Computer Network : Physical Layer (Test 1) : Free online Test by Teachexam

Question : What is a major reason for using multiplexing in communication systems?

To increase signal noise

To avoid sharing of bandwidth

To efficiently utilize a single transmission medium

To reduce the number of devices

Question : Which statement is true about Synchronous Time Division Multiplexing (TDM)?

Time slots are assigned only when data is available

Time slots are dynamically allocated

Each device gets a fixed time slot even if it has no data

It uses different frequencies for each device

Question : In Frequency Division Multiplexing (FDM), multiple signals are transmitted:

At the same time and same frequency

At different times and same frequency

At the same time but different frequencies

At different times and different frequencies

Question : Which of the following correctly differentiates Multiplexing and Demultiplexing?

Both combine signals

Multiplexing splits signals, Demultiplexing combines

Multiplexing combines signals, Demultiplexing separates them

Both operate only at sender side

Question : Multiplexing in computer networks follows which communication model?

One-to-one

One-to-many

Many-to-one

Many-to-many

Question : Which of the following correctly matches frequency range and medium?

Radio waves – 300 GHz to 400 THz

Microwaves – 1 GHz to 1000 GHz

Infrared – 3 kHz to 1 GHz

Radio waves – 1 GHz to 1000 GHz

Question : Why is infrared transmission considered more secure compared to other unguided media?

It has very low frequency

It cannot penetrate walls

It travels long distances

It uses satellites

Question : Which of the following is a key characteristic of microwave transmission?

Does not require antenna alignment

Travels in all directions equally

Requires line-of-sight communication

Cannot be affected by weather

Question : Which property makes radio waves suitable for broadcasting?

Line-of-sight transmission

High attenuation

Omnidirectional propagation

Limited range

Question : Which of the following correctly defines unguided transmission media?

Data transmission using optical fiber cables

Transmission using electromagnetic waves without physical medium

Transmission using twisted pair cables

Transmission through coaxial cable only

Question : Which of the following is a major disadvantage of coaxial cable?

Low bandwidth

High interference

Failure in one part can affect the entire network

Cannot be used for TV transmission

Question : Which guided transmission medium uses light signals instead of electrical signals?

Twisted Pair Cable

Coaxial Cable

Optical Fiber

UTP Cable

Question : Why are wires in a twisted pair cable twisted together?

To increase cable weight

To reduce electromagnetic interference

To increase signal delay

To reduce bandwidth

Question : Which of the following is NOT a type of guided transmission media?

Twisted Pair Cable

Coaxial Cable

Optical Fiber

Microwave

Question : Which of the following statements correctly defines guided transmission media?

Data is transmitted through air using electromagnetic waves

Signals are confined within a physical path like cables

It is used only for wireless communication

It does not require any physical medium

Question : Which statement is correct regarding wired vs wireless transmission media?

Wireless media is more secure than wired media

Wired media depends mainly on signal characteristics

Wireless media provides more flexibility and mobility

Wired media is always cheaper than wireless

none

Question : Which of the following correctly matches unguided transmission media with its property?

Radio waves – unidirectional communication

Microwaves – require line-of-sight alignment

Infrared – long-distance communication

Satellite – low coverage area

none

Question : Which factor refers to the weakening of a signal over distance in transmission media?

Noise

Distortion

Attenuation

Interference

none

Question : Which of the following is NOT a characteristic of guided (wired) transmission media?

Uses physical cables

Offers higher security

Signals travel through air or space

Less interference compared to wireless

none

Question : What is the primary function of transmission media in a computer network?

To store data permanently

To process data into information

To provide a path for data transmission between devices

To encrypt network data

none

Question : What is the main purpose of quantization in digital transmission?

To reduce noise

To assign discrete values to sampled signals

To increase bandwidth

To convert binary to analog

none

Question : Which of the following is NOT a step in Pulse Code Modulation (PCM)?

Quantization

Binary Encoding

Multiplexing

Sampling

none

Question : Which technique modifies PAM signals to produce a fully digital signal?

FDM

PCM

ASK

TDM

none

Question : Why is Pulse Amplitude Modulation (PAM) not directly suitable for digital communication?

It cannot sample signals

It produces analog pulses instead of digital signals

It increases noise significantly

It requires complex hardware

none

Question : Which of the following processes is responsible for converting a continuous analog signal into discrete digital values?

Modulation

Quantization

Sampling

Encoding

none