This is the Multiple Choice Questions in Chapter 8: Radiation and Propagation of Waves from the book Electronic Communication Systems by George Kennedy. If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.
Start Practice Exam Test Questions
Choose the letter of the best answer in each questions.
1. Indicate which one of the following terms applies to troposcatter propagation:
- a. SIDs
- b. Fading
- c. Atmospheric storms
- d. Faraday rotation
2. VLF waves are used for some type of services because
- a. of the low powers required
- b. the transmitting antennas are of convenient size
- c. they are very reliable
- d. the penetrate the ionosphere easily
3. Indicate which of the following frequencies cannot be used for reliable beyond-the-horizon terrestrial communications without repeaters:
- a. 20 kHz
- b. 15 MHz
- c. 900 MHz
- d. 12 GHz
4. High-frequency waves are
- a. absorbed by the F2 layer
- b. reflected by the D layer
- c. capable of use for long-distance communications on the moon
- d. affected by the solar cycle
5. Distances near the skip distance should be used for the sky-wave propagation
- a. to avoid tilting
- b. to prevent sky-wave and upper ray interference
- c. to avoid the Faraday effect
- d. so as nor to exceed the critical frequency
6. A ship-to-ship communications system is plagued by fading. The best solution seems to be use of
- a. a more directional antenna
- b. a broadband antenna
- c. frequency diversity
- d. space diversity
7. A range of microwave frequencies more easily passed by the atmosphere than are the others is called a
- a. window
- b. critical frequency
- c. gyro frequency range
- d. resonance in the atmosphere
8. Frequencies in the UHF range normally propagate by means of
- a. ground waves
- b. sky waves
- c. surface waves
- d. space waves
9. Tropospheric scatter is used with frequencies in the following range:
- a. HF
- b. VHF
- c. UHF
- d. VLF
10. The ground wave eventually disappears, as one moves away from the transmitter, because of
- a. interference from the sky wave
- b. loss of line-of-sight conditions
- c. maximum single-hop distance limitation
- d. tilting
11. 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
12. As electromagnetic waves travel in free space, only one of the following can happen to them:
- a. absorption
- b. attenuation
- c. refraction
- d. reflection
13. The absorption of radio waves by the atmosphere depends on
- a. their frequency
- b. their distance from the transmitter
- c. the polarization of the waves
- d. the polarization of the atmosphere
14. Electromagnetic waves are refracted when they
- a. pass into a medium of different dielectric constant
- b. are polarized at right angles to the direction of propagation
- c. encounter a perfectly conducting plane
- d. pass through a small slot in a conducting plane
15. Diffraction of electromagnetic waves
- a. is caused by reflections from the ground
- b. arises only with spherical wavefronts
- c. will occur when the waves pass through a large slot
- d. may occur around the edge of a sharp obstacle
16. When microwave signals follow the curvature of the earth, this is known as
- a. the Faraday effect
- b. ducting
- c. tropospheric scatter
- d. ionospheric reflection
17. Helical antennas are often used for satellite tracking at VHF because of
- a. troposcatter
- b. superrefraction
- c. ionospheric refract
- d. the Faraday effect
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