for Wide Area Network, which is a telecommunications network that extends over a large geographical area. This distinguishes it from other network types such as LAN (Local Area Network).

PIN stands for Personal Identification Number, not '470 PIN'. The term '470 PIN' is not a standard acronym or recognized term in networking or security contexts. Therefore, none of the provided options correctly define '470 PIN'.