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Free download in PDF Electromagnetic Waves Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(1)
The distance in EDM is measured by______________
[A]
Phase difference
[B]
Amplitude
[C]
Frequency of the wave
[D]
Wave length
(2)
Tellurometer, a type of EDM uses which of the following waves?
[A]
Radio waves
[B]
Micro waves
[C]
Visible rays
[D]
Infra-red waves
(3)
Electromagnetic waves are represented in which of the following format?
[A]
Sinusoidal waves
[B]
Longitudinal waves
[C]
Transverse waves
[D]
None
(4)
What would be the value of length if the distance is given as 30m, m= 3 and the change in length is 8m.
[A]
7.34m
[B]
5.43m
[C]
7.43m
[D]
None of these
(5)
What is the wavelength of light waves if their frequency is 5.0X1014 Hz?
[A]
0.60 micro-m
[B]
0.60 m
[C]
6.0 mm
[D]
0.060 mm
(6)
What frequency are 20 mm microwaves?
[A]
15 GHz
[B]
73 GHz
[C]
100 MHz
[D]
None of these
(7)
What is the wavelength of a signal with a frequency of 150Mhz?
[A]
2m
[B]
20m
[C]
10m
[D]
None of these
(8)
What is the frequency of the EM wave with a wavelength of 12cm?
[A]
2.5Ghz
[B]
0.25Mhz
[C]
2.4Ghz
[D]
None of these
(9)
SHF Em waves are used in?
[A]
Satellite communication
[B]
Underwater communication
[C]
Ground to ground communication
[D]
Aircraft to ATC communication
Answer: Satellite communication
(10)
Which one of the following is not a reason for not using X-rays in communication?
[A]
High power is required
[B]
Stopped by ionizing effects
[C]
Highly attenuated
[D]
None of these
Answer: Stopped by ionizing effects
(11)
The portion of the electromagnetic spectrum occupied by a signal is called ________
[A]
Bandwidth
[B]
Signal spectrum
[C]
Signal strength
[D]
Frequency width
(12)
Infrared radiation was discovered in 1860 by:
[A]
William Herschel
[B]
Thomas Young
[C]
William Wallaston
[D]
None of above
(13)
Which of the following rays is emitted by a human body?
[A]
IR-rays
[B]
UV-rays
[C]
X-rays
[D]
Visible rays
(14)
A free electron is placed in the path of a plane electromagnetic wave. The electron will start moving:
[A]
along the direction of propagation of the wave
[B]
in a plane containing the magnetic field and the direction of propagation
[C]
along the electric field
[D]
along the magnetic field
Answer: along the electric field
(15)
Electromagnetic waves ware transverse in nature is evident by:
[A]
diffraction
[B]
interference
[C]
polarization
[D]
reflection
(16)
The rms value of the electric field of the light coming from the sun is 720 N/C. The average total energy density of the electromagnetic wave is:
[A]
6.37×10–9 J/m3
[B]
3.3×10–3 J/m3
[C]
4.58×10–6 J/m3
[D]
81.35×10–12 J/m3
(17)
All electromagnetic waves travel through a vacuum at
[A]
speeds that are inversely proportional to their frequency
[B]
speeds that are proportional to their frequency
[C]
the same speed
[D]
None of the above
(18)
The E and B fields in electromagnetic waves are oriented
[A]
perpendicular to the wave's direction of travel, and also to each other
[B]
perpendicular to the wave's direction of travel, and parallel to each other
[C]
parallel to the wave's direction of travel, as well as to each other
[D]
None
Answer: perpendicular to the wave's direction of travel, and also to each other
(19)
Which of the following correctly lists electromagnetic waves in order from longest to shortest wavelength?
[A]
television, infrared, visible light, X-rays
[B]
gamma rays, ultraviolet, infrared, microwaves
[C]
microwaves, ultraviolet, visible light, gamma rays
[D]
radio waves, infrared, gamma rays, ultraviolet
Answer: television, infrared, visible light, X-rays
(20)
Modern EDM uses which among the following waves?
[A]
Visible rays
[B]
Modulated infra-red
[C]
Radio waves
[D]
None of these
Answer: Modulated infra-red
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