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? 1. 0° 2. 30° 3. 45° 4. 90° 3-36. If  the  wall  of  a  waveguide  is perfectly   flat,   the   angle   of reflection   is   equal   to   which   of the 1. 2. 3. 4. following     angles? Cutoff Incidence Refraction Penetration 3-37. 3–38. 3-39. 3–40. 3-41. The   cutoff   frequency   in   a waveguide   occurs   at   exactly what   angle   of   reflection? 1. 10° 2. 30° 3. 45° 4. 90° 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 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 The   various   field   configura– tions  that  can  exist  in  a waveguide   are   referred   to   as 1. 2. 3. 4. The wavefronts modes   of   operation fields   of   operation fields    of    distribution most   efficient   transfer   of energy   occurs   in   a   waveguide   in what   mode? 1. Sine 2. Dominant 3. Transverse 4. Time–phase 14