Page:Electronics Technician - Volume 7 - Antennas and Wave Propagation - NAVEDTRA 14092.pdf/118

 3-31. In practical applications, which of the following dimensions describes the wide dimension of the waveguide at the operating frequency?
 * 1) 0.1 wavelength
 * 2) 0.2 wavelength
 * 3) 0.5 wavelength
 * 4) 0.7 wavelength

3-32. Which of the following fields is/are present in waveguides?
 * 1) E field only
 * 2) H field only
 * 3) E and. H fields
 * 4) Stationary fields

3-33. A difference in potential across a dielectric causes which of the following fields to develop?
 * 1) Electric only
 * 2) Magnetic only
 * 3) Electromagnetic

3-34. H lines have which. of the following distinctive characteristics?
 * 1) They are continuous straight lines
 * 2) They are generated by voltage
 * 3) They form closed loops
 * 4) They form only in the waveguide

3-35. For an electric field to exist at the surface of a conductor, the field must have what angular relationship to the conductor? 3 45° 4 90°
 * 0°
 * 1) 30°

3-36. If the wall of a waveguide is perfectly flat, the angle of reflection is equal to which of the following angles?
 * 1) Cutoff
 * 2) Incidence
 * 3) Refraction
 * 4) Penetration

3-37. The cutoff frequency in a waveguide occurs at exactly what angle of reflection?
 * 10°
 * 30°
 * 45°
 * 90°

3-38. How does the group velocity of an electromagnetic field in a waveguide compare to the velocity of a wavefront through free space?
 * 1) Group velocity is somewhat faster
 * 2) Group velocity is somewhat slower
 * 3) Group velocity is twice that of free velocity
 * 4) Free velocity is twice that of group velocity

3-39. The group velocity of a wavefront in a waveguide may be increased by which of the following actions?
 * 1) Decreasing the frequency of the input energy
 * 2) Increasing the frequency of the input energy
 * 3) Increasing the power of the input energy
 * 4) Decreasing the power of the input energy

3-40. The various field configurations that can exist in a waveguide are referred to as
 * 1) wavefronts
 * 2) modes of operation
 * 3) fields of operation
 * 4) fields of distribution

3-41. The most efficient transfer of energy occurs in a waveguide in what mode? 14
 * 1) Sine
 * 2) Dominant
 * 3) Transverse
 * 4) Time-phase