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:
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. 300x106 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
- c. radiation
- 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. 300x106 m/s
- b. 300x106 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
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