laboursonline – MCQs, Mock Tests | Computer Hardware and Networking NETWORKING /PHYSICAL LAYER SET 3

If the bit rate for a 16-QAM signal is 4000 bps, what is the baud rate?

1. 300
2. 400
3. 1000
4. 1200

✅ Correct Answer: 3

If the baud rate for a 64-QAM signal is 2000, what is the bit rate?

1. 300
2. 400
3. 1000
4. 12000

✅ Correct Answer: 4

Given an AM radio signal with a bandwidth of 10 KHz and the highest-frequency component at 705 KHz, what is the frequency of the carrier signal?

1. 700 KHz
2. 705 KHz
3. 710 KHz
4. Cannot be determined from given information

✅ Correct Answer: 1

______ conversion is the process of changing one of the characteristics of an analog signal based on the information in the digital data.

1. Digital-to-analog
2. Analog-to-analog
3. Analog-to-digital
4. Digital-to-digital

✅ Correct Answer: 1

Which of the following is not a digital-to-analog conversion?

1. ASK
2. PSK
3. FSK
4. AM

✅ Correct Answer: 4

In _________, the frequency of the carrier signal is varied to represent data. Both peak amplitude and phase remain constant.

1. ASK
2. PSK
3. FSK
4. QAM

✅ Correct Answer: 3

In ________, the phase of the carrier is varied to represent two or more different signal elements. Both peak amplitude and frequency remain constant.

1. ASK
2. PSK
3. FSK
4. QAM

✅ Correct Answer: 2

A constellation diagram shows us the __________ of a signal element, particularly when we are using two carriers (one in-phase and one quadrature).

1. amplitude and phase
2. amplitude and frequency
3. frequency and phase
4. None of the above

✅ Correct Answer: 1

Quadrature amplitude modulation (QAM) is a combination of ___________.

1. ASK and FSK
2. ASK and PSK
3. PSK and FSK
4. None of the above

✅ Correct Answer: 2

________ uses two carriers, one in-phase and the other quadrature.

1. ASK
2. PSK
3. FSK
4. QAM

✅ Correct Answer: 4

_____ conversion is the representation of analog information by an analog signal.

1. Digital-to-analog
2. Analog-to-analog
3. Analog-to-digital
4. Digital-to-digital

✅ Correct Answer: 2

Analog-to-analog conversion is needed if the available bandwidth is _______.

1. low-pass
2. band-pass
3. either (a) or (b)
4. neither (a) nor (b

✅ Correct Answer: 2

Which of the following is not an analog-to-analog conversion?

1. AM
2. PM
3. FM
4. QAM

✅ Correct Answer: 4

In _____ transmission, the carrier signal is modulated so that its amplitude varies with the changing amplitudes of the modulating signal.

1. AM
2. PM
3. FM
4. none of the above

✅ Correct Answer: 1

In _____ transmission, the frequency of the carrier signal is modulated to follow the changing voltage level (amplitude) of the modulating signal. The peak amplitude and phase of the carrier signal remain constant, but as the amplitude of the information signal changes, the frequency of the carrier changes correspondingly.

1. AM
2. PM
3. FM
4. None of the above

✅ Correct Answer: 3

In _____ transmission, the phase of the carrier signal is modulated to follow the changing voltage level (amplitude) of the modulating signal.

1. AM
2. PM
3. FM
4. None of the above

✅ Correct Answer: 2

In _______, the peak amplitude of one signal level is 0; the other is the same as the amplitude of the carrier frequenc

1. PSK
2. OOK
3. FSK
4. none of the above

✅ Correct Answer: 2

How many carrier frequencies are used in BASK?

1. 2
2. 1
3. 0
4. None of the above

✅ Correct Answer: 1

How many carrier frequencies are used in BFSK?

1. 2
2. 1
3. 0
4. None of the above

✅ Correct Answer: 2

How many carrier frequencies are used in QPSK?

1. 2
2. 1
3. 0
4. None of the above

✅ Correct Answer: 1

The constellation diagram of BASK has ______ dots.

1. 2
2. 1
3. 0
4. none of the above

✅ Correct Answer: 1

The constellation diagram of BPSK has ______ dots.

1. 2
2. 1
3. 0
4. None of the above

✅ Correct Answer: 1

The constellation diagram of QPSK has ______ dots.

1. 2
2. 1
3. 4
4. None of the above

✅ Correct Answer: 3

The constellation diagram of 16-QAM has ______ dots.

1. 4
2. 16
3. 8
4. None of the above

✅ Correct Answer: 2

The Federal Communications Commission (FCC) allows ______kHz for each AM station.

1. 5
2. 10
3. 20
4. None of the above

✅ Correct Answer: 2

The Federal Communications Commission (FCC) allows ______ kHz for each FM station.

