Avionics MCQs –Types of Electronic Communication

1 - Question

Who discovered the radio waves?
a) Heinrich Hertz
b) Guglielmo Marconi
c) Thomas Edison
d) Alexander Bell
View Answer Answer: a
Explanation: The German physicist, Heinrich Hertz, first applied the theory given by Maxwell to prove the existence of radio waves in 1887. To honor him the unit of frequency is given his name.



2 - Question

What is the component that converts an electrical signal into a signal suitable for transmission in a given medium called?
a) Transmitter
b) Receiver
c) Amplifier
d) Duplexer
View Answer Answer: a
Explanation: A transmitter is an electronic component that converts the electric signals into a signal that is suitable for transmission in any given medium. It could be wires, air, water, land or even space.



3 - Question

What type of communication is used for underwater communication?
a) Radio communication
b) Microwave communication
c) SONAR
d) Satellite communication
View Answer Answer: c
Explanation: SONAR or SOund Navigation and Ranging is the transmission of information using sound waves. Since seawater is saline, it shorts out the electrical field in the radio waves and hence radio communication cannot be used. advertisement



4 - Question

Earth be considered as a communication medium.
a) True
b) False
View Answer Answer: a
Explanation: Earth can be considered as a communication medium as it can carry low frequency sound waves as well as conduct electricity. Communication for some submarines uses earth as a communication medium.



5 - Question

A device that can both transmit and receive is called as?
a) Transducer
b) Duplexer
c) Radar
d) Transceivers
View Answer Answer: b
Explanation: A transceiver is a device that contains the necessary electronic components for both transmission and receiving in the same medium. They have a common power supply and a common antenna for transmitting and receiving.



6 - Question

Radio transmission is always the speed of light irrespective of the medium.
a) True
b) False
View Answer Answer: b
Explanation: Radio waves travel at the speed of light only in free space. Other all communication medium attenuates the signal and lowers the speed of signal propagation.



7 - Question

What are the factors that affect signal propagation speed assuming no noise?
a) Wavelength of the signal
b) Frequency of the signal
c) Strength of electrical and magnetic fields
d) Permeability and permittivity of medium
View Answer Answer: d
Explanation: Since the EM waves are made of electric and magnetic fields, the resistance given by the medium to conduct electric and magnetic waves determine the speed of the EM wave. This is given by the permeability and the permittivity of the medium.



8 - Question

Which of the following is not an example of simplex communication?
a) Radio broadcast
b) TV broadcast
c) UAV/drone control from ground
d) Walkie talkie View Answer
View Answer Answer: d
Explanation: A simplex communication is when signal is sent from one end and is received at the other end. The communication in a walkie talkie is a two way communication.



9 - Question

What type of communication is used in a commercial walkie talkie?
a) Simplex
b) Full duplex
c) Half duplex
d) Multiplex
View Answer Answer: c
Explanation: Ia a walkie talkie the communication is two way but at a given time only one way communication is allowed. This type of communication is called as half duplex communication.



10 - Question

What type of communication is used between ATC and aircraft?
a) Simplex
b) Full duplex
c) Half duplex
d) Half simplex
View Answer Answer: c
Explanation: The communication between an aircraft and an ATC is half duplex meaning only one can speak at a time. The ATC asks or gives guidance for the aircraft, which the pilot has to fully hear before he can respond. If he responds before, the signal is not received by the ATC.



11 - Question

In what type of communication is time division multiplexing possible?
a) Analog
b) Digital
c) Duplex
d) Simplex
View Answer Answer: b
Explanation: In digital communication, the information can be quantized and transmitted. In time division multiplexing the information or digital data is quantized and transmitted in time slots which can be put together to get the original information.

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