Quiz On Unit 2 Computer Network Class 11

Explanation
Optical fiber has the highest transmission speed in a network compared to coaxial cable, twisted pair cable, and electrical cable. This is because optical fiber uses light signals to transmit data, which allows for extremely fast transmission speeds. Light signals can travel at very high speeds, allowing for greater bandwidth and faster data transfer rates. In contrast, coaxial cable, twisted pair cable, and electrical cable use electrical signals, which have slower transmission speeds. Therefore, optical fiber is the correct answer for the transmission media with the highest transmission speed in a network.

Explanation
Half-duplex is the method of communication in which the transaction takes place in both directions, but only in one direction at a time. In other words, the communication can either be in the send mode or receive mode, but not both simultaneously. This means that the sender and receiver cannot transmit and receive data at the same time.

Explanation
A modem is a device that converts digital signals from a computer into analog signals that can be transmitted over telephone lines. This allows for the transmission of data over traditional telephone networks. Therefore, the statement that modems modulate digital signals into analog signals is true.

Explanation
The process of converting analog signals into digital signals so they can be processed by a receiving computer is referred to as digitising. This involves sampling the analog signal at regular intervals and quantizing the amplitude of each sample to a finite number of digital values. By converting the analog signal into a digital representation, it becomes easier to store, transmit, and manipulate the data using digital systems. Modulation refers to the process of encoding information onto a carrier signal, demodulation is the reverse process of extracting the original information from the modulated signal, and synchronizing involves coordinating different processes or devices to work together in a synchronized manner.

Explanation
A modem is not a transmission medium. A transmission medium refers to the physical path through which data is transmitted from one device to another. Telephone lines, coaxial cables, and microwave systems are all examples of transmission mediums because they provide a means for data to be transmitted. However, a modem is a device that modulates and demodulates signals to enable communication between a computer and an internet service provider. It is not a physical medium itself, but rather a device that facilitates communication over a transmission medium.

Explanation
Parallel transmission is a method of data transmission where multiple bits are sent simultaneously across multiple wires. This allows for faster data transfer compared to serial transmission, where bits are sent one after the other on a single wire. In parallel transmission, each bit has its own dedicated wire, which means that multiple bits can be transmitted at the same time. Therefore, the given statement that in parallel transmission, bits are transmitted simultaneously, each across its own wire, is true.

Explanation
In both asynchronous and synchronous serial transmission, bits are sent one at a time over a single wire. This means that each bit is transmitted individually, rather than in groups or in parallel. Asynchronous transmission does not require a clock signal and each bit is accompanied by start and stop bits to indicate the beginning and end of a transmission. Synchronous transmission, on the other hand, relies on a clock signal to synchronize the sender and receiver, but still transmits bits one at a time. Therefore, the statement is true.

Explanation
BNC connectors are commonly used in coaxial cable connections. Coaxial cables are widely used for transmitting audio, video, and data signals, making them suitable for various applications such as television, networking, and telecommunications. BNC connectors provide a secure and reliable connection between the coaxial cable and the device, ensuring efficient signal transmission. While BNC connectors can also be used in other types of cables, such as fiber optic and twisted pair cables, their primary and most common application is in coaxial cables.

Explanation
RJ-45 male and female connectors are not used in optical fiber networks. Optical fiber networks use different types of connectors, such as SC, LC, or ST connectors. RJ-45 connectors are commonly used in twisted pair cable networks, where they are used to connect devices such as computers, routers, and switches. Therefore, the correct answer is "none of the above" as RJ-45 connectors are not used in optical fiber networks.

Explanation
The correct answer is physical. The transmission media, such as cables or wireless signals, are the physical means through which data is transmitted. They are responsible for carrying the data from one point to another, and they operate at the lowest layer of the networking model. The physical layer is responsible for the physical transmission of bits over the transmission media.

Explanation
A BNC terminator is used to prevent the reflection of the signal. When a signal travels along a transmission line, it can encounter impedance mismatches at the end of the line. This can cause the signal to reflect back towards the source, resulting in signal degradation and interference. By terminating the line with a BNC terminator, the impedance is matched and the signal is absorbed, preventing reflections. This helps to maintain the integrity and quality of the signal being transmitted.

Explanation
The statement is incorrect. STP (Shielded Twisted Pair) cable is not specifically used by Unix systems. STP cables are used in networking to reduce electromagnetic interference and are commonly used in both Unix and non-Unix systems. Therefore, the correct answer is False.

Explanation
The statement is false because step index and graded index are not types of propagation mode for twisted pair cable. Rather, they are types of optical fiber cables. Twisted pair cables use different modes of propagation, such as differential mode and common mode, to transmit signals.

Explanation
UTP stands for Unshielded Twisted Pair. This refers to a type of cable commonly used for Ethernet connections. It consists of multiple pairs of twisted wires that are not shielded or protected by any additional covering. The twisting of the wires helps to reduce interference and crosstalk between the pairs, allowing for more reliable data transmission. UTP cables are widely used in networking and telecommunications applications.

Explanation
Fiber optics data transmission has several advantages. Firstly, it provides resistance to data theft as it is difficult to tap into the transmission without physically accessing the fiber. Secondly, it offers a fast data transmission rate as it can transmit data at high speeds over long distances. Lastly, fiber optics has a low noise level, meaning that the signal is less prone to interference and distortion. Therefore, all of the given options are advantages of using fiber optics data transmission.