 MCQs in Radiation and Wave Propagation Part I

(Last Updated On: September 10, 2019) This is the Multiples Choice Questions Part 1 of the Series in Radiation and Wave Propagation as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

Online Questions and Answers Topic Outline

• MCQs in Electromagnetic Radiation
• MCQs in Radio Spectrum
• MCQs in Wave Propagation
• MCQs in Radiation Patterns
• MCQs in Wavelength Calculations
• MCQs in Radiation Resistance
• MCQs in Diversity Systems

MCQs in Radiation and Wave Propagation Series

Following is the list of multiple choice questions in this brand new series:

Radiation and Wave Propagation MCQs
PART 1: MCQs from Number 1 – 50                        Answer key: PART I
PART 2: MCQs from Number 51 – 100                   Answer key: PART II
PART 3: MCQs from Number 101 – 150                 Answer key: PART III
PART 4: MCQs from Number 151 – 200                 Answer key: PART IV
PART 5: MCQs from Number 201 – 250                 Answer key: PART V
PART 6: MCQs from Number 251 – 300                 Answer key: PART VI
PART 7: MCQs from Number 301 – 350                 Answer key: PART VII
PART 8: MCQs from Number 351 – 400                 Answer key: PART VIII

Start Practice Exam Test Questions Part I of the Series

1. ________ is the amount of voltage induced in wave by an electro magnetic wave.

• a. receive voltage
• b. magnetic induction
• c. field strength
• d. power density

2. An electro magnetic wave consists of ___________.

• a. both electric and magnetic fields.
• b. an electric field only
• c. a magnetic field only
• d. non-magnetic field only

3. What is the lowest layer of the ionosphere?

• a. F1
• b. F2
• c. E
• d. D

4. Who propounded electro magnetic radiation theory?

• a. Sir Edward Appleton
• b. James Clerk Maxwell
• c. Christian Huygens
• d. Sir Isaac Newton

5. The D, E and F layers are known as ____________.

• a. Mark – space Layers
• b. Davinson- Miller Layers
• c. Kennely – Heaviside Layers
• d. Appleton Layers

6. Different grouping of the electromagnetic spectrum.

• a. band
• b. bandwidth
• c. channel
• d. group

7. What is the relation in degrees of the electric and magnetic fields in an electromagnetic wave?

• a. 180 degrees
• b. 90 degrees
• c. 270 degrees
• d. 45 degrees

8. A changing electric field gives rise to ________.

• a. a magnetic field
• b. sound field
• c. electromagnetic waves
• d. near and far fields

9. Frequencies in the UHF range propagate by means of

• a. ground waves
• b. sky waves
• c. surface waves
• d. space waves

10. In electromagnetic waves, polarization __________.

• a. is caused by reflection
• b. is due to the transverse nature of the waves
• c. results from the longitudinal nature of the waves
• d. is always vertical in an isotropic medium

11. Electromagnetic Waves are refracted when they ___________.

• a. pass into a medium of different dielectric constants
• b. are polarized at right angles to the direction of propagation
• c. encounter a perfectly conducting surface
• d. pass through a small slot in a conducting plane

12. What is the highest layer of the atmosphere?

• a. ionosphere
• b. stratosphere
• c. troposphere
• d. ozone layer

13. What is the thickest layer of the ionosphere?

• a. F2
• b. F1
• c. D
• d. E

14. Effective Earth radius to true earth radius ratio.

• a. index of refraction
• b. K factor
• c. Fresnel zone
• d. path profile

15. Fading due to interference between direct and reflected rays.

• a. atmospheric-multipath
• b. Fresnel zone
• c. reflection-multipath
• d. Rayleigh fading

16. The layer that reflects very low frequency waves and absorbs medium frequency waves.

• a. D Layer
• b. E Layer
• c. F1 Layer
• d. F2 Layer

17. What layer is used for high-frequency day time propagation?

• a. D Layer
• b. E Layer
• c. F1 Layer
• d. F2 Layer

18. What is the highest frequency that can be sent straight upward and be returned to earth?

• a. MUF
• b. skip frequency
• c. critical frequency
• d. gyro frequency

19. High frequency range is from?

• a. 0.3 to 3MHz
• b. 3 to 30MHz
• c. 30 to 300MHz
• d. 3to 30MHz

20. Medium frequency range is from

• a. 0.01 to 0.03 MHz
• b. 0.03 to 0.3MHz
• c. 0.3 to 3MHz
• d. 3 to 30 MHz

21. In tropospheric scatter propagation, the attenuation is dependent on

• a. scatter angle
• b. take-off angle
• c. antenna size
• d. the troposphere

22. If the transmitter power remains constant, an increase in the frequency of the sky wave will

• a. lengthen the skip distance
• b. increase the range of the ground wave
• c. reduce the length of the skip distance
• d. have no effect on the ground wave range

23. What is the unit of electric field strength?

• a. volts per square meter
• b. volt per square cm
• c. volts per meter
• d. millivolt per watt

