9
2-11. What is the approximate wavelength, in
feet, of a radio wave with a frequency of
5,000 kHz?
1. 197 feet
2. 1,970 feet
3. 19,700 feet
4. 197,000 feet
2-12. The polarity of a radio wave is determined
by the orientation of (a) what moving field
with respect to (b) what reference?
1. (a) Electric
(b) earth
2. (a) Electric
(b) antenna
3. (a) Magnetic
(b) antenna
4. (a) Magneti
(b) earth
2-13. Energy radiated from an antenna is
considered horizontally polarized under
which of the following conditions?
1. If the wavefront is in the horizontal
plane
2. If the magnetic field is in the horizontal
plane
3. If the electric field is in the horizontal
plane
4. If the induction field is in the
horizontal plane
2-14. The ability of a reflecting surface to reflect
a specific radio wave depends on which of
the following factors?
1. Striking angle
2. Wavelength of the wave
3. Size of the reflecting area
4. All of the above
THIS SPACE LEFT BLANK
INTENTIONALLY.
Figure 2-A.—Reflected radio waves.
IN ANSWERING QUESTION 2-15, REFER TO
FIGURE 2-A.
2-15. If the two reflected radio waves shown in
the figure are received at the same instant
at the receiving site, what will be the
effect, if any, on signal quality?
1. A stronger signal will be produced
2. A weak or fading signal will be
produced
3. The signal will be completely canceled
out
4. None
2-16. The bending of a radio wave because of a
change in its velocity through a medium is
known as
1. refraction
2. reflection
3. deflection
4. diffraction
2-17. Radio communications can be diffracted
to exceptionally long distances through the
use of (a) what frequency band at (b) what
relative power level?
1. (a) Very low frequency
(b) Low power
2. (a) Very high frequency
(b) Low power
3. (a) Very low frequency
(b) High power
4. (a) Very high frequency
(b) High power