1. 20
2. 100
3. 200
4. None of the above

✅ Correct Answer: 2

Which of the following layer decide the transmission rate in a Network?

1. Physical layer
2. Data link layer
3. Network layer
4. Transport layer

✅ Correct Answer: 1

What is the main function of DSLAM?

1. Convert analog signal into digital signal
2. Covert digital signal into analog
3. Used in router to detect the loss packets
4. None of the above

✅ Correct Answer: 1

What is the use of Bridge in Network?

1. to connect LANs
2. to separate LANs
3. to control Network Speed
4. All of the above

✅ Correct Answer: 1

Which of the following is not the possible ways of data exchange?

1. Simplex
2. Multiplex
3. Half-duplex
4. Full-duplex

✅ Correct Answer: 2

This kind of data transmission allows data to be transmitted in both directions on a signal carrier at the same time.

1. full-duplex
2. duplex
3. half-duplex
4. All of the above

✅ Correct Answer: 1

This kind of data transmission allows data to be transmitted in both directions on a signal carrier at the same time.

1. full-duplex
2. duplex
3. half-duplex
4. All of the above

✅ Correct Answer: 1

What is the difference between a switch and a hub?

1. Switches operate at physical layer while hubs operate at data link layer
2. Switches operate at data link layer while hubs operate at transport layer
3. Switches operate at data link layer while hubs operate at physical layer
4. Switches operate at transport layer while hubs operate at physical layer

✅ Correct Answer: 3

MAC address is also known as __________.

1. Hardware address
2. Physical address
3. IP address
4. both and b above

✅ Correct Answer: 4

Repeater operates in which layer of the OSI model

1. Physical Layer
2. Network Layer
3. Data link Layer
4. Transport Layer

✅ Correct Answer: 1

Repeater function in the ...................... layer.

1. Physical
2. Data link
3. Network
4. None of These

✅ Correct Answer: 1

A repeater takes a weakened or corrupted signal and ............... it.

1. Amplifies
2. Regenerates
3. Resample
4. Reroute

✅ Correct Answer: 2

What device separates a single network into two segments but lets the two segments appear as one to higher protocols?

1. Switch
2. Bridge
3. Router
4. Gateway

✅ Correct Answer: 2

Which of the following is used for modulation and demodulation?

1. modem
2. gateway
3. protocols
4. multiplexer

✅ Correct Answer: 1

Which of the following device is used to connect two systems, especially if the systems use different protocols?

1. hub
2. bridge
3. gateway
4. repeater

✅ Correct Answer: 3

The cheapest modems can transmit

1. 100 bits per second
2. 300 bits per second
3. 600 bits per second
4. 900 bits per second

✅ Correct Answer: 2

The cheapest modems can transmit

1. 100 bits per second
2. 300 bits per second
3. 600 bits per second
4. 900 bits per second

✅ Correct Answer: 2

Computers cannot communicate with each other directly over telephone lines because they use digital pulses whereas telephone lines use analog sound frequencies. What is the name of the device which permits digital to analog conversion at the start of a long distance transmission?

1. Modem
2. Interface
3. Attenuation
4. Teleprocessor

✅ Correct Answer: 1

Demodulation is a process of

1. performing data description
2. converting analog to digital signals
3. converting digital to analog signals
4. multiplexing various signals into one high speed line signals

✅ Correct Answer: 2

Demodulation is the process of

1. converting digital signals to analog signals
2. converting analog signals to digital signals
3. dividing the high-speed signals into frequency bands
4. combining many low speed channels into one high speed channel

✅ Correct Answer: 2

A devices that links two homogeneous packet-broadcast local networks, is

1. hub
2. bridge
3. repeater
4. gateway

✅ Correct Answer: 2

The physical layer, in reference to the OSI model, defines

1. the virtual circuit interface to packet-switched service
2. the interface between the X.25 network and packet mode device
3. data link procedures that provide for the exchange of data via frames that can be sent and received
4. All of the above

✅ Correct Answer: 2

Which of the following device copies electrical signals from one Ethernet to another?

1. hub
2. bridge
3. repeater
4. passive hub

✅ Correct Answer: 3

For connecting modem, a computer must be equipped with a port that conforms to the RS-232 standard of the Electronic Industries Association of America. What do the letters 'RS' stand for?

1. Registered source
2. Random sequence
3. Recognised standard
4. Recommended standard

✅ Correct Answer: 4

If communication software can be called the "traffic cop" of a micro communication system, then what should the modem be called?

1. Link
2. Park
3. Bridge
4. Interface

✅ Correct Answer: 3

If communication software can be called the "traffic cop" of a micro communication system, then what should the modem be called?