24. Velocity of a radio wave in free space.

• a. 186,000 miles per sec
• b. 300×106 meters per sec
• c. 162,000 nautical mile per sec
• d. all of the above

25. Refers to the direction of the electric field vector in space.

• a. polarization
• b. directivity
• d. ERP

26. An TEM wave whose polarization rotates.

• a. vertically polarized
• b. omnidirectional
• c. horizontally polarized
• d. circularly polarized

27. velocity of light in free space

• a. 300×106 m/s
• b. 300×106 km/s
• c. 186,000 km/s
• d. 186,000 m/s

28. What is the effective radiated power of a repeater with 200W transmitter power output, 4dB feed line loss, 4dB duplexer and circulator loss, and 10dB feed line antenna gain?

• a. 2000 W
• b. 126 W
• c. 317 W
• d. 260 W

29. Radio wave that is far from its sources is called

• a. Plane wave
• b. isotropic wave
• c. vertical wave
• d. horizontal wave

30. Light goes from medium A to medium B at angle of incidence of 40 degrees. The angle of refraction is 30 degrees. The speed of light in B

• a. is the same as that in A
• b. is greater than that in A
• c. maybe any of these, depending on the specific medium
• d. is less than that in A

31. In a vacuum, the speed of an electromagnetic wave

• a. depends on its constant
• b. depends on its wavelength
• c. depends on its electric and magnetic fields
• d. is a universal constant

32. The depth of an object submerged in a transparent liquid

• a. always seems more that its actual depth
• b may seem less or more than its actual depth, depending on the object
• c. always seems less than its actual depth
• d. may seem less or more than its actual depth, depending on the transparent liquid

33. What is a wave front?

• a. a voltage pulse in a conductor
• b. a current in a conductor
• c. a fixed point in an electromagnetic wave
• d. a voltage pulse across a resistor

34. VHF ship station transmitters must have the capability of reducing carrier power to

• a. 1 W
• b. 10 W
• c. 25 W
• d. 50 W

35. Most of the effects an electro magnetic wave produces when it interacts with matter are due to its

• a. magnetic field
• b. speed
• c. frequency
• d. electric field

36. A mobile receiver experiences “dead” areas of reception as a result of

• a. atmospheric absorption
• b. tropospheric scatter
• c. sporadic E
• d. shading of the RF signal by hills and trees

37. When the electric field is perpendicular in the surface of the earth, what is the polarization of the TEM wave?

• a. elliptical
• b. vertical
• c. horizontal
• d. circular

38. When the magnetic field is perpendicular to the surface of the earth, what is the polarization of the TEM wave?

• a. circular
• b. horizontal
• c. vertical
• d. elliptical

39. When the magnetic field is parallel to the surface of the earth, what is the polarization of the TEM wave?

• a. elliptical
• b. horizontal
• c. vertical
• d. circular

40. What are the two interrelated fields considered to make up an electromagnetic wave

• a. an electric field and a current field
• b. an electric field and voltage field
• c. an electric field and a magnetic field
• d. a voltage and current fields

41. How does the bandwidth of the transmitted signal affect selective fading?

• a. it is more pronounced at narrow bandwidths
• b. it is equally pronounced at both narrow and wide bandwidths
• c. it is more pronounced at wide bandwidths
• d. the receiver bandwidth determines the selective fading

42. A wide-bandwidth communications systems in which the RF carrier varies according to some predetermined sequence.

• a. amplitude compandored single sideband
• b. SITOR
• c. spread spectrum communication
• d. time-domain frequency modulation

43. A changing magnetic field gives rise to

• a. sound field
• b. magnetic field
• c. electric field
• d. nothing in particular

44. When a space-wave signal passes over a mountain ridge, a small part of the signal is diffracted down the far side of the mountain. This phenomenon is called

• a. discontinuity scattering
• b. troposheric ducting
• c. knife-edge diffraction
• d. space-wave refraction

45. The index of refraction of a material medium

• a. is greater than 1
• b. is less than 1
• c. is equal to 1
• d. maybe any of the above

46. At what speed do electromagnetic waves travel in free space?

• a. approximately 468 million meters per second
• b. approximately 186300 ft/s
• c. approximately 300 million m/s
• d. approximately 300 million miles/s

47. What is the effective earth radius when surface refractivity, and N equals 300?

• a. 6370 km
• b.7270 km
• c.7950 km
• d. 8500 km

48. If N = 250, what is the earth radius K-factor?

• a. 1.23
• b. 1.29
• c. 1.33
• d. 1.32

49. Electric field that lies in a plane perpendicular to the earths surface

• a. vertical polarization
• b. horizontal polarization
• c. circular polarization
• d. elliptical polarization

50. Electric field that lies in a plane parallel to the earth’s surface

• a. vertical polarization
• b. horizontal polarization
• c. circular polarization
• d. elliptical polarization

Complete List of MCQs in Communications Engineering per topic

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