MCQ ON Principles of Electronic
1. In a communications system, noise is most likely to affect the signal
a. at the transmitter
b. in the channel
c. in the information source
d. at the destination
View Answer:
Answer: Option B
Solution:
2. Indicate the false statement. Fourier analysis shows that a
sawtooth wave consist of
a. fundamental and subharmonic sine waves
b. a fundamental sine wave and an infinite number of harmonics
c. fundamental and harmonic sine waves whose amplitude decreases with
the harmonic number
d. sinusoidal voltages, some of which are small enough to ignore in practice
View Answer:
Answer: Option A
Solution:
3. Indicate the false statement. Modulation is used to
a. reduce the bandwidth used
b. separate differing transmissions
c. ensure that intelligence may be transmitted over long distances
d. allow the use of practicable antennas
View Answer:
Answer: Option A
Solution:
4. Indicate the false statement. From the transmitter the signal deterioration
because of noise is usually
a. unwanted energy
b. predictable in character
c. present in the transmitter
d. due to any cause
View Answer:
Answer: Option B
Solution:
5. Indicate the true statement. Most receivers conforms to the
a. amplitude-modulated group
b. frequency-modulated gr
c. superheterodyne group
d. tuned radio frequency receiver group
View Answer:
Answer: Option C
Solution:
6. Indicate the false statement. The need for modulation can best be
exemplified by the following.
a. Antenna lengths will be approximately λ/4 long
b. An antenna in the standard broadcast AM band is 16,000 ft
c. All sound is concentrated from 20 Hz to 20 kHz
d. A message is composed of unpredictable variations in both amplitude and
frequency
View Answer:
Answer: Option A
Solution:
7. Indicate the true statement. The process of sending and receiving started
as early as
a. the middle 1930s
b. 1850
c. the beginning of the twentieth century
d. the 1840s
View Answer:
Answer: Option D
Solution:
8. Which of the steps is not included in the process of reception?
a. decoding
b. encoding
c. storage
d. interpretation
View Answer:
Answer: Option B
9. The acoustic channel is used for which of the following?
a. UHF communications
b. single-sideband communication
c. television communications
d. person-to-person voice communications
View Answer:
Answer: Option D
Solution:
10. Amplitude modulation is the process of
a. superimposing a low frequency on a high frequency
b. superimposing a high frequency on a low frequency
c. carrier interruption
d. frequency shift and phase shift
View Answer:
Answer: Option A
1. 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. 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
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. 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.
4. Earth be considered as a communication medium.
a) True
b) False
View Answer
5. A device that can both transmit and receive is called as?
a) Transducer
b) Duplexer
c) Radar
d) Transceivers
View Answer
Answer: b
6. 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. 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. 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
Answer: d