1. Link
2. Park
3. Bridge
4. Interface

✅ Correct Answer: 3

The fundamental requirements of private-to-public network interconnection methods which need to be provided in gateways is/are

1. adequate cost control mechanisms for administration of the private networks
2. universal accessibility for private network Data Terminal Equipment (DTE) c.
3. both (a) and (b)
4. to assign address to private network DTEs

✅ Correct Answer: 3

Interconnected networks need communication processors such as switches, routers, hubs, and gateways. Select the best fit for answer:

1. TCP/IP
2. Protocol
3. Open Systems
4. Internetwork processor

✅ Correct Answer: 4

What is the name of the device that converts computer output into a form that can be transmitted over a telephone line?

1. Modem
2. Teleport
3. Multiplexer
4. Concentrator

✅ Correct Answer: 1

Now-a-days computers all over the world can talk to each other. Which is one of the special accessories essential for this purpose?

1. Fax
2. Modem
3. Scanner
4. Keyboard

✅ Correct Answer: 2

Devices on one network can communicate with devices on another network via a

1. gateway
2. file server
3. utility server
4. printer server

✅ Correct Answer: 1

What is the name of the device that connects two computers by means of a telephone line?

1. cable
2. bus
3. Tape
4. modem

✅ Correct Answer: 4

The _____ layer is the layer closest to the transmission medium.

1. network
2. physical
3. transport
4. data link

✅ Correct Answer: 2

Which of the following allows devices on one network to communicate with devices on another network?

1. modern
2. gateway
3. t-switch
4. multiplexer

✅ Correct Answer: 2

RS-449/442-A/423-A is

1. the ratio of the number of data units in error to the total number of data units
2. a set of physical layer standards developed by EIA and intended to replace RS-232-C
3. a check bit appended to an array of binary digits to make the sum of the all the binary digits
4. a code in which each expression conforms to specific rules of construction, so that if certain errors occur in an expression the resulting expression will not conform to the rules of construction and

✅ Correct Answer: 2

A form of modulation In which the amplitude of a carrier wave is varied in accordance with some characteristic of the modulating signal, is known as

1. Aloha
2. modem
3. Angle modulation
4. Amplitude modulation

✅ Correct Answer: 4

A modulator converts a _____ signal to a(n) _____ signal.

1. digital; analog
2. analog; digital
3. PSK; FSK
4. FSK; PSK

✅ Correct Answer: 1

Repeaters are often used on an 802.3 network to help strengthen the signals being transmitted. As with the length of segments and the number of segments, a limit exists as to how many repeaters can be used between any two nodes. What is the maximum number of repeaters that can be used?

1. 1
2. 4
3. 9
4. 12

✅ Correct Answer: 2

A modem that is attached to the telephone system by jamming the phone's handset into two flexible receptacles in the coupler?

1. bridge
2. gateway
3. acoustic coupler
4. time-division multiplexer

✅ Correct Answer: 3

Which of the following statements is correct?

1. characteristic of LAN is unlimited expansion
2. characteristic of LAN is low cost access for low bandwidth channels
3. characteristic of the hub architecture of ARC-net is alternative routing
4. characteristic of the hub architecture of ARC-net is directionalized transmission

✅ Correct Answer: 4

A modem is connected in between a telephone line and a

1. network
2. computer
3. serial port
4. communication adapter

✅ Correct Answer: 4

A smart modem can dial, hang up and answer incoming calls automatically. Can you tell who provides the appropriate instruction to the modem for this purpose?

1. Telecommunications
2. Error detecting protocols
3. Communications software
4. Link access procedure (LAP)

✅ Correct Answer: 3

In a synchronous modem, the digital-to-analog converter transmits signal to the

1. terminal
2. equalizer
3. modulator
4. demodulator

✅ Correct Answer: 2

Which of the following connectivity devices is used to extend a network on a purely mechanical basis?

1. Active hub
2. Gateway
3. Router
4. Switch

✅ Correct Answer: 1

Who invented the modem?

1. AT & T Information Systems, USA
2. Digital Equipment Corpn.
3. Wang Laboratories Ltd.
4. Apple Computers Inc.

✅ Correct Answer: 1

Propagation time is equals to

1. Distance/Propagation speed
2. Propagation speed/Bandwidth
3. Message size/ Bandwidth
4. Bandwidth/Queuing time

✅ Correct Answer: 1

Period is the inverse of

1. Frequency
2. Phase
3. Amplitude
4. Signals

✅ Correct Answer: 4

The black and white TV is an example of

1. non periodic composite signal
2. periodic composite signal
3. periodic simple signal
4. None of the above

✅ Correct Answer: 1

The level of the signal is inversely proportional to the

1. Reliability of a system
2. Efficiency of a system
3. Accuracy of a system
4. Bandwidth of a system

✅ Correct Answer: 1

The Nyquist formula gives us any signal level while Shannon capacity gives us the

1. Lower Limit
2. Upper Limit
3. Specific signal level
4. Both (a) and (b)

✅ Correct Answer: 